ORGANIC CHEMISTRY
FOR THE
LABORATORY
BY
W. A. NOYES, Ph.D.,
ti
Professor of Chemistry in University of Illinois, Urbana, 111.
Second Edition, Revised and Enlarged
EASTON, PA.
THE CHEMICAL PUBLISHING,, CO.
1911
LONDON, ENGLAND:
WILLIAMS & NORGATE
14 HENRIETTA STREET, COVENT GARDEN, W. C.
COPYRIGHT, 1897, BY EDWARD HART.
COPYRIGHT, 1911, BY EDWARD HART.
PREFACE TO SECOND EDITION
In preparing a second edition of this book, Chapters on the
Analysis of Organic Compounds, on General Operations,, on
Ethers, on Hydroxy and Ketonic Acids and on Carbohydrates
have been added, and thirty new preparations, have, been included .
The Chapters in the book have also been rearranged . to corre-
spond more nearly with the order used. in the author's text-book.
It is hoped that this rearrangement ...will .not .interfere with the
use of the book by those who prefer some other text-book as
the basis for their instruction.. .
The tables for nitrogen have been recalculated on ^he= basis
of modern values for the weight of one liter and .for the. co-
efficient of expansion of nitrogen. Some similar tables in com-
mon use are about 0.4 per, cent, in error becau.se, old, erroneous
values for these constants . were .used in their;,, preparation-
It is more true than before that the number of preparations
given is too great, for the average studerit, to complete^ To meet, .
this difficulty classes may be divided into groups of four to six
students and each group be required tq complete nearly all .of ,
the preparations in the book, the preparations assigned to in- .
dividuals being different. Each individual- oij the group should
be expected to become familiar with all oft the, fundamental prin-
ciples of the preparations made by the members of his group. . ,
By this method the knowledge acquired, in a given time may tje .
considerably increased. .
I wish -to express my obligation to Professor R. S. Cur,tiss,. ..,.,.
Dr. C. G. Derick and Dr. L,. H. Cone who, have .made many,,
valuable suggestions Ayith regard to the revision; also rto Pro-
fessor Edward Hart, wjio furnished , the directions for -the, dis-
tillation of wood and separation of the* products formed, ?.s
these processes, are carried out in his laboratory. , at Lafayette
College.
304282
PREFACE TO FIRST EDITION
The science of organic chemistry rests, for its experimental
foundation, on the preparation, usually by synthetical means,
of pure compounds. Without a knowledge, based on personal
experience in the laboratory, of the relations involved and the
methods which may be used in such preparations, no satisfactory
knowledge of the science can be acquired. It has been the pur-
pose of the author in ' writing this book to classify the most
important of the laboratory processes which have been used in
the development of the science and to illustrate them by con-
crete examples.
Two distinct purposes have been kept in view. The first has
been to furnish the beginner with sufficiently full and accurate
directions and clear, concise, theoretical explanations of pro-
cesses which have been found successful in practical laboratory
experience. The second object has been to furnish the more
advanced student and practical worker with a guide which will
aid him in the selection of processes which are likely to be suc-
cessful for the preparation of compounds which he may desire
to use.
It is for this second reason, partly, that the number of pre-
parations given is considerably greater than it would be profitable
for the average student to prepare, and that the references to
the literature have been made quite full.
The student who uses the book is very earnestly advised to
begin each preparation with a careful study of the directions
given, and also of the literature of the subject. For the time
being, he should make himself thoroughly familiar with all of the
important relations of the substance with which he is working,
and with other methods of preparation which might be used.
Comparatively few preparations carefully studied in this way will
be of greater value than a much larger number mechanically
executed by simply following the directions of the book. The
PREFACE V
successful student must be able to use intelligently the larger
handbooks, especially that of Beilstein, and the original sources
in chemical journals. It need scarcely be remarked that a satis-
factory working knowledge of organic chemistry cannot be ac-
quired without the ability to use German books.
In some cases it may be well to undertake the preparation of
analogous substances in place of the ones which are given.
The majority of the processes described should be viewed from
the standpoint that they are applicable to many other similar
cases, though slight modifications are often necessary and as to
that the student should satisfy himself by examination of the
literature before he goes on with his work. In research work
chemists very often help themselves by a careful study of the
properties of bodies related, or analogous, to those which they
wish to prepare, and the habit of making comparisons of this
kind is very valuable.
It is not the intention of the author that the order of the
book should be necessarily, or, indeed, usually followed by the
student. He has a very firm conviction that laboratory work
of the sort provided for in this book should always accompany
the lecture-room or text-book work in organic chemistry, and
that the frequent lack of interest in the subject is often due to the
fact that the laboratory work is given a year or two after the
lectures, or that it is omitted altogether. If the book is used
in conjunction with the usual course of lectures to beginners, as
it is hoped that it may be, topics will naturally be selected in the
same general order as that followed in the lectures or text-book.
The discussion of special topics, such as crystallization, fil-
tration, distillation, distillation under diminished pressure, ex-
traction, etc. has been given in connection with preparations when
their use is required. Frequent references to these discussions
are given elsewhere, and they may also be readily found by means
of the index.
The author wishes to acknowledge his indebtedness to the
somewhat similar works of Levy, Gattermann, Erdmann, and E.
Fischer for many suggestions; also to a little book by Drs. A.
vi PREFACE
- A. No^es 'an'd S. P/Muttiken 'o r n the '"ClaTS Reactions of rganic
e Substances/' for some sagge'stion's" in 'writing* the chapter on the
L qualitative ' exaniination of 'organic substances. He" also 'desires
' to" express his thanks to Mr. W. Er Bark 1 , whb* prepared the
drawings for the v bbok, a'nd" td^Mr. J. JyKe'sslfer, Jr., who has
' tested many of the directions' for preparations^ in 'the' laboratory.
I wish also to' express my smtere thanks to Dr. J. Bishop IHngle,
"Who 1 has' read : carefully all of the proofs, and has made many
valuable suggestions. *
TABLE OF CONTENTS
, Chapter I PAGE
ANALYSIS OF COMPOUNDS OF CARBONS . i
Chapter II
GENERAL OPERATIONS : 25
1. Carbon tetrachloride and aniline.,. 25
2. Urea, phthalic anhydride, />-toluidine 29
3. Specific gravity of alcohol 32
4. Distillation of wood 54
Chapter III
HYDROCAREONS 38
5. Methane 41
6. Ethane 42
7. Ethylene dibromide 44
8. Acetylene 47
9. Acetylene 49
10. Benzene 50
11. Cyclohexane 50
12. Paraxylene 54
13. Cymene 56
14. Diphenyl 56
1 5. Diphenyl methane 57
16. Triphenyl methane 58
17. Triphenylmethyl and triphenylmethyl peroxide 60
18. Anthracene 60
19. Zinc ethyl - 61
Chapter IV
ALCOHOLS AND PHENOLS 64
20. Absolute ethyl alcohol 67
21. Allyl alcohol . t : . . . 69
4 22. Paracresol 70
23. Benzyl alcohol 72
24. Phenyl methyl. , carbinol ,......-. ..... .73
25. Triphenyl . carbinol . , 74
26. Ethylene glycol 75
27. Hydroquinone . . . 76
28. Alizarin 78
Vlll CONTENTS
Chapter V PAGE
ETHERS 81
29. Ethyl ether . 81
30. Anisole, Phenyl Methyl ether 83
31. Phenyl ether of salicyclic acid . . 84
Chapter VI
ALDEHYDES, KETONES AND THEIR DERIVATIVES 86
32. Acetaldehyde 89
33. Acetone, (Propanone) 92
34. Acetoxime 93
35. Semicarbazone of acetone ' 94
36. Benzaldehyde 96
37. Benzoin 97
38. Benzil 98
39. Cinnamic acid 99
40 Phenyl hydrazone of acetophenone 100
41. Benzophenone 101
42. Anthraquinone 103
43. Orthobenzoylbenzoic acid 103
44. Xanthone 105
Chapter VII
ACIDS 106
45. Formic acid 115
46. Isovaleric acid 1 16
47. Propionic and butyric acids 119
48. Stearic Acid 121
49. Camphoric acid ' 122
50. Benzoic acid 125
51. o- and />-Nitrobenzoic acids 126
_ _ 52. Paratoluic acid 131
53. Cinnamic acid 133
54. Hydrocinnamic acid 134
55. Malonic ester 136
56. Succinic acid 139
57. Phenolphthalein 141
Chapter VIII
DERIVATIVES OF ACIDS 144
58. Acetyl chloride 148
59. Acetic anhydride 149
60. Succinic anhydride ' 150
61. Ethyl acetic ester 151
CONTENTS ix
\
PAGE
62. Saponification of an ester 152
63. Ethyl succinic ester 152
64. Benzoic ethyl ester 153
65. Phenyl benzoate 154
66. Di-acetyl tartaric ethyl ester 154
67. Acetamide 156
68. Acetanilide 157
69. Urea 158
70. Phenyl sulphonamide 159
71. Phenyl cyanide 161
72. Uric acid 162
Chapter IX
HYDROXY AND KETONIC ACIDS 164
73. Salicylic acid 165
74. Mendelic acid 166
75. Acetoacetic ester 170
76. Diacetyl succinic ester 175
77. Hydrocinnamic acid 176
78. Antipyrine 178
79. Succinylosuccinic ester t 180
80. Ethyl ester of mesoxalic acid 182
Chapter X
CARBOHYDRATES . 184
81. Fehling's solution. Inversion of sucrose 185
82. Maltose and dextrin 187
83. Specific rotation of sucrose and invert sugar 188
84. Schweitzer's reagent. Solution of cellulose 189
85. Preparation of furfural from a pentose 190
86. Glucosazone 191
87. Levulinic acid 192
Chapter XI
HALOGEN COMPOUNDS 194
88. Methyl iodide 196
89. Ethyl bromide 197
90. Para-dibrombenzene 198
91. Benzyl chloride 199
92. Parabromtoluene 201
93. a-Brom-butyric acid 203
94. Ethyl ester of monobromomalonic acid 205
95. Chloroform 206
96. lodoform 207
X CONTENTS
Chapter XII
PAGE
NITRO COMPOUNDS 209
- -97. Nitrobenzene ...:...' 210
98. m-Dinitrobenzene 211
99. a-Nltronaphthalene . . . 212
100. w-Nitro-Amino-0-Nitrotoluene . . . . . 214
102. Meta-nitro-benzoic acid 215
Chapter XIII
AMINES 217
103. Aniline ...'........ 220
104. />-Amino-0-nitrotoluene 221
105. />-Phenylenediamine . . 223
106. Diethylamine 224
107. Isopropylamine 226
108. w-Phenyl-ethyl-amine -227
109. Aminomethylphen 229
1 10. Glycocoll ' 231
in. Hippuric acid 232
1 12. a-Aminoisobutyric acid 233
113. Anthranilic acid v. 234
114. Indigo from anthranilic acid 235
115. Aminomalonic ester .......' 237
1 16. Skraup's synthesis of quinoline 238
117. 2,7-Dimethyl-4-ketodihydroquinazoline or 2,7-Dimethyl-4-hy-
droxyquinazoline 239
1 18. Collidinedicarboxyllic ester .'.....'.;..;-..'. '. . 240
119. Malachite green 241
Chapter XIV
DIAZO, HYDRAZO, NITROSO AND OTHER NITROGEN COMPOUNDS 244
120. Hydrazobenzene 248
121. Azobenzene ..........: : . 249
122. Benzene diazonium chloride 249
123. />-Aminoazobenzene .....:....'. 250
124. />-Sulphobenzene-azo-a-riaphthylamine ......:..:..:.:...:... 252
125. Helianthine .......*.. ....:... 253
126. Phenyl hydrazine J . 254
127. jS-Phenylhydroxylamine 255
CONTENTS XI
Chapter XV PAGE
SULPHUR COMPOUNDS 257
128. Sulphanilic acid ., 258
129. 0-and-/>-Toluene sulphonamides 259
130. Trimethylsulphonium iodide 261
131. Thiophene 262
Chapter XVI
QUALITATIVE EXAMINATION OF CARBON COMPOUNDS 264
REAGENTS , 272
Chapter I
ANALYSIS OF COMPOUNDS OF CARBONS
Literature. H. Meyer: Analyse und Konstitutionsermittelung organi-
scher Verbindungen, 2 Auflage, pp. 146-320; Benedict: Amer. Chem. J.,
2 3i 323 and 324; J. Am. Chem. Soc., ai, 389; Mabery and Clymer: Ibid,
22, 213; Dennstedt: Anleitung zur vereinfachten Elementaranalyse, 2
Auflage, 1906, also Ber., 4i> 600; Z. anal chem., 42, 41?-
Determination of Carbon and Hydrogen. The apparatus re-
quired for the determination of carbon and hydrogen in a com-
pound containing only these elements or these elements with
oxygen or nitrogen, or both, is as follows:
1. A combustion tube 10 to 12 cm. longer than the combustion
furnace. The ends should be cut square across and rounded,
without narrowing, in the blast flame, heating at first a little
distance from the end. The tube should be 12 to 15 mm. in
internal diameter, of infusible glass and with walls about 2 mm.
thick.
2. Copper oxide, granulated or wire form.
3. A copper spiral 10 to 12 cm. long, two spirals 2 to 3 cm.
long, and one 5 to 6 cm. The two short spirals should fit the
tubes closely, the other two loosely. Each spiral is made by
wrapping pure copper wire gauze around a stiff copper wire,
which should be bent to a loop or hook at one end. The long
copper spiral is required only for compounds containing nitrogen
and should be oxidized superficially by holding it in the flame of
a Bunsen burner and then reduced by plunging it while hot into
a test-tube containing about one-half cc. of pure methyl alcohol.
The tube should be stoppered till the spiral has cooled and the
latter dried at 150 and placed, while hot, in a desiccator.
4. A 105 mm. U-tube filled with calcium chloride. The cal-
cium chloride should be in granular form and its solution in water
must not react alkaline. The form of tube shown in Fig. I is
most suitable. The bulb A is so constructed that the water col-
ORGANIC CHEMISTRY
lecting in the bulb cannot run into the portion of the tube con-
taining the calcium chloride. The rubber stopper at B must
fit tightly and should be cut even with the top of the tube and
Pig. i.
covered with sealing wax. It should completely fill that por-
tion of the tube above the side arm C so that the current of gas
through the tube will be direct. A small plug of cotton should
be placed below the stopper to prevent dust from the calcium
chloride being carried out mechanically. Short caps of rub-
ber tubing fitting the ends of the U-tube closely and closed
with glass rods should be provided to protect the tube from the
air when not in use and similar caps, also, for the potash
bulbs. The caps must not contain loose sulphur. When great
accuracy is desired, concentrated sulphuric acid is a more per-
fect drying agent than calcium chloride. See Benedict, Am.
Chem. J., 23, 326.
5. Potash bulbs, best of the improved Geissler form, having
diaphragms within each bulb, also having a small tube to be filled
ANALYSIS OF COMPOUNDS OF CARBONS 3
with granular stick potash "ground on." Instead of potash
B
Fig. 2.
bulbs many chemists prefer a U-tube filled with soda-iime.
(Benedict: Am. Chem. J., 23, 323 and 334.) The portion of
the U-tube on the side where the gases leave the tube should be
filled with calcium chloride for 3 to 4 cm., or a second tube con-
taining glass wool and a little sulphuric acid may be used and
weighed with the soda-lime tube.
If potash bulbs are used, they are filled with a solution of
potassium hydroxide of about 1.27 sp. gr. prepared by dissolv-
ing 35 grams of potassium hydroxide in 100 cc. of water. Only
enough of the solution should be used so that the three lower
bulbs are filled and a very little passes into the fourth bulb
when air is passed through the system. After filling, the tube
B, through which the solution is drawn, it should be carefully
cleaned both within and without before putting on the rubber
caps. It is safer to use the bulbs only twice before refilling and
in no case should they be used after acid potassium carbonate
'separates in the first bulb.
ORGANIC CHEMISTRY
6. A small calcium chloride tube and a piece of rubber tub-
ing to connect it with the potash tube of the potash bulbs.
7. Short pieces of rubber tubing fitting the tubes of the
potash bulbs and of the U-tube tightly. The tubing should have
walls about 2 mm. thick. If white tubing is used, the tubes
should be soaked in a solution of sodium hydroxide to remove
sulphur and thoroughly washed and dried. Red or black tubing
is usually preferred, The tubing
should be stretched and carefully
examined for minute pores or holes.
8. Two gasometers or large bottles
filled respectively with air and oxygen.
A galvanized iron or zinc gasometer
should not be used because of the
danger of contaminating the gases
with hydrogen.
9. Two sets of purifying apparatus
to remove carbon dioxide and mois-
ture from the air and oxygen. A
suitable form is shown in Fig. 3.
The space around the inner tube is
filled with soda-lime and the inner
tube, which passes loosely through a
larger tube that separates it from the
soda-lime, is filled with pumice dren-
ched with concentrated sulphuric acid
(Benedict, Am. Chem, J., 23, 332).
If calcium chloride is used to absorb
the water from the combustion, it
should be used last in the purifying
train, while if sulphuric acid is used
for the former, it should be used last in the the purifying train,
also. Calcium chloride leaves i.o mg. of water in one liter of a
gas dried by it at 15, 1.5 mg. at 20, 2.5 mg. at 25, and 3.3 mg.
at 30, while concentrated sulphuric acid leaves only about 0.002
mg. per liter at 15 to 19.
Fig- 3-
ANALYSIS OF COMPOUNDS OF CARBONS 5
The connections from the gasometer to the combustion tube
should be of glass, as far as possible with only short connections
of rubber tubing, the glass tubes being brought together within
the rubber. Moisture and other gases diffuse through India
rubber, and there is some danger of organic matter being vol-
atilized from the interior of a long rubber tube.
Between the purifying apparatus and the combustion tube a
three-way stop-cock is introduced so that either air or oxygen
may be passed through the tube at will and so that the rate of
either current may be accurately regulated.
10. A porcelain or platinum boat, or, for volatile substances,
a small bulb to contain the substance to be burned. Liquids which
boil above 250 at atmospheric pressure may be weighed in a
boat, but should be weighed immediately before burning. If
a bulb is used, it should have a not too narrow capillary stem, at
least 10 cm. long and should contain a small piece of copper oxide
to burn the portion of the vapor of the substances remaining in
the bulb. The bulb is filled by mearis of a small tube drawn
out to a fine capillary, which can be inserted through the capillary
of the bulb. Or it may be filled by heating the bulb and dipping
the capillary stem in the liquid, allowing the latter to be drawn
up as the bulb cools. The bulb should, of course, have a
capacity of only 0.3 to 0.5 cc. It should be placed in the com-
bustion tube in such a manner that by heating the portion of
the tube where the bulb rests, the liquid can be forced out into
some of the copper oxide which is still cold. Without this pre-
caution it is difficult to avoid too rapid combustion.
11. Rubber stoppers fitting the combustion tube, soft and of
the best quality. It is well to soak them in a solution of sodium
hydroxide for a short time to remove sulphur. They should,
of course, be washed clean and be dry.
12. Two asbestos shields to place over the combustion tube
at the ends of the furnace to protect the rubber stoppers.
ORGANIC CHEMISTRY
The
combustion tube is filled as shown in Fig. 4. If the
copper oxide is to be used for the first time, the
tube (without the reduced copper spiral) should
be placed in the furnace and heated to bright
redness in a slow current of air for an hour.
If the copper oxide and tube have been used
before, heating for half an hour will suffice.
The portion of the tube where the substance is
to be placed is then allowed to cool, while the
entrance of moist air is prevented by connecting
the exit end of the tube with a calcium chloride
or soda-lime tube.
The potash bulbs and U-tube are carefully
wiped with a clean dry cloth, and should be
allowed to stand in or near the balance (with the
caps on) for an hour before weighing. 1 They
are weighed zvithout the caps. The accuracy
+ of the weighing may be increased by using a
* counterpoise of exactly the same character and
kept beside the U-tube and potash bulbs during
all of the operations. If proper care is taken
and good common sense is used with regard to
the conditions of weighing and methods of hand-
s ling a reasonable degree of accuracy can be
^ secured without this precaution.
When the combustion tube has cooled suffi-
ciently, the reduced copper spiral is placed in
the front part of the tube (if the substance to
be analyzed contains nitrogen) and the rubber
stopper carrying the calcium chloride U-tube is
5 inserted and the potash bulbs connected to the
^ U-tube and the calcium chloride or soda-lime
tube connected to the exit of the potash bulbs
to protect them from moisture and carbon dioxide
1 A little radium in the balance case will dissipate electric
charges which are sometimes troublesome (T. W. Richards).
ANALYSIS OF COMPOUNDS OF CARBONS 7
from the air. In forcing the tube of the U-tube through the stopper
and in making the connections the tube and bulbs should always be
grasped by the small tube which is to be forced into the stopper
or connection, as the apparatus is fragile. The glass tubes should
be brought together within the connections and should be secured
against leakage by tying with fine copper wire, thread or by a
rubber thread made by breaking a rubber band. One of the
greatest dangers of the whole process is that of slight leaks
in the connections. After all of the connections are com-
plete, a test for leaks may be made by admitting oxygen from
the rear and after stopping the current, watching to see if the
solution in the potash bulbs falls back from the level to which it
Fig- 5-
is forced. The test is not always satisfactory, especially when a
part of the tube is warm.
When the absorption train has been properly connected to
the front end of the tube the stopper at the rear is removed,
the oxidized copper spiral taken out and put into a dry test tube,
which is immediately stoppered, the boat or bulb containing
0.15 to 0.25 grams of the substance introduced and the oxidized
spiral replaced with the least possible exposure to the air, since
copper oxide is hygroscopic. The rear stopper connecting with
the purifying trains for oxygen and air is then inserted and the
test for leaks referred to above, is made.
If no leak is found, light the first six or seven burners and
turn them very low, either individually, or by means of the
stop-cock regulating the gas supply for the whole furnace.
8 ORGANIC CHEMISTRY
Turn these burners up a little once in two minutes, by trie watch,
till the front portion of the tube shows faint redness, then pro-
ceed slowly with the burners further back toward the substance.
At the same time light one burner under the spiral in the rear of
the boat or bulb, and start a very slow current of oxygen
through the tube. The portion of the tube in the neighborhood
of the boat must be heated very gradually in all. cases so that
the substance is slowly volatilized and burned.
In the Berlin laboratory a clock-work device has been arranged
to move some -burners very slowly under the substance and se-
cure slow and uniform burning. A porcelain boat with twelve
compartments is used to hold the substance.
Substances vary greatly in the care which must be exercised
in burning them. The bubbles should never pass the potash bulbs
more rapidly than they can be counted. Explosive substances and
sometimes other substances may be mixed in the boat with line
copper oxide to advantage. The copper oxide to be used for
this purpose should be ignited in a porcelain or copper crucible
and cooled in a desiccator. Salts of barium, calcium or the alka-
lies should be mixed with a mixture of lead chromate and
potassium pyrochromate which has been fused and pulverized.
This will decompose the metallic carbonate formed and expel
the carbon dioxide.
When the combustion of the substance is nearly finished the
current of gas passing into the potash bulbs will usually slaken
and the portion of the tube containing the boat may be brought to
full redness while the current of oxygen may be considerably in-
creased as the reduced copper is being reoxidized. At the same
time the flames under the reduced copper spiral should be low-
ered to prevent undue oxidation of the latter. Water sometimes
condenses in the front end of the combustion tube. This may be
driven on into the calcium chloride tube by very careful warm-
ing with a flame or by holding a hot tile from the furnace near
the tube. The current of oxygen is continued till it can be
detected with a glowing splinter at the end of the protecting
calcium chloride tube. It must then be displaced by dry air
ANALYSIS OF COMPOUNDS OF CARBONS 9
from the second gasometer, to avoid the error which would re-
sult if the calcium chloride tube and potash bulbs were weighed
full of oxygen instead of air. The passage of 300 to 400 cc. of
air will usually be enough. It is passed till a glowing splinter
no longer shows oxygen at the exit. Not more than one-half
liter to one liter of oxygen should be needed, if properly used.
The use of excessive amounts of oxygen or air is to be avoided.
When the operation is complete the calcium chloride tube and
potash bulbs are disconnected, protected at once with the rubber
caps, wiped as before and placed near the balance for an hour
before weighing.
The hydrogen is calculated from the weight of the water by
the factor 0.1119, the carbon, most easily by taking 3/11 of the
weight of the carbon dioxide.
For substances containing sulphur, lead chromate, fused and
granulated, is used in place of copper oxide. For substances
containing halogens a spiral of silver gauze or silver foil, heated
only moderately, is inserted in place of the reduced copper spiral,
or a boat containing reduced silver in the form of a powder may
be used.
Determination of Nitrogen by the "Absolute" Method
Literature. Johnson and Jenkins: Am. Chem. J., 2, 27; Schiff: Ber.,i3,
885; Bradley and Hale: J. Am. Chem. Soc., 3Q 1090.
For the determination of nitrogen by the absolute method
the substance is burned in a current of carbon dioxide, the
nitrogen is swept out into an azotometer filled with a solution of
potassium hydroxide and the nitrogen is measured.
The combustion tube may be prepared in exactly the same man-
ner (p. 6) as for the determination of oxygen and hydrogen, 1
though some prefer to seal the tube at the rear and put in that
end a layer of magnesite 15 cm. in length, followed by a copper
spiral, a layer of copper oxide, the substance mixed with copper
oxide, a long layer of copper oxide and the reduced copper
spiral.
1 A tube used for nitrogen should not afterwards be used for carbon and hydrogen,
unless it has been burned out in a current of oxygen.
IO ORGANIC CHEMISTRY
If an open tube of the same form used for the determination
of carbon and hydrogen is employed, the necessary carbon dioxide
may be generated by heating about 25 grams of acid sodium
carbonate in a hard glass tube protected by a sheet iron mantel.
Between the generating tube and the combustion tube a small bulb
tube of the form shown in Fig. 6 should be introduced to col-
lect the water which comes from the acid carbonate.
The carbon dioxide may also be generated in the apparatus
shown in Fig. 7. A is a 200 cc. Kjeldahl flask with a long neck.
In it are placed 20 grams of acid sodium carbonate and 50 cc.
of water. B is a separatory funnel having a long stem, all of it
below C of capillary tubing, except the bulb at D, which has a
Fig. 6.
capacity of 4-5 cc. This capillary tube should have an internal
diameter of not more than 2 mm. The separatory funnel should
contain 30 cc. of sulphuric acid (one part of concentrated acid
to one of water by volume) which should be drawn into it through
the capillary stem so that there will be no air below the stop-
'cock. The capillary stem of the funnel should not dip below
the surface of the solution and should be at least 30 cm. long to
furnish enough pressure so that the gases can be readily forced
through the combustion tube and into the azotometer. While the
front portion of the combustion tube is being heated the solu-
tion in the generator is boiled very gently for about 10 minutes,
causing a slow evolution of carbon dioxide, which will expel
the air from the water and flask. The exit tube is then closed
tightly with a short piece of rubber tubing and pinch-cock and the
ANALYSIS OF COMPOUNDS OF CARBONS
II
stop-cock of the separatory funnel opened very cautiously so that
the acid may drop in very slowly. As soon as the apparatus
is cooled a little the exit tube is connected with the bulb tube
(Fig. 6) and the latter to the rear end of the combustion tube,
Pig- 7-
into which the substance has meantime, been introduced in a
boat or bulb, as described for the determination of carbon and
hydrogen. The other end of the combustion tube is connected
with the azotometer shown in Fig. 8. The mercury in the lower
12 ORGANIC -CHEMISTRY
end of the azotometer should come about I cm. above the entrance
of the side tube through which the gases are delivered. The
potash solution is prepared by dissolving 100 grams of stick potash
in 160 cc. of water giving a solution which contains approxi-
mately 40 per cent, of potasium hydroxide. At this point in the
operation the stop-cock at the top of the azotometer is opened
and the bulb lowered so that nearly all of the potash solution is in
the bulb. While the front portion of the combustion tube is hot
Fig. 8.
and after all of the connections have been made as described, the
generation of a moderate current of carbon dioxide is continued
by dropping the acid into the generator very slowly during ten
or fifteen minutes. The potash solution is then brought to the
top of the azotometer, the stop-cock closed, the bulb lowered again
to reduce the pressure and the carbon dioxide entering the
azotometer examined to see if it is free from air and completely
absorbed by the potassium hydroxide. During this part of the
operation great care must be taken that the substance does not
become warm enough so that any of it volatilizes or decom-
ANALYSIS OF COMPOUNDS OF CARBONS 13
poses. If the test is satisfactory, then the combustion may be
carried out essentially as in the determination of carbon and
hydrogen. During the combustion the current of carbon dioxide
should be very slow indeed. It is continued till the portion of
the tube containing the substance has been heated to bright red-
ness and no more nitrogen passes into the azotometer. After
the combustion is completed the azotometer is placed in a room
of uniform temperature and the volume of the nitrogen is read
after half an hour or an hour. During this time the bulb con-
nected with the side tube should be brought to the level of the
top of the potash solution in the azotometer so that the gas will
be under atmospheric pressure and less likely to change its vol-
ume by leakage. It hardly need be said that the stop-cock must
be .carefully lubricated with a viscous lubricant. It is also well
to have a little of the potash solution in the tube above the
stop-cock.
The azotometer should be carefully calibrated. This may be
done by attaching to the lower end, at B, a rubber tube, pinch-
cock and delivery tip such as is used with a Mohr's burette.
The first two or three cubic centimeters at the top should be
calibrated with the burette filled with a potassium hydroxide so-
lution of about the same strength as that used in the analysis,
since the form of meniscus of such a solution is quite different
from that of pure water. The specific gravity of the solution
used must, of course, be known, accurately. For the rest of the
azotometer pure water may be used for the calibration, since it
is the value of the intervals between successive marks which is
required. For the calculation of the volume from the weights
of water see p. 33.
In reading the volume- of the nitrogen the level of the potash
solution in the bulb must be brought to the level of the top of
the solution in the azotometer so that the nitrogen will be at at-
mospheric pressure. At the time of this reading the pressure
of the air is determined by means of a barometer, whose reading
should be corrected to zero.
For a pressure of 760 mm. the correction which is to be sub-
tracted from the reading of the barometer is :
14 ORGANIC CHEMISTRY
Correction for Correction for
f glass scale brass scale
5 0.7 0.6
10 1.3 1.2
15 2.0 1.9
20 2.7 2.5
25 3-3 3-1
3 4-0 3-7
35 4-7 4-3
A change of 7.6 mm. in the pressure causes a change of one per
cent, -in the correction. Thus if the pressure read is 730 mm. at
25 the correction is to be diminished by 4 per cent, and becomes
3.2 for a glass scale. This secondary correction is too small to
be of practical importance for gases at atmospheric pressure.
The temperature is determined by means of a thermometer
placed beside the azotometer.
The weight of the nitrogen may be calculated by the formula :
Wt. in grams = 0.0012507 V X ^^ X
= 0.00449 V X
V = = Volume in cubic centimeters
/ = temperature of the gas
p Barometric pressure
p = Aqueous pressure of a 40 per cent, solution of
potassium hydroxide.
TABLE OF VAPOR PRESSURE
Aqueous pressure in millimeters of pure water and of a 40 per cent,
solution of potassium hydroxide 2
Pure 40 # Pure 40$ Pure 40*
1 H 2 O KOH t H 2 O KOH t H 2 O KOH
4.6 2.6 12 I0*.5 5.8 24 22.2 II.7
1 4-9 2 -8 13 II- 2 6.1 25 23.5 12.4
2 5-3 3- 14 ii. 9 6.5 26 25.0 13.1
3 5-7 3-2 15 12.7 6.9 27 26.5 13.6
4 6.1 3.4 16 13.6 7.4 28 28.1 14.7
5 6.5 3.6 17 14.4 7.8 29 29.8 15.5
6 7-0 3-9 l8 154 8.3 30 31.6 16.4
7 7-5 4-1 19 l6 -4 8.9 31 33.4 17.3
8.0 4.4 20 17.4 9.3 32 35.4 18.3
9 8.6 4.7 21 18.5 9-9 33 37-4 18.4
10 9.2 5.1 22 19.7 10.5 34 39.6 20.5
11 9-8 5-4 23 20.9 ii. i 35 41.9 21.5
1 The fraction would be more accurate, as nitrogen is not an ideal gas, but
the error of the usual formula is only one part in 1300 at 25.
2 Prepared by interpolation from the Landolt-Bernstein-Meyerhoffer Tabellen, pp.
71 and 723.
ANALYSIS OF COMPOUNDS OF CARBONS 15
REDUCTION OF CUBIC CENTIMETERS OF NITROGEN TO GRAMS
s (l + 0.003676)760
/
0.0
O.I
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
"21634
618
60 3
587
57i
555
539
523
507
491
I
475
459
443
427
411
396
380
364
348
332
2
3i6
300
284
268
252
236
221
205
I8 9
i/4
3
158
142
127
in
095
079
064
048
032
017
4
OOI
986
970
954
939
-923
-907
-892
-876
860
5
6*20844
829
813
798
' 782
767
751
735
719
703
6
687
672
656
641
625
609
594
578
563
547
7
531
5i6
500
484
469
453
437
422
406
39i
S
375
360
344
329
313
298
282
267
251
236
9
221
205
190
174
159
143
128
112
097
082
10
066
051
035
020
005
-989
-974
- 9 68
-943
928
II
"19913
897
882
86 7
852
836
821
806
791
776
12
759
744
729
7H
699
684
679
653
638
623
'3
607
592
577
562
547
53i
5i6
501
486
47i
M
455
440
425
410
395
380
365
350
335
320
15
34
289
274
259
244
229
214
I 99
184
169
16
153
138
123
108
093
078
063
048
033
018
17
002
-987
972
-957
942
927
912
-897
882
-867
18
"18852
837
822
807
792
777
762
747
732
7i7
r 9
703
688
673
658
643
628
613
598
583
568
20
553
538
523
508
493
478
464
449
434
419
21
405
39
375
360
345
33i
3i6
301
286
271
22
257
242
227
213
198
183
168
154
139
124
23
109
095
080
066
051
036
02 1
007
992
977
24
"17962
947
932
918
903
888
874
859
845
830
25
816
80 1
786
772
757
742
728
713
699
684
26
670
655
641
626
612
597
583
568
554
539
27
524
5to
496
481
467
452
438
423
409
394
28
379
364
350
335
321
306
292
2/8
263
249
29
235
220
206
191
177
163
148
134
119
105
30
091
077
063
048
034
020
005
991
977
-962
3i
"16947
933
919
904
889
875
86 1
847
833
819
32
804
790
776
762
747
733
719
704
690
675
33
66 1
647
633
6i9
604
590
576
562
548
534
34
519
505
491
477
462
448
434
420
406
392
1 From Frankland's Water Analysis, corrected for the modern values for the weight
and coefficient of expansion of nitrogen.
i6
ORGANIC CHEMISTRY
The accompanying table will be found more convenient foi- the
calculations. Add together the logarithm corresponding to the
temperature taken from the table, the logarithm of the volume
and the logarithm of (P p). The sum will be the logarithm
of the weight of nitrogen in milligrams.
WEIGHT OF NITROGEN IN ONE CUBIC CENTIMETER OF THE
GAS MEASURED OVER WATER
If the gas is measured over a 40 per cent, solution of potassium hydroxide,
add to the barometric reading the difference between the aqueous pressure
of pure water and that of the potassium hydroxide solution at the given
temperature. The table is based on 1.2507 as the weight of one cubic centi-
meter of dry nitrogen at o and 760 mm.
tP 721 724 727 730 733 736 739 742 745
10 1.130 1.135 1.139 1.144 1.149 I - I 54 1-158 1.163 1-168
11 1.125 1.129 1.134
12 I.I2O I.I24 I.I29
13 I.H5 T.II9 LI24
14 i.uo 1.114 1.119
15 I.I05 I.I09 I.II4
16 1.099 I - I 3 I - 2 8
17 1.094 1.098 1.203
18 1.089 1.093 1.098
19 1.084 1.088 1.093
20 1.079 1.083 i. 088
21 1.074 1.078 1.082
22 1. 068 1.072 1.076
23 I.O62 1.067 I.O7I
24 I.O57 1 .06 1 1. 066
25 I.05I 1.056 1. 060
26 1.056 1.050 1.054
27 1.040 1.044 1.048
28 1.034 1.038 1.042
29 I.O28 I.O32 1.036
30 1.022 1.026 I.03I
31 I.OI5 I.O2O I.O24
32 1.009 LOI4 I.OlS
33 1.003 1.008 i. 012
34 0.996 i.ooi 1.005
35 0.990 0.995 0.999
1.139
1. 144
I.I48
I-I53
1.158
1.162
1.134
I - I 39
I.I43
I.I48
1. 153
I-I57
1.129
I-I34
I.I38
1. 143
1.148
I.I52
1.124
1.129
I-I33
I.I38
I.I43
I.I47
1.119
1.124
I.I28
I.I33
1.138
I.I42
1.113
1.118
I.I23
I.I27
1.132
I.I37
1.108
1.113
1.118
I.I23
1.128
1.132
1. 102
1.107
1. 112
1.116
1. 121
I.I25
1.097
I.IO2
I.IO7
i. in
1.116
1. 120
1.092
1.097
1. 102
1.106
I. HI
I.H5
1.087
I.O9I
1.096
I.IOI
1.106
I. HO
I.oSl
1.086
I.09I
1.095
I.IOO
I.I04
1.076
I.OSO
1.085
1.090
1.094
1.098
I.O7I
1.075
1. 080
1.084
"1.089
1.093
1.065
1.069
1.074
1.078
1.083
1.087
1.059
1.064
1.068
.072
1.077
1.082
1.053
1.058
1.062
.066
1.071
1.076
1.047
1.052
1.056
.060
1.065
I.O7O
I.04I
1.046
1.050
.054
1-059
1.063
1.035
1.040
1.044
.048
1.053
1-057
I.O29
1.033
1.038
1.042
1.046
I.05I
1.022
1.027
1.032
1.036
1.040
1.044
1.016
I.02[
1.026
1.030
1.034
1.038
I.OO9
I.OI4
1.019
1.023
1.027
I.03I
1.003
1.008
1. 012
1.017
I.O2I
1.025
ANALYSIS OF COMPOUNDS OF CARBONS
(P
10
WEIGHT OF NITROGEN IN ONE CUBIC CENTIMETER OF THE
GAS MEASURED OVER WATER ( Continued)
748 751 754 757 76o 763 766 769 772
I.I73 LI77 Ll82 I.l87 LI92 I.I97 1.202 1. 206 1. 211
I.I76
11 I.I67 LI72
12 I.I62 1.167 I.I7I
J 3 I - I 57 1.162 1.166
14 1.152 1.157 1.161
15 1.147 1.152 1.156
16 1.141 1.146 1.150
17 1.136 1.140 1.144
18 1.130 1.135 1.139
19 1.125 1.130 1.134
20 1. 120 I.I25 LI29
21 I. 114 I.II9 I.I23
22 I.IOS I.II3 I.H8
23 I.I03 I.I07 I- HI
24 1.097 i.ioi 1.106
25 1.092 1.096 i.ioi
26 1.086 1.090 1.095
27 1.080 1.084 1.089
28 1.074 1.078 1.083
29 i. 068 1.072 1.077
30 1.062 i. 066 1.971
31 1.056 i. 060 1.064
32 1.049 1-053 1-158
33 1.043 1.047 1.051
34 1.036 1.040 1.044
35 1.030 1.034 1.038
I
.181
.186
.191
i
I
.176
.181
.186
i
I
.171
.176
.181
i
I
.166
.171
176
i
I
.161
.166
.170
i
,
155
1.160
.164
,
I
.149
I-I54
.158
i
I
.144
1.149
!53
i
I
139
1.144
.148
i
1
134
1.138
M43
x
I
.128
I-I33 ]
[.138
i
I
.123
1.127
[.132
i
I
.116
1. 121
[.126
i
I
.in
1.116
[.121
i
r
.105
i. no
MIS
i
i
.099
1.104
[.108
i
r
093
1.098
[.102
i
i
.087
1.092
[.096
i
i
.081
i. 086
[.090
i
i
075
1.080 ]
[.084
i
i
.069
1.073
[.078
i
f
.062
1.066
[.071
j
i
055
1.059
[.064
i
i
.049
1-053
[.058
i
i
.043
1.047
1.051
i
.196 I.2OO I.2O5
.190 1.195 I.I99
I.l85 I.I90 1.194
I.lSo I.I85 1.189
I.I75 I.lSo I.l84
69 I.I74 I.I78
1.163 1.167 I.I72
I.I58 I.l62 I.l67
I.I53 LI57 1-162
1.148 1.152 1.157
1.142 1.147 1-151
1.136 1.141 1.145
131 1.136 1.140
125 1.130 1.134
1.119 1.124 1.129
I.II3 I-II7 1. 122
1.107 i. in 1.116
i.ioi 1.105 i. no
1.095 1.099 LI04
1.089 L093 1.098
1.082 1.087 1.092
1.076 1.080 1.085
1.069 I '74 i.79
1.063 1.067 1.072
1.056 i. 060 1.065
Not quite so accurate but still sufficiently so far all ordinary
purposes is the table giving the weight of nitrogen in one cubic
centimeter of the gas measured over water at different tempera-
tures and pressures. The table may also be used for nitrogen
measured over a solution of potassium hydroxide but for this
purpose there must be added to the observed barometric pres-
sure the difference between the pressure of water vapor for pure
water and for the g ; ven solution. Thus the weight of the nitro-
l8 ORGANIC CHEMISTRY
gen in one cubic centimeter of the gas measured over 40 per cent,
solution of potassium hydroxide at 25 and 751 mm. barometric
pressure is 1.113 mg. while if measured over pure water it is
1.096. The error of calculation in using this table will not, in
most cases, exceed one part in 1,000. The values obtained by
means of some similar tables in common use are about one part
in 250 too high, because the tables are based on the old, erroneous
value for the weight of one cubic centimeter of nitrogen.
Determination of Nitrogen by the Kjeldahl Method
Literature Kjeldahl: Z. anal. Chem., 22, 366; Gunning: Ibid, 28, 188;
Foerster: Ibid, 28, 422; Kober: J. Am. Chem. Soc., 30, 1131; Gill and
Grindley: Ibid, 31* 1249; Kober: Ibid f 32, 689.
The nitrogen of amides, amines, proteins and of some other
compounds may be determined by the Kjeldahl method, which con-
sists in digesting the substance with hot, concentrated sulphuric
acid, usually with the addition of some substance to aid in the
oxidation, followed by dilution, neutralization and distillation of
the ammonia from the alkaline solution. The nitrogen of nitro
compounds and of nitrates may be determined by the same meth-
od, after previous reduction.
Place in a 300 cc., long necked, Kjeldahl flask, best of Jena
glass, 0.2 to 0.5 gram of the substance to be analyzed, add 20 cc.
of pure concentrated sulphuric acid, 10 grams of potassium sul-
phate and 0.5 gram of mercury. 1 The mercury is best measured
in a very small capillary tube, having a mark on it to indicate
the quantity which should be taken. Support the flask at an
angle of 45 and heat the contents over a low flame, applied
directly to the glass, for one to two hours. The contents of the
flask should boil gently but not so rapidly that much sulphuric
acid escapes from the mouth of the flask. The operation must,
of course, be carried on in a hood with a good draft. If the
contents of the flask does not become colorless at the end of
two hours, the oxidation may be finished by adding carefully
a small amount of potassium permanganate.
1 Some chemists use o.i gram of crystallized copper sulphate instead of mercury. In
that case the subsequent use of potassium sulphide is not necessary.
ANALYSIS OF COMPOUNDS OF CARBONS IQ
Measure into a 300 cc. Erlenmeyer flask an amount of N/io
hydrochloric acid about ten per cent, in excess of that required
to neutralize the ammonia expected from the quantity of sub-
stance taken, (i cc. of K/io hydrochloric acid is equivalent to
1.4 mg. N). Arrange a distilling apparatus as shown in the
figure, the connection with the Kjeldahl flask being made by
Fig. 9.
means of a Hopkins distilling bulb. The condenser tube is best
of tin or aluminum. The bulb tube connected to the lower end
of the condenser should dip under the surface of the standard
acid. When the contents of the digestion flask is cooled suffi-
ciently, add 150 cc. of water and cool again, then pour care-
fully down the side of the flask, so that it will run to the bot-
tom without mixing, 80 cc. of a solution containing 30 grams
of sodium hydroxide and 2 grams of potassium sulphide. Add
two or three pieces of granulated zinc. Connect at once with
20 ORGANIC CHEMISTRY
the distilling tube, mix the contents of the flask by careful shak-
ing and distil over 125-150 cc. Titrate the excess of acid with
standard alkali, using methyl orange or congo red or methyl red
as indicator.
A blank experiment should be carried out with the same
quantities of all the reagents, except that only i to 2 cc. of
the standard acid should be used. Any nitrogen found in the
blank determination is to be subtracted from the amount found
in the analysis.
Instead of distilling the ammonia as described it may be
aspirated over into the standard acid by Kober's method.
Determination of Halogens, Sulphur or Phosphorus by
Carius's Method
Literature C'arius : Ber., 3, 697 ; Kiister : Ann., 285, 340 ; Walker and
Henderson: Chem, News, 7 1 * 103.
Prepare a tube of glass designed for sealing tubes (the
"Einschmelzrohren" of Schott and Genossen are excellent) hav-
ing an inner diameter of 14-16 mm. walls 2 mm. thick and a
length of 35-40 cm. Seal very carefully at one end, taking
care that the walls fall together somewhat during the sealing
and that no portion becomes thin. Introduce one-half a gram
of silver nitrate and 1-1.5 cc - f P ure nitric acid of sp. gr. 1.50
(not the red fuming acid). The amount of acid should be 20
per cent, in excess of that required for the complete oxidation
of the substance on the supposition that it is reduced to nitrous
acid. A larger amount of acid is not necessary and increases
the danger of explosion. Introduce the substance, weighed in
a small tube, 2-3 cm. long and 6-8 mm. in diameter. Seal the
other end of the tube carefully, drawing it out very slowly to
prevent the wall from becoming thin at any point and having
at the end a capillary tip 4-6 cm. long and with " an internal
diameter near the end of ^ mm. or less. Place the tube in
a bomb furnace, rais'e the temperature slowly to 320 and keep
it at 3io-33O for two hours. It need hardly be said that the
furnace must be so placed with the ends protected by iron or
heavy wooden shields that no one can be injured in case of an
ANALYSIS OF COMPOUNDS OF CARBONS
explosion. Where the furnace is thoroughly cold, remove the
tube very carefully always keeping several thicknesses of a
towel or heavy cloth between the tube and the 'hand or body
and wrapping it well in a towel as soon as it is removed from
the furnace. A better method, which should always be used
when possible, is -to have a furnace with movable iron tubes and
to keep the sealed tube almost entirely in the iron tube until
the pressure has been relieved by holding the tip in the flame
of a burner till the internal pressure has blown out an opening.
During this operation the tube is held with the end bearing
the capillary tip high enough so that the contents of the tube
will run to the lower end. The eyes should be protected by
goggles. After the pressure has been relieved the end of the
tube is cut off and the silver halide is carefully rinsed out into
a small beaker. If some of the silver halide can not be removed
from the tube by rinsing, it may be dissolved in a very little am-
monia and the solution added to the contents of the beaker. In
such a case the solution in the beaker must stand in the dark
till the precipitate has settled before filtering. In the case of
silver iodide or bromide it is advisable to digest the solution
and precipitate on the water-bath for a short time to decom-
pose double compounds which are 'formed with the excess of sil-
ver nitrate. The solution is filtered on a Gooch crucible, the
precipitate washed and finally dried at I5O-2OO.
For the determination of sulphur or phosphorus the addition
of silver nitrate is omitted and the sulphuric or phosphoric acid
in the diluted oxidation mixture is determined by the usual
analytical methods with use of barium chloride or molybdic mix-
ture.
Determination of Halogens or Sulphur by Pringsheim's Method
Literature. Pringsheim : Am. Chem. J., 31, 386; Ber., 36, 4244;
Schreiber: J. Am. Chem. Soc., 3 2 977-
About 0.2 gram of the substance is mixed with sodium per-
oxide in a brass or steel crucible of the form shown in Fig. 10.
If the substance contains 75 per cent, of carbon and hydrogen.
22
ORGANIC CHEMISTRY
18 times its weight of the peroxide should be used. If it contains
50 to 75 per cent, of carbon and hydrogen, 16 times its weight
should be used; if it contains 25 to 50 per cent, it should be
mixed with, half of its weight of sugar and if it contains less
than 25 per cent, it should be mixed with an equal weight of
sugar, the amount of peroxide being in the former case 16 times
and in the latter caseviS times the weight of the mixture. For
practically all cases a stock mixture of one part of sugar with
25 parts of sodium peroxide may be prepared and one part
of the substance to be burned mixed with 30-32 parts of this
Fig. 10.
mixture. The sugar and substance must be finely powdered, the
latter, of course, before weighing. They are intimately mixed with
the sodium peroxide in the crucible by means of a small nail, which
is left in the crucible during the ignition. The cover is placed on
the crucible and the latter is immersed in distilled water in a porce-
lain dish to within 3 or 4 mm." of its upper edge. The mix-
ture is ignited by thrusting a red hot iron wire through the hole
in the lid. If the mixture ignites very rapidly with the evolu-
tion of considerable gas, and smoke and flame appear through
the nail hole in the lid, too much carbonaceous matter has been
used. If the mixture fails to ignite throughout, too much so-
dium peroxide has been taken. In either case it is best to repeat
ANALYSIS OF COMPOUNDS OF CARBONS 23
the ignition, though, if the sample is valuable it can be saved
in the second case by completing the ignition over the blast.
When the reaction is complete, the crucible is turned on its side
and the contents of the dish warmed gently till solution is com-
plete. The solution is then filtered, 5 cc. of a strong solution of
sodium sulphite added to reduce any oxygen acids of the halogens
which may have been formed, and then dilute sulphuric acid to
strongly acid reaction. The halogen acid may be precipitated
in the usual manner with silver nitrate or it may be titrated by
Volhard's method. In the latter case an excess of silver nitrate
should be added either before or immediately after acidifying and
the solution boiled to expel sulphur dioxide before titrating
back with the thiocyanate. Also, if chlorine is to be determined,
the silver chloride must be filtered off before titrating (RosanofF
and Hill: J. Am. Chem. Soc., 29, 269). Sulphur and phosphorus
may also be determined by burning the substance with sodium
peroxide followed by precipitation from the acidified solution.
The method is not adapted for use with liquids.
Determination of Halogens by Reduction with Sodium and
Absolute Alcohol
Literature. Stepanow : Ber., 39, 4056; Bacon: J. Am. Chem. Soc., 3',
49-
For liquid substances and substances which ignite on. mixing-
with sodium peroxide the method of Stepanow is very suitable. In-
troduce into 150 cc. Kjeldahl flask 0.2 gram of the substance to be
analyzed and 35 cc. of absolute alcohol (98 per cent, at least) if
it contains chlorine, 18 cc. if it contains bromine or 13 cc. if it
contains iodine. Connect the flask with an upright condenser,
support it on a thin sheet of asbestos on a wire gauze, warm
gently till the substance is dissolved and. add gradually, during
at least 30 minutes, through the condenser, 3.5, IJT, or i.i grams
of sodium according as the substance contains chlorine, bromine
or iodine. Toward the end keep the solution boiling gently with
a burner and boil the solution for one hour after the sodium
is all dissolved. Allow the solution to cool to 50 or 60, add,
cautiously, 50 cc. of water through the condenser, cool, acidify
24 ORGANIC CHEMISTRY
with nitric acid, add an excess of standard silver nitrate, filter,
if the halide is chlorine (Rosanoff and Hill: J. Am. Chem. Soc.,
29, 269), add ferric sulphate and titrate with a standard solution
of ammonium thiocyanate by Volhard's method.
Determination of Barium, Strontium, or Calcium in Salts of Or-
ganic Acids. Weigh 0.2 to 0.3 gram of the salt in a platinum
crucible and heat in an air-bath for I to 2 hours at 100 to 200
according to the nature of the salt. In the case of salts of un-
known properties, it is safest to dry to constant weight in a vac-
uum desiccator first, then successively at 100, 135, -175 afl d
200, noting at which temperature a constant weight can be ob-
tained without decomposition. After determining, as above,
water of hydration, if present, add to the salt one or two
drops of concentrated sulphuric acid and heat very gently over a
low flame till fumes of sulphuric acid cease to escape, then at
faint redness till the sulphate formed is pure white. Cool and
weigh, then moisten with a drop of concentrated sulphuric acid
and heat very gently till the acid is expelled and finally again to
faint redness. If the contents of the crucible increases in weight,
the presence of a little sulphide at the end of the first heating
is indicated and the second weight is to be taken. In calcium
salts the metal may be determined as calcium oxide by direct
ignition over the blast lamp.
Determination of Sodium, Potassium or Other Metals. Sodium
and potassium may be determined as sulphates by ignition with
sulphuric acid as described above but the temperature of the
crucible must never be above dull redness for fear of volatiliz-
ing some of the salt. Also, after the salt is pure white, some
solid ammonium carbonate should be thrown into the crucible
several times and the heating continued to convert any acid sul-
phate present into the neutral salt.
In silver salts the silver may be determined as metallic silver
by gentle ignition in a porcelain crucible.
Chapter II
GENERAL OPERATIONS
The most important general operations used in the prepara-
tion of pure substances are separation by means of solvents, ex-
traction witn ether or other immiscible solvents (p. 167, 54), crys-
tallization (p. 129), fractional crystallization (p. 122), fractional
distillation, distillation under diminished pressure (p. 172), dis-
tillation with steam (p. 71), sublimation (p. 80), filtration
(p. 120), and determination of the melting-point, boiling-poirjt
and specific gravity. In this chapter only fractional distillation,
the determination of the boiling-point, the determination of the
melting-point and the determination of specific gravity will be
considered. The other operations will be discussed in connec-
tion with preparations in which they are used.
At the close of the chapter directions for the distillation of
wood and separation of the various products formed are given
as an illustration of a number of operations common both in the
laboratory and in technical processes.
1. Fractional Distillation and the Determination of Boiling-
points. Carbon tetrachloride and aniline.
Literature Theory of fractional distillation; Nernst: Theoretische
Chemie, 6th Edition, p. in; Noyes : Organic Chemistry, p. 13; Correction
of thermometers; Crafts: Am. Chem. J., 5 324; Circular of the Bureau
of Standards Washington ; Rimbach : Ber., 22, 3072 ; Apparatus for frac-
tional condensation; Hahn : Ber., 43 419; C. A., IQ, 1168; Prevention
of bumping, Scudder: J. Am. Chem. Soc., 25, 163; H. Meyer: Analyse
und Konstitutionsermittelung org. Verbindungen, 2, Auf 1. pp. 46-47 ;
Determination of boiling-point of a small amount of substance; Mulli-
ken: A Method for the Identification of Pure Organic Substances, p.
222; Alex. Smith and Menzies : J. Am. Chem. Soc., 32, 897; See also p
269.
25 grams aniline.
25 grams carbon tetrachloride.
Place 25 grams of carbon tetraohloride in a 50 cc. flask con-
26 ORGANIC CHEMISTRY
taining 5 grams of powdered calcium chloride. In a second
flask of the same size place 25 grams of aniline with 5 grams
of powdered potassium hydroxide. After an hour, or better
after standing over night, filter one of the liquids through a dry
filter into a 50 cc. distilling bulb and distil slowly with the ap-
paratus shown in the figure. The thermometer is held in place
by a tightly fitting, sound and carefully bored cork, not a rub-
ber stopper. It is usually best to make the hole with a cork-borer
a little smaller than the thermometer and enlarge it by means of a
round file. The bulb of the thermometer must always be placed
a little below the side tube of the distilling bulb but should never
Fig. ii.
be placed within the liquid or too close to it. The condensing
tube for the present case may be about I cm. in internal diameter
and 60 cm. long. For more volatile liquids than carbon tetra-\
chloride or for the rapid distillation of larger amounts of sub-
stance a Liebig's condenser should be used. The condensing
tube may be drawn out at the upper end so that the side tube of
the distilling bulb will just enter it and connected with the latter
by slipping a tightly fitting rubber tube over both. The distill-
ing bulb is to be heated over a low flame applied directly to
the bulb. A micro burner, if available, is most satisfactory for
the purpose when a small quantity of liquid is to be distilled.
Collect the first portion of the distillate in a dry test tube till the
thermometer indicates a temperature within i of the boiling-
GENERAL OPERATIONS 27
point (76.7 for carbon tetrachloride, 183.7 for aniline), then
collect the principal portion, which should boil within an in-
terval of two degrees, in a small dry, weighed flask.
A small additional amount, boiling within the proper interval
may usually be obtained by redistilling the portions collected
below and above the interval chosen.
Having determined the weights 1 of carbon tetrachloride and
aniline obtained, mix them together and subject the mixture to
fractional distillation collecting the successive fractions in a se-
ries of dry flasks or, for the smaller fractions, of test-tubes,
labelling each with a gummed label marked with a pencil, or
with a pencil which will write on glass. Eight or ten fractions
should be collected, the temperature intervals being chosen with
reference to the amounts of the distillates at different tempera-
tures. The use of good common sense as to the amount which
should be collected in each fraction and the corresponding tem-
perature intervals to be chosen is one of the most important points
in fractional distillation. In general, the fractions should be
larger, and the temperature intervals also shorter, at points near
the boiling-points of the substances to be separated.
When the whole has been distilled the apparatus is carefully
cleaned and dried and the lowest boiling fraction returned to the
bulb. This is then distilled and the first distillate collected
in the same flask but for a much narrower interval of tempera-
ture than before, a second portion being collected in a new
receptacle. When the lower temperature for the second fraction
from the first distillation is approached that is added to the
bulb through a small, dry, funnel, and the distillation continued,
the distillate being collected, of course, in the proper flask or tube
corresponding to the boiling-point. While the intervals of tem-
perature in the neighborhood of the boiling-points of carbon
tetrachloride and of the aniline should be shorter on the second
distillation the intervals between may be lengthened, so that the
total number of fractions is not increased. If a considerable
portion is obtained boiling within an interval of two degrees of
the boiling-points of carbon tetrachloride and aniline respectively,
1 Weigh roughly within o.i to 0.2 gram.
28 ORGANIC CHEMISTRY
those fractions need not be distilled again but the intermediate
fractions may be distilled once more to increase the amounts
of these two principal fractions. Weigh these two fractions and
determine the percentage yield.
The slow distillation, which the air conjdenser makes necessary
to avoid loss of carbon tetrachloride, conduces to a better separa-
tion, and, in general, distillation should not be conducted too
rapidly in fractioning. A general rule is that the liquid should
drop from the end of the condenser at the rate of two drops
a second. The neck of the flask should always be placed over
the end of the condensing tube to prevent loss by evaporation.
With volatile or hygroscopic liquids the space between the con-
densing tube and the neck of the flask should be closed with cot-
ton or with a cork having a V shaped piece cut from its side to
allow escape of air.
When substances differing but little in their boiling-points are
to be separated a Laenburg distilling bulb (p. 172) a Hempel tube
filled with glass beads (p. 36) or a Hahn fractioning head (loc.
cit.) may be used to advantage.
If the thread of the thermometer is not entirely immersed in
the vapor, a correction must be added to its reading. This may
be taken from Rimbach's table or calculated by the formula:
Cor. = + N(* 00.000154.
N = Number of degrees on the stem of the thermometer
below the temperature read.
t = temperature read.
t f = Average temperature of the stem.
0.000154 Coefficient of apparent expansion of mercury in
glass.
The thermometer must also be tested to determine if it reg-
isters correctly. This is best done by means of the boiling-
point of some pure substance which boils near the boiling-point
to be determined. Suitable substances for this purpose are:
Ethyl ether 34.6
Water 100
Ethvlene bromide 130.3
Aniline 183.7
Naphthalene 218.1
Benzophenone *. 306.1
GENERAL OPERATIONS 29
For the last two the boiling-points under varying pressures
have been accurately determined. Crafts : Am. Chem. J., 5, 324.
In case the pressure of the air is greater or less than 760 mm.
a correction must be applied. For liquids which do not as-
sociate, when the pressure is not far from 760 mm. the cor-
rection for a difference of 10 mm. in the pressure may be found
by dividing the absolute temperature of the boiling-point by
850. For associative liquids, as alcohols, acids and hydroxyl
compounds generally, the factor is 1020. (Alex. Smith and
Menzies: J. Am. Ch. Soc., 32, 907.) The following table cal-
culated on this basis will be found convenient.
Boiling-point ^-Correction for a difference of lomm. in the pressure .
(Ordinary scale) For non-associating liquids For alcohols, acids, etc.
50 0.38 0.32
100 0.44 0.37
150 0.50 0.42
200 0.56 0.46
250 0.62 0.5I
300 0.68 0.56
350 0.74 0.6 1
400 0.80 0.66
By using a set of Anschiitz thermometers, each of which
has a range of only 60 to 70, the correction for the stem may
be made very small and usually may be neglected.
2. Determination of Melting-points. Urea, phthalic anhydride,
/-toluidine.
Literature. Apparatus, Scudder: J. Am. Chem. Soc., 25, 161 ; Thiele:
Ber., 40, 996; Correction for thermometers, Crafts: Amer. Chem. J., 5>
324; Rimback: Ber., 22, 3072.
The purity of solid substances is, in many cases, most easily
tested by means of the melting-point. For this purpose the
substance must be perfectly dry. The drying can be effected
by allowing the body to lie for a sufficient length of time on
filter-paper, or on clean, porous porcelain, best over sulphuric
acid in vacua.
A lot of capillary tubes for the determination of melting-
points may be prepared by taking a soft glass tube with not
too thin walls, 4 to 5 mm. in external diameter, and drawing
3O ORGANIC CHEMISTRY
it out as indicated above. (See Fig. 12.) The tube is then
Fig. 12.
sealed off near each bulb, and the closed tubes kept till needed.
For use, the bulb is cut in two by scratching with a file and
breaking. 1 The finely powdered substance is put into the
wide end of the tube and shaken down, or pushed down
to the point with a clean platinum wire. For a melting-
point bath the best for general use is a round-bottomed, 75 cc.
flask, with a rather long neck. In the mouth is placed a stopper,
perforated so that the thermometer will pass easily through it,
and be held in place by a small wooden wedge, e.g., a
match stick. Through the side of the cork passes a
small platinum wire with loops, as indicated in the figure.
(See Fig. 13). If moistened with the sulphuric acid,
the tube will adhere to the thermometer by capillary
attraction, but such an arrangement is less secure. Ihe
part of the capillary tube containing the substance should
lie in contact with the bulb of the thermometer. The
bath may be heated rapidly with a free flame till the
temperature approaches the melting-point, and then very
slowly. In case of bodies which decompose at or near
their melting-points, the thermometer and the tube should
be brought as quickly as possible, without danger of
Fig. 13. breaking the thermometer, into the hot bath and the
latter brought quickly to the melting-point. The result, in such
cases, cannot be very accurate.
When, as is usually the case, the stem of the thermometer is
not immersed in the sulphuric acid to the point to which the
mercury rises, a correction similar to that for boiling-points
must be applied. (See p. 28.)
In general, a sharp melting-point, within an interval of one
degree, at most, is characteristic of a pure substance, while im-
pure substances melt indefinitely.
1 Some chemists prefer thin, straight capillary tubes prepared by drawing out a test-
tube. The tube should be about the size of the lead of a lead pencil.
GENERAL OPERATIONS 3!
Instead of the bulb, shown in Fig. 14, the Thiele apparatus
Fig. 14.
shown in Fig. 15 may be used to advantage. For temperatures be-
Fig. 15.
low 300 concentrated sulphuric acid may be used in the bulb or
apparatus but a mixture of 7 parts of acid with 3 parts of po-
tassium sulphate gives off less of acid vapors and may be heated
to a higher temperature without boiling. A mixture of 6 parts
of acid with 4 parts of potassium sulphate may be used to a
temperature of 365 but becomes pasty or solid at ordinary
temperatures. For still higher temperatures zinc chforide may
32 ORGANIC CHEMISTRY
be used but this must be poured into a shallow dish to solidify,
as it expands on crystallizing and would burst the bulb. If
the sulphuric acid darkens after using for some time, it may be
cleared by adding a fragment of potassium nitrate.
3. Determination of Specific Gravity. Specific gravity of
alcohol.
Literature Circular No. 9, Bureau of Standards, Washington, Test-
ing of Glass Volumetric Apparatus; Circular No. 16, Testing of Hy-
drometers; Circular No. 19, Standard Density and Volumetric Tables;
Traube: Physikalisch-Chemische Methoden, pp. 12-24; Ostwald-Luther :
Hand und Hilfsbuch zur ausfiihrung Physiko-Chemischer Messungen,
2nd Edition, pp. 141 ; Morley : Alcoholometric Table, J.. Am. Chem. Soc .
26, 1185; A new, more accurate table will soon be issued by the Bureau
of Standards.
Prepare a small bulb by drawing out a tube with a diameter of
I cm. and wall about I mm. thick to the form shown in the
Fig. 1 6. It should be drawn out in such a manner that the
\ /
A V
B
Fig. 16.
tube does not become too thin at A and that the internal diameter
at that point is about 2 mm. Then seal the tube at B and form
a. flattened end leaving a capacity of about I cc. Anneal the
bulb carefully in the flame, cool, cut the tube off about ^ cm.
above the narrowest point, round the cut edge in the flame and
make a narrow mark at A, using a moistened file, .best moistened
with a solution of camphor in turpentine. (A file moistened
with this mixture will cut or bore glass rapidly.) Clean the
bulb carefully with alcohol, introducing it and removing it with
a tube drawn out to a capillary of such size that it will pass
through the neck of the bulb. Warm the bulb gently and dry
it by drawing air through it with the same capillary tube. Cool
for half an hour in the balance case and weigh accurately. Fill
the bulb with water to a point just above the mark, using
the same tube as before. Bring the water in a 500 cc. beaker
OPERATIONS 33
exactly to 20. Place the bulb in. the water, supporting it with
a shelf so placed that the water comes to a point just below the
neck of the bulb. After ten minutes bring the liquid in the
bulb exactly to the mark by drawing out the excess with the
capillary pipette. Wipe the bulb dry and weigh after half an
hour. The weight of the water multiplied by 1.00282 will give
the volume of the bulb in cubic centimeters. 1 The volume at
15 will be, for a capacity of I cc., 0.00012 cc. less and at 25
0.00012 cc. more than at 20, owing to the contraction, or
expansion of the glass. Remove the water, fill the bulb with
alcohol, remove this and repeat twice, then dry as before. Fill
the bulb with alcohol, set it in the beaker of water, and repeat
the operations exactly as before. To the apparent weight of the
alcohol there must be added 0.00109 gram for each cubic centi-
meter in the capacity of the bulb, to correct for the buoyancy of
the air. The specific gravity referred to water at 4 will, of
course, be the corrected weight of the alcohol divided by the
volume, in cc., of the bulb.
It is always desirable to know the specific gravity of a new
substance at two different temperatures. For this purpose the
capacity of the bulb may be calculated at 15 and at 25 by the
rule given above. The bulb may be filled with alcohol at 15 or
25 by keeping the water in the beaker at the desired tempera-
ture. To the apparent weight must be added o.ooin gram at
15 or 0.00107 gram at 25 for each cc. as the correction to a
vacuum.
Unless it is desired to determine the specific gravity to the
fifth decimal, the value o.oon may be used for the corrrection at
pressures above 750 mm. or o.ooio at pressures of 700 to 750
mm.
A higher degree of accuracy may be obtained by the use of
a larger pyknometer but this is useless unless the liquid examined
is of a very high degree of purity. Determine the strength of
the alcohol by weight and by volume with the use of Mor-
ley's table, (loc. cit.)
1 One gram of water at 20 fills a volume of T. 001768 cc. and one gram of water as indi-
cated by brass weights is really 1.001053 gram, when corrected for the buoyancy of the air.
3
34
ORGANIC CHEMISTRY
4. Distillation of Wood.
Literature J. Anal and Appl. Chem., 5> 241 ; Met. and Chem. Eng., 8,
I55 433- F r acetone see also 33i p. 92.
1,200 grams of wood.
Put 1,200 grams of wood, cut into billets about an inch
square into the iron retort shown in Fig. 17. The retort is of
Fig. 17.
..
cast iron, 15 cm. inside diameter and 20 cm. deep, with walls
12 mm. thick. It is fitted with a thermometer, reaching well
down into the charge of wood and with a glass delivery tube.
Both the thermometer and delivery tube should pass through
carefully bored, tightly fitting cork stoppers. The cover of the
retort is held on with iron dogs and wedges, a thin sheet of as-
bestos being interposed between the cover and the body of the
retort to insure a tight joint. 1 The retort is supported by a
piece of thick asbestos board bent to the proper shape and held
in place with wire. Openings are cut in the board above and
below for the entry and exit of air and the retort is heated by
a good triple burner.
1 Instead of the retort described, the one shown in Fig. 17 A may be used. This is 60 cm.
long and 7.5 cm. in diameter, with walls about 6 mm. thick. There is a 2.5 cm. flange at
the end ground smooth and fitted with a perforated iron plate attached as described
above. The massive cast iron retort has proved more satisfactory.
GENERAL OPERATIONS 35
Connect the delivery tube from the retort with a 750 cc. Er-
s+
1=1
n
ftll
-LJL
Fig. I7A. Single tube retort, heated by gas, for the distillation of wood or calcium
acetate. The whole apparatus is enclosed in a case of asbestos board to con-
serve the heat. The cover with the asbestos washer (A) is held in place
by two dogs and wedges (D). The volatile products pass out from
the retort through tube (T) to the condenser.
lenmeyer flask and the latter with a condenser and settling bottle
(2 l / 2 liters) as shown in Fig. 18. The exit from the settling
CLn apparatus for collecting J}&s t ilia 1 6 from
Fig. 18.
bottle is connected with a burner where the combustible gases
are burned as they escape. When all is ready heat the retort
30 ORGANIC CHEMISTRY
moderately so that toward the end of the distillation the ther-
mometer goes to 2io-22O. Under these conditions the dis-
tillation will require about 5 hours and the products will be
about 40 per cent charcoal, 40 per cent, distillate, and 20 per
cent. gas. If the heating is more rapid, so that the distillation
is completed in three hours and the temperature reaches 300,
the charcoal will be only about 30 per cent., the distillate 45
per cent, and the gas 25 per cent. In the latter case the amount
of tar will also be increased and the products obtained are likely
to be more impure.
When the distillation is completed separate the
aqueous portion from the tar and distil the for-
mer from 1 a flask connected with a Hempel col-
umn of glass beads (Fig. i8A). The tar is also
heated to 140 in an oil-bath and any distillate
obtained is mixed with the aqueous portion
and distilled with that. Any oil which separates
from the distillate is separated by means of a
separatory funnel (p. 127). Repeat the distilla-
tion a second time to secure as complete a separa-
tion from the tar as possible. Unite the aqueous
distillates in an Erlenmeyer flask and neutralize
them with a thick paste of calcium hydroxide
added in small portions, cooling after each addi-
tion and determining the end of the neutraliza-
tion by means of litmus paper. Filter on a
moistened filter from some tar which separates
and from impurities of the lime which remain.
Distil the filtrate, adding some pieces of porous
porcelain to prevent bumping and collecting the
distillate in three of four fractions, stopping the
distillation when the temperature reaches 100.
Fractionate the distillate systematically to sepa-
rate the methyl alcohol and acetone. The crude
Fig. ISA. methyl alcohol may be freed from acetone
by means of sodium hydrogen sulphite. The acetone may also
GENERAI, OPERATIONS 37
be converted into the double compound with acid sodium sul-
phite (p. 92).
Evaporate the residue from which the methyl alcohol and
acetone have been distilled and obtain from it ordinary gray
calcium acetate.
Chapter III
HYDROCARBONS
Hydrocarbons may be prepared by distilling salts of acids
with soda-lime or barium hydroxide, or in some cases, with sod-
ium methylate (Mai: Ber., 22, 2133.)
RCO 2 Na + NaOH = RH + Na 2 CO 3 .
A second method consists in treating halogen derivatives ot
the hydrocarbons with sodium, usually in ethereal solution, or
with zinc alkyl compounds.
RI 4- R'i _j_ 2 Na = R R' -j- 2 NaI.
-D/
2RI + Zn/ = 2R R' -f ZnL.
>&'
These methods are of especial value for the determination of
structure.
A somewhat related method consists in treating a mixture of
an aromatic hydrocarbon and an alkyl chloride, bromide, or
iodide with dry aluminium chloride (Friedel and Crafts). This
method of synthesis loses very much in value from the fact that
side chains of aromatic hydrocarbons may be removed by the
action of aluminium chloride, and rearrangements are liable to
result. As an illustration of the reaction, the synthesis of tri-
phenyl methane may be given.
C 6 H 5X
3 C 6 H 6 -f CHC1 3 + Aid, = C 6 H 5 CH -f 3 HC1 -f Aid..
C H '
^6^5
The reaction appears to give at first a compound of aluminium
chloride with the hydrocarbon, C 6 H 5 A1C1 2 , and this compound
then reacts with the chloroform forming triphenylmethane and
regenerating the aluminium chloride.
Alcohols are usually converted into unsaturated hydrocarbons
when treated with concentrated sulphuric acid, (see 7, p. 44)
HYDROCARBONS 39
or zinc chloride, or they may be converted indirectly, by the
preparation from them of a halogen alkyl, and treatment of the
latter with alcoholic potash.
/OH /HSO,
R"< + H 2 S0 4 = R"< + H 2 0.
\H X H
A
R<
\H
- R" + H 2 SO,.
KOH = R" -t- KI H- H 2 O.
In some cases quinoline may be used with advantage in place
of alcoholic potash. (Baeyer: Ber., 25, 1840, 2122.)
Monohalogen derivatives of hydrocarbons may be reduced to
the hydrocarbon, the reducing agents most commonly used being
cencentrated hydriodic acid; the copper zinc couple in the pres-
ence of alcohol or water (Gladstone and Tribe: Ber., 6, 202,
454, 1136; J. Chem. Soc., 1884, 154); zinc in water at 150-
160 (Frankland: Ann., 71, 203; 74, 41); and aluminum chlo-
ride at i2O-i5o (Kohnlein: Ber., 16, 560; Kluge: Ann., 282,
214.) The author has found that Kohnlein's method gives a
mixture of compounds when applied to isobutyl iodide. The
iodides are more suitable than other halogen derivatives for these
reactions.
RI + HI = RH + I 2 .
/R
2 RI -f- 2 Zn = Zn< -f- Znl.,.
/
= Zn<
\R
Zn< -f 2H t ) Zn(OH) 2 + ?RH.
Compounds having two halogea atoms combined with adjacent
carbon atoms,, lose both bromine atoms with the formation of an
unsaturated hydrocarbon on treatment with sodium, or with
zinc dust and acetic acid, or with mercuric iodide, or lead iodide.
Under the influence of condensing agents, such as concen-
trated sulphuric acid, zinc chloride, and phosphorus pentoxide,
4O ORGANIC CHEMISTRY
or pentasulphide, ketones, aldehydes, and sometimes other com-
pounds, frequently condense to form hydrocarbons. In this way
mesitylene is formed from acetone, and cymene from the open
chain aldehyde, geranial. (Semmler: Ber., 23, 2965; 24, 205.)
The formation of cymene from camphor is analogous in some re-
spects, but involves a separation of two carbon atoms instead
of a condensation.
A great variety of hydrocarbons, especially methane, olefmes,
acetylene, and aromatic hydrocarbons, are formed by heating or-
ganic compounds to high temperatures.
Aromatic hydrocarbons may be reduced to "alicyclic" com-
pounds by reduction with hydriodic acid at high temperatures,
or, sometimes, by means of amyl alcohol and sodium. Zelinsky
has shown, however, that hydriodic acid at high temperatures
transforms cyclohexane into methyl cyclopentane. (Ber., 30,
387.)
G 6 H 6 + 6HI = C 5 H 9 CH 3 + 3 I 2 .
Ci H 8 + 4^ = C 6 H 4 .C 4 H 8 .
Naphthalene. Naphthalene
tetrahydride
Benzene may be reduced to cyclohexane and many other com-
pounds may take up hydrogen when heated to a moderate tem-
perature with hydrogen in the presence of finely divided nickel.
(Sabatier and Senderens, see n, p. 50.) Somewhat similar re-
ductions may be effected at ordinary temperatures by hydrogen
in the presence of colloidal palladium or finely divided platinum.
(Ber.; 41, 1475.) Little has been said about the theory of these
reactions but it would seem that the hydrogen gas is separated
into hydrogen atoms or ions under the influence of the metal.
Ketones, phenols, alcohols, and in some cases acids, may be
reduced to hydrocarbons by heating with concentrated hydriodic
acid, or hydriodic acid and phosphorus, usually in sealed tubes.
:>
CQ + 4 HI = >CH 2 + 2l, + H 2 0.
R/
Phenols, and sometimes other oxygen compounds, may be
HYDROCARBONS 4-1
duced to hydrocarbons by distilling over heated zinc dust, usually
in a hard glass tube in a combustion furnace.
The carbides of the metals, when treated with water, or with
acids, give hydrocarbons which differ with the metal. Calcium
carbide gives acetylene, aluminium carbide gives methane, iron
carbide chiefly olefines. (Moissan: Compt. rend., 122, 1462.)
Aromatic amines may be converted into hydrocarbons by
treatment with nitrous acid and alcohol (see 100, p. 212). Some-
times, however, the reaction causes the replacement of the amine
group by the ethoxy group, C 2 H 5 O, instead of hydrogen. ( Ren>
sen and his co-workers: Am. Chem. J., 8, 243; 9, 387; n, 319;
15, 105; IQ, 163; 20, 229.)
5. Preparation of a Hydrocarbon by Distilling the Salt of an
Acid with Soda-Lime. Methane, CH 4 .
Literature Preparation from sodium acetate and barium oxide, Dumas:
Ann., 33, 81 ; Ladenburg u. Kriigel : Ber., 3 2 1820 ; From methvl iodide,
Gladstone and Tribe: J. Chem. Soc., 43, 154; From aluminium carbide,
Moissan: Bull. soc. chim., n f 1012; 15, 1285; Formation from the ele-
ments, Bone and Jerdan : J. Chem. Soc., 7 1 * 42.
10 grams anhydrous sodium acetate.
10 grams soda-lime.
Grind together and mix intimately in a mortar 10 grams of
fused sodium acetate and 10 grams of soda-lime. Put the mixture
in a 100 cc. hard glass retort or in a 20 cm. hard glass test-tube.
Support the retort or tube with a clamp attached to a retort
stand. Connect by means of a delivery tube of india-rubber or
glass with bottles and other receptacles filled with water and in-
verted in a pan or dish. Heat the contents of the retort or tube
strongly with a Bunsen burner and collect the gas evolved, al-
lowing the first portions, which contain air, to escape. Per-
form the following experiments with the gas.
1. Pour the gas upward from one bottle to another. What
is the weight of the gram molecular volume of the gas and how
does the weight compare with the weight of air?
2. Mix with the amount of air required for complete com-
42 ORGANIC CHEMISTRY
bustion (assuming that air contains % of its volume of oxygen)
in a 300 cc., wide mouthed, strong bottle and explode the mix-
ture.
3. Fill a test-tube with the gas, introduce I cc. of bromine water,
stopper the tube and expose to direct sunlight, or for a longer
time to diffused daylight.
4. Examine the residue of the materials from which the gas
was generated for carbonate.
How many grams of sodium acetate would be required to
generate one gram molecular volume of methane? How many
liters should 10 grams of the acetate give?
The preparation of benzene, p. 50, is the same in principle as
that of methane given here. The method may also be applied
to salts of sulphonic acids.
6. Preparation of a Hydrocarbon from a Halogen Compound
by Reduction. Ethane, C 2 H 6 . Determination of the density.
Literature Identity of ethane from electrolysis of acetic acid and
from reduction of ethyl iodide, Schorlemmer: Ann., is 1 , 76; i3 2 > 234;
Presence in natural gas, L. Smith: Ann. chim. phys., 8, 566; Preparation
from ethyl iodide, Gladstone and Tribe: Ber., 6, 202; J. Chem. Soc., 45>
154; Properties Ladenburg and Kritgel : Ber., 3 2 , 1821; Olzewsky: Ber,
2 7 3306 ; Hainlen : Ann., 282, 245.
5 grams powdered zinc.
2 per cent, solution of copper sulphate.
10 grams ethyl iodide.
5 cc. alcohol.
Prepare a round bulb, as shown in Fig. 19, sealed to a
three-way stop-cock and having a capacity of 100 to 125 cc.
Determine the capacity of the bulb by weighing it empty and
filled with water at 20 exactly to the stop-cock, using the di-
rections for calculation given on p. 33. Remove the water and
dry the bulb thoroughly by warming and exhausting it re-
peatedly with a good filter-pump. Finally, when cold, exhaust
the bulb while connected with a manometer, measuring the pres-
sure of the residual air and the temperature. Place in the bal-
ance case and weigh, noting the temperature of the balance case.
HYDROCARBONS
43
Put 5 grams of powdered zinc (30 mesh, such as is used in the
Jones reductor) in a 20 cm., heavy walled test-tube, add 5 cc. of
a 2 per cent, solution of copper sulphate and shake till the solu-
tion becomes colorless. Pour off the solution of zinc sulphate,
add more of the copper sulphate and repeat a third and fourth
time. Finally wash repeatedly by decantation and once with
alcohol. Cover the zinc with 5 cc. of alcohol, close the tube
with a stopper having two holes through one of which passes a
thistle tube dipping below the surface of the alcohol and through
the other a delivery tube connected with two potash bulbs, the
Fig. 19.
first containing alcohol and the second concentrated sulphuric
acid. The alcohol is to absorb vapors of ethyl iodide which
might escape and the sulphuric acid to remove vapors of alcohol
and water. Connect the second bulbs with the exhausted and
weighed bulb mentioned above, the stop-cock being placed in
such a manner that the first gas will escape through the side
tube. To the latter is attached a delivery tube conveying the gas
to an inverted bottle for collecting the gas over water. From
the generator to the weighed bulb all connections should be made
by bringing the glass tubes together within short, tightly fitting
pieces of rubber tubing.
When everything is ready, prepare a mixture of 10 grams of
ethyl iodide, 5 cc. of alcohol and one or two drops of dilute
44 p RGANIC CHEMISTRY
sulphuric acid. Add this mixture to the generator through the
thistle tube, warming very gently at first, if necessary, to start
the reaction but cooling later, if the reaction becomes rapid.
The mixture must be added carefully, in such a manner that
bubbles of air are not carried down the thistle tube. Allow about
300 cc. of gas to collect in the bottle to insure the removal
of the air in the apparatus, then turn the stop-cock very cau-
tiously so that the gas will enter the exhausted bulb. The
column of liquid in the thistle tube must be carefully watched
and the gas must not pass into the bulb so fast that air- is
drawn down through it into the generator. When no more gas
will enter the bulb with the stop-cock wide open, the stop-cock
is closed and the bulb disconnected. The stop-cock is then opened,
momentarily, to allow the gas within to come to atmospheric
pressure, care being taken that the bulb is not warmed by the
hand. The temperature and barometric pressure are then noted
fcnd the bulb weighed. From the results calculate the weights
of a liter and of a gram molecular volume (22.4 liters) of the
gas.
The method described, with slight modifications, may be used
to replace iodine by hydrogen in almost any aliphatic compound
or in aromatic compounds containing iodine in the side chain,
sometimes, also, when the iodine is in the nucleus. Since al-
coholic hydroxyl in alcohols^ hydroxy acids and other compounds
may usually be replaced by iodine on treatment with concen-
trated hydriodic acid the method may often be used for the
indirect replacement of hydroxyl by hydrogen.
7. Preparation of a Hydrocarbon of the Ethylene Series.
CH 2 Br
Ethylene dibromide, | (dibrom (1.2) ethane).
CH 2 Br
Literature Balard: Ann chim. phys. [2], 32, 375 (1826); Erlenmeyer
and Bunte: Ann., 168, 64; 192, 244; Denzel : Ibid, 195, 210; Thorpe: J.
Chem. Soc., 37, 1/7 (1880); Anschiitz: Ann., 221, 137; V. Meyer u.
Miiller: Ber., 24, 4249; Tawildarow: Ann., 176, 12; Use of phosphoric
acid, Newth: J. Chem. Soc., 79, 915; Theory for the formation of ether
and ethylene, Nef : Ann., 309, 141 ; 318, 50.
HYDROCARBONS 45
30 cc. alcohol.
50 cc. sulphuric acid (1.84).
50 cc. alcohol.
50 cc. sulphuric acid.
20 cc. (60 grams) bromine.
Put 30 cc. of alcohol in a liter flask. Add 50 cc. concentrated
sulphuric acid. Arrange a flask as shown in Fig. 20 with a
thistle tube bearing a stopper with a separatory funnel having
a short stem. By this arrangement the rate at which the con-
tents of the funnel is dropped into the mixture can be seen and
regulated. The lower end of the thistle tube should be drawn out
to a diameter of about 2 mm. for about 10 cm. and then bent back
twice on itself as shown in Fig. 20. If this is properly done the
tube will still pass through the hole of a rubber stopper, and a uni-
form, slow delivery from the end of the tube can be secured. Con-
nect with a wash-bottle containing caustic soda, and with a second
wash-bottle containing concentrated sulphuric acid and having
a safety-tube, then with a thick walled tube about 15 mm. in
diameter, fitted with tubes like a wash-bottle and containing
20 cc. of bromine covered with a little water. The latter should
be placed in cold water and connected with a tube opening just
above the surface of a sodium hydroxide solution in a large
bottle. Place the generating flask on a thin asbestos paper,
and heat till the thermometer (not shown in the figure) in
the mixture reaches I7O-I75. It is an advantage to heat mo-
mentarily to i85-i9O and then allow the mixture to fall back
to the temperature specified. When the evolution of ethylene
has well begun, drop in slowly a mixture of 50 cc. of alcohol
with 50 cc. of concentrated sulphuric acid, keeping the tempera-
ture at about 170. Continue the passage of the gas till the
bromine becomes nearly colorless. The mixture in the generat-
ing flask should not carbonize. If it should do so, from too rapid
heating, it is usually best to empty the flask and put in a new
mixture of alcohol and acid. Transfer the ethylene bromide to
a separatory funnel, add some water and agitate gently, separate,
add a dilute solution of sodium hydroxide to alkaline reaction,
46 ORGANIC CHEMISTRY
shaking gently with care not to form an emulsion and draw off
Hg. 20.
into a dry flask. Drops of the ethylene bromide often remain
floating on top of the liquid. These can sometimes be caused
HYDROCARBONS
47
to settle by gentle agitation but it is usually best to fill the sep-
aratory funnel nearly full with water to lessen the area of the
upper surface and make it easier to shake down the heavier liq-
uid. Add some fus.ed calcium chloride and allow tcjystand for
NfiOH
sometime to dry the liquid. Filter into a dry distilling bulb,
and distil. The yield is nearly equal to the weight of the bro-
mine used.
Ethylene bronrde solidifies at a low temperature and melts at
9.5. It boils at 130.3, and has a specific gravity of 2.1785 at
20. When warmed in alcoholic solution with granulated zinc,
ethylene is regenerated. With alcoholic potash vinyl bromide
and acetylene are formed. Other compounds having two halogen
atoms combined with adjacent carbon atoms react in a similar
manner.
8. Preparation of a Hydrocarbon from a Carbide. Acetylene,
CH = CH.
Literature. Preparation of carbides, Moissan : Bull. soc. chim. (3),
n 1002, 1010; Preparation of hydrocarbons from carbides, Wohler: Ann.,
124, 220; Moissan: Bull. soc. chim., n, 1012; i5 1285; Ber., 4 5120;
W. E. Gibbs: Acetylene Gas, its Production and Use; London, 1898;
Composition of copper and silver acetylides, Keiser: Am. Chem. J., 14*
285; Soderbaum: Ber., 30, 760; Explosion of acetylene as an endothermic
compound, Berthelot, Vielle : Compt. rend., i23 523 ; Ann. chim. phys., (7,)
48 ORGANIC CHEMISTRY
XI 55 Comparative safety of acetylene in acetone, Claude, Hess: Compt.
rend., 124, 626; Berthelot, Vieille: Compt. rend., 124, 988, 996, 1000. See
also the following preparation.
10 grams of calcium carbide.
Water.
1 gram cuprous chloride.
5 cc, ammonium hydroxide (10 per cent. NH 3 .)
20 cc. water.
0.2 gram silver nitrate.
2 cc. ammonium hydroxide.
10 cc. of water.
Put 10 grams of calcium carbide in a 200 cc. flask. Fit the
flask with a stopper bearing a separatory funnel and a delivery
tube. From the separatory funnel drop water slowly upon the
carbide and conduct the gas through a solution of one gram
of cuprous chloride dissolved in dilute ammonium hydroxide,
also through a solution of 0.2 gram of silver nitrate (2 cc. of a
10 per cent, solution) dissolved in dilute ammonium hydroxide.
Filter off the precipitates, transfer them to dry filter-paper and
allow to dry in the air. Explode portions of the precipitate by
heating over the flame on a piece of tin foil or sheet iron, using
very small amounts for the first trials. Destroy all of the pre-
cipitates by explosion or treating with dilute acids before leaving
the laboratory.
If an acetylene burner is available, the illuminating quality of
the gas may be tested after all of the air has been expelled
from the generator. This may be determined by collecting some
of the gas in a test-tube and seeing whether it explodes on the
application of a flame.
Acetylene is better generated on a larger scale by dropping
the carbide into water and this plan is adopted in the better
forms of generators. Why? How many liters of acetylene
should 10 grams of calcium carbide yield?
.Acetylene tetrabromide may be prepared by passing acetylene
HYDROCARBONS 49
into bromine as described on p. 45 for preparing ethylene bromide.
It must be distilled under diminished pressure, however.
9. Preparation of a Hydrocarbon by Decomposition of a Halo-
gen Compound with Sodium Ethylate. Acetylene, CH = CH.
Literature. Formation by incomplete combustion of illuminating gas,
Rieth: Z. f. Chemie, 1867, 599; By direct union of carbon and hydrogen,
Berthelot: Ann. chim phys., (4), 13* 143; From vinyl bromide or ethylene
bromide and alcoholic potash, Sawitsch: J., 1861, 646; Sabanejew: Ann.,
i7 8 in ; By passing ethylene chloride over heated soda-lime, Wilde: Ber.,
7 35 2 ; By reduction of tetrachlorethane with zinc, Sabanejew: Ann., 216,
262 ; By electrolysis of f umaric or maleic acid, Kekule : Ann., is 1 ! 85 ; See
also the preceding preparation.
5 grams sodium.
60 cc. absolute alcohol.
10 grams ethylene bromide.
Connect a 200 cc. flask with an upright condenser making
sure that the connection is gas tight. A rubber stopper may be
used. Put in the flask 5 grams of clean metallic sodium from
which the outer crust has been cut with a knife. The shavings
of sodium must be put in the bottle kept for the purpose. It is
dangerous to throw them into a slop jar or a sink. Pour through
the condenser, in portions, 60 cc. of absolute alcohol. This may
be all added within 5 to 10 minutes but the reaction should not
be allowed to become violent. After the alcohol has all been added,
boil gently on a wire gauze covered with asbestos till the sodium
is all dissolved. Allow to cool, connect the top of the condenser
with a small U-tube containing alcohol (to absorb some vinyl
bromide, which will escape) and from that to a U-tube or small
flask containing a solution of I gram of cuprous chloride in 25
cc. of dilute ammonium hydroxide or 0.2 gram silver nitrate in
the same solvent. Pour TO grams of ethylene bromide through
the condenser into the cooled solution of sodium ethylate and
warm gently to cause a slow evolution of acetylene. Perform
the experiments with the copper acetylide and silver acetylide
which are described in the preceding preparation.
From the alcohol in the U-tube a small amount of vinyl bromide
may be precipitated by adding crushed ice and water. The
4
50 ORGANIC CHEMISTRY
vinyl bromide boils at 16 and, of course, becomes a gas at ordi-
nary temperatures.
The action of the sodium ethylate in this preparation is simi-
lar to the action of alcoholic potash upon almost any aliphatic
halogen compound in which the grouping >CH CBr (Cl, I)<
occurs, the halogen being removed along with a hydrogen atom
which is attached to the carbon atom adjacent to the one bearing
the halogen.
Metallic compounds analogous to the copper acetylide (more
properly called copper carbide) are formed from all derivatives
of acetylene having the grouping C = CH but not from com-
pounds of the type R C = C R.
10. Preparation of a Hydrocarbon by Distillation of a Salt of
an Acid with Soda-Lime. Benzene, C 6 H 6 . (Phen.)
Literature Mitscherlich : Ann., 9> 39; Marignac: Ibid, 4 2 217; Wohler :
Ibid, 51, 146; Berthelot: Ann. chim. phys. [4], 9> 469; Hofmann : Ber., 4,
163; Baeyer: Ibid, 12. 1311; V. Meyer: Ibid, 16, 1465.
20 grams benzoic acid.
40 grams soda-lime. ,.
Mix 20 grams of benzoic acid with 40 grams of soda-lime
by grinding together in a mortar. Put the mixture in a small
flask, connect with a condenser, and distil over the free flame.
Separate the benzene from the water, dry it with calcium chlo-
ride, and distil. If perfectly, dry benzene is desired, distil it a
second time over metallic sodium. Yield 8 to 9 grams.
Benzene solidifies at a low temperature, and melts at 5.40.
It boils at 80.12.
This method of preparation is no longer practically used, but
it was of very great importance in the early study of the aro-
- matic hydrocarbons, and illustrates a method very general in its
application.
11. Reduction of a Hydrocarbon by Hydrogen in the Presence
of Finely Divided Nickel. Sabatier's Method. Cyclohexane,
CH 2 CH 2 CH.,
I I "-
CH, CH. CH 2
HYDROCARBONS 5 I
Literature Application of the method to a great variety of substances,
Sabatier and Senderens : Ann. chim. phys. (8), 4, 319-488; Compt. rend.,
132, 210, 566; Chem. Centrbl., '01, I, 501, 817; '05, I, 1004, 1317; Reduction
of phenol to cyclohexanol, Sabatier and Senderens: Compt. rend., i37
1025 ; Structure of the hydrocarbon formed by reduction of benzene by
hydriodic acid, Kijner: J. prakt. Chem. (2), 56, 364; Description of pro-
cess, Henle: Anleitung fur das organisch praparative Praktikum, p. 79.
Preparation of Finely Divided Nickel
Break some porous porcelain plates into pieces 3 to 5 mm.
in diameter and separate them from the dust by means of a sieve.
Pour over them in a flat dish a concentrated solution of nickel
nitrate and evaporate on the water-bath to dryness, with f recfuent
stirring. When dry, transfer to a nickel crucible and heat over
the free flame till no more oxides of nitrogen are evolved. Fill
a tube of hard glass, about one meter long and 2 cm. in diameter
with the pieces, putting some pieces of broken marble at each
end to hold them in place. Draw out one end of the tube and
bend it downward or correct with an adapter as shown in Fig. 22.
Place the tube in a combustion furnace inclined at an angle
so that the water formed by reduction of the nickel oxide -will
run away at the lower end, and heat at about 500 (measured
with a thermometer filled with nitrogen or carbon dioxide above
the mercury) in a rapid current of pure hydrogen for several
hours until water no longer condenses in the delivery tube con-
nected with the lower end. The end of the delivery tube should
dip under concentrated sulphuric acid to prevent diffusion of air,
as only nickel, which has been freshly reduced at not too high
a temperature and afterwards portected from the air, is effective.
Cool in a slow current of hydrogen.
Arrange the apparatus shown in the figure so that the hydrogen
from the Kipp generator passes first through a concentrated
solution of potassium permanganate, then through concentrated
sulphuric acid, then through a distilling bulb containing 50
grams of benzene. The latter is placed in a beaker of water
which can be warmed. Before warming, however, and before
connecting the apparatus with the tube containing the reduced
nickel the hydrogen is allowed to pass long enough to expel air
ORGANIC CHEMISTRY
HYDROCARBONS 53
from the apparatus. The tube containing the nickel is placed
in a Volhard ' bath (Ann., 284, 235) filled with high boiling
gasoline or kerosene which is set to maintain a temperature
of 195 by distilling away the low boiling portion till that
temperature is reached in the bath. When the air has been
expelled, connect the delivery tube of the distilling bulb con-
taining the benzene with the- tube containing the nickel and con-
nect the lower end of the latter to a tube reaching just below
the neck in a 200 cc. distilling bulb surrounded with ice water.
The side tube of this bulb is connected to a tube dipping into
25 cc. of alcohol contained in a second distilling bulb, which. is
also surrounded with ice water. The alcohol is to retain vapors
of cyclohexane which escape condensation in the first bulb.
Maintain the temperature of the bath containing the tube with
the nickel at 195, that of .the water in the beaker surrounding
the benzene at 35. At the latter temperature the vapor pressure
of benzene is about 145 mm. If the hydrogen is saturated with
benzene vapor at that vapor pressure, what per cent, excess of
hydrogen will be used? The hydrogen may pass at such a rate
that the bubbles may be easily counted. After six or eight
hours 30 to 40 grams of cyclohexane should have collected in
the bulb surrounded with ice-water. A few grams additional
may be obtained by diluting the alcohol contained in the second
bulb. The precipitated hydrocarbon is mixed with the rest and
the whole shaken, by means of a shaking machine, with an equal
volume of fuming sulphuric acid containing 10 to 14 per cent,
of sulphur trioxide. This will convert unchanged benzene into
benzene sulphonie acid which dissolves easily in water. Pour
carefully into 4 or 5 volumes of cold water, cooling after each
addition. Separate cyclohexane by means of a separatory fun-
nel, dry with calcium chloride and distil. Yield 70 to 80 per
cent, of the weight of benzene used.
Cyclohexane boils at 81 and freezes at a low temperature,
melting at 4.7.
Test the cyclohexane for benzene by warming on the water-
bath in a test-tube a few drops with a mixture of 3 cc. of con-
54 ORGANIC CHEMISTRY
centrated sulphuric acid and 3 cc. of nitric acid (sp. gr. 1.42).
Dilute with water, add a little ether, shake, allow the ether to
rise to the top and transfer it to a dry test-tube by means of a
pipette with a rubber tube attached. (Fig. 23). Evaporate the
ether, by dipping the tube in a water-bath, add i cc. of concen-
trated hydrochloric acid and a piece of tin. After warming
a short time, dilute slightly, add a solution of sodium hydroxide
in excess, extract with ether as before, and evaporate in a dry
test-tube. Test the residue for aniline by dissolving in water
Fig. 23.
and adding a filtered solution of chloride of lime. . Try the same
test with a drop of pure benzene.
The method of reduction discovered by Sabatier may be ap-
plied to a great variety of substances, and has made some sub-
stances which were formerly very difficult to obtain comparatively
easily accessible.
12. Preparation of Hydrocarbons by Means of Halogen
Compounds and Sodium. Fittig's Synthesis. Paraxylene.
/CH 3 (i).
C 6 H/ ( i .4-Dimethylphen. )
X CH 3 ( 4 ).
Literature. Synthesis from />-bromotoluene, Fittig, Glinzer : Ann.,
I 36, 303; Jannasch: Ibid, i? 1 * 79; Ber., 10, 1356; From dibromo-
benzene: V. Meyer: Ber., 3> 753; Preparation from coal tar through
HYDROCARBONS 55
the sulphonic acid; Jacobsen : Ibid, 10, 1009, 1356; Crafts: Z. anal.
Chem., 32, 243; Compt. rend., 114* mo.
35 grams parabromotoluene.
35 grams methyl iodide.
12 grams sodium wire.
loo cc. ether.
Press into a 200 cc. flask 12 grams of sodium in the form
of wire, add 100 cc. of dry ether (see 76, p. 175), place the
flask in ice-water, connect with an upright condenser, and add
through the latter a mixture of 35 grams of parabromotoluene,
and 35 grams of methyl iodide. Allow the mixture to stand
over night, or till the reaction appears to be complete. Distil
off the ether on the water-bath, and distil the hydrocarbons
formed over the free flame. Remove the remainder of the ether
from the oil, by allowing it to stand in a crystallizing dish for
half an hour in vacua over sulphuric acid. Fraction repeatedly
from a small distilling bulb, using test-tubes to collect the dis-
tillates, and avoiding loss, as far as possible. Collect as much as
possible of the paraxylene, within an interval of 2 to 3 degrees.
Cool this portion with ice, or in a freezing mixture, and pour
off the part which does not solidify. Yield 5 to 7 grams.
The residue in the flask will contain free sodium and should
be treated with alcohol to destroy this and then with water. It
must never be allowed to stand or be thrown into a slop jar with-
out this.
Paraxylene melts at 15, boils at 138, and has a specific gravity
of 0.880 at o. It is oxidized by dilute nitric acid to paratoluic
acid, and by the chromic acid mixture to terephthalic acid.
This synthesis by means of halogen compounds and sodium,
known as the Fittig synthesis, has been very useful in de-
termining the structure of halogen derivatives and of hydrocar-
bons.
In some cases when the reaction takes place slowly or not at
all it may be catalyzed by means of a little dry ethyl acetate.
56 ORGANIC CHEMISTRY
13. Preparation of a Hydrocarbon from Camphor. Cymene,
/CH 3 (i)
yCH<
C 6 H/ X CH 3 (p Methyl-isopropylphen.)
X CH 3 (4)
Literature Occurrence, Gerhardt and Cahours: Ann., 38, 71, 101, 345;
Preparation from camphor, Gerhardt : Ibid, 4 8 > 234 ; Dumas, Delaland : Ibid,
38, 342; by Fittig's synthesis, Sylva : Bull. soc. chim.,43 321; Jacobsen:
Ber., 12, 430; Widman: Ibid, 24, 450; From turpentine, Kekule: Ibid, 6,
437; Detection in terpenes, Hartley: J. Chem. Soc., 37 676; Molecular
rearrangements in the formation of cymene, Noyes: J. Am. Chem. Soc.,
3i, 13/2.
30 grams camphor.
30 grams phosphorus pentoxide.
Mix intimately in a flask 30 grams of camphor, and 30 grams
of phosphorus pentoxide. Connect with a condenser, and heat
in an oil-bath as long as cymene distils. Add to the cymene a
little phosphorus pentoxide, and boil a short time with an upright
condenser. Pour off, and repeat a second ti-ne. Then boil the
cymene with some sodium for a short time, using an upright
condenser, and finally distil. Yield 15 to 17 grams.
Cymene boils at 175, and has a specific gravity of 0.8525 at
25. Potassium permanganate oxidizes it to hydroxypropylben-
/CH,
/COH/
zoic acid, C 6 H 4 <^ CH 3 ; the chromic acid mixture to tere-
X C0 2 H
phthalic acid; dilute nitric acid to par?toluic acid.
14. Determination of a Hydrocarbon by a Pyrogenic Reaction.
Diphenyl, C 6 H 5 C 6 H, 5 .
Literature Preparation by Fittig's syntheses, Fittig: Ann., 121, 363;
From benzene at a high temperature, Berthelot: Z. anal. Chem., 1866,
707 ; La Coste, Sorger : Ann., 230, 5 ; From phthalic anhydride and lime,
Anschiitz, Schultz : Ann., 196, 48; From benzene and tin tetrachloride at
a high temperature, Aronheim: Ber., 9, 1898; Smith: Ibid, 12, 722; Z.
Elektrochemie, 7 903.
200 cc. benzene.
Fill the central portion of an iron tube, 2 cm. in diameter, and
HYDROCARBONS 57
about 50 cm. longer than the combustion furnace, with broken
pumice. Connect with one end of the tube, by means of a per-
forated cork, a tube 15 mm. in diameter, which is drawn out
at one end and bent at right angles. Into the wider portion of
the tube, which is bent upward, fit a cork bearing a separatory
funnel in such a way that the benzene can be seen as it drops
from the end of the funnel. Raise this end of the combustion
furnace about two inches higher than the other. Connect the
other end of the iron tube with a small condenser, by means of
a cork and glass tube. Drop benzene from the separatory funnel
at the rate of about 15 drops per minute, heating the central por-
tion of the tube to dull redness. When 200 cc. of benzene have
been dropped into the tube in this manner, distil the distillate,
and return to the separatory funnel the part boiling below 120.
Repeat till a considerable quantity of high boiling products has
been obtained. The benzene condenses with evolution of hy-
drogen.
2 C 6 H 6 = C 6 H 5 .C 6 H 5 + 2 H.
Fractionate the product and crystallize from alcohol the por-
tion boiling from 235-3OO.
Diphenyl crystallizes in leaflets, which melt at 70. It boils at
254, and dissolves in 10 parts of alcohol at 20.
15. Preparation of a Hydrocarbon by the Reduction of a Ke-
tone with Hydriodic Acid. Diphenylmethane, C 6 H 5 CH,2C 6 H 5 .
Literature Preparation by reducing benzophenone with hydriodic
acid and phosphorus, Graebe: Ber., 7> 1624; With zinc and sulphuric acid,
Zincke, Thorner : Ber., .10, 1473 ; With zinc dust, Staedel : Ann., iQ4, 307 ;
From benzyl chloride and benzene with zinc dust, Zincke: Ibid, i59 374;
By Friedel and Crafts reaction, Friedel, Crafts: Ann. chim. phys. [6],
i, 478; E. and O. Fischer: Ann., iQ4i 253; By condensing methylal with
benzene, Baeyer: Ber., 6, 221.
10 grams benzophenone.
12 grams hydriodic acid (boiling-point 127).
2.2 grams red phosphorus.
Put in a tube 15 mm. in diameter, and with walls 2 mm. thick,
10 grams of benzophenone, 12 grams of hydriodic acid (boiling-
58 ORGANIC CHEMISTRY
point 127), and 2.2 grams of red phosphorus. Seal caretully
(see p. 20), and heat for 6 hours at 160 in a bomb oven.
Open the tube carefully by softening the capillary end in a flame
till it blows out. Cut off the end of the tube, add some water
and ether to dissolve the hydrocarbon. Separate the ethereal so-
lution, filter it from the red phosphorus, distil off the ether, and
distil the diphenylmethane from a small distilling bulb. Yield
8 to 8.5 grams.
Diphenylmethane melts at 26 -27, and boils at 263. It is
easily soluble in alcohol and ether. It has a specific gravity of
26
1.0008 at o .
4
Reduction by means of hydriodic acid has been very often
used to replace hydroxyl or oxygen with hydrogen in determin-
ing the structure of compounds.
1 6. Synthesis of a Hydrocarbon by Use of Aluminium Chloride.
C 6 H 5X
(Friedel and Crafts' Reaction.) Triphenylmethane, C 6 H 5 CH.
OH/
M> n 5
Literature Preparation from benzylidene chloride and mercury phenyl,
Kekule, Franchimont: Ber., 5> 907; By Friedel and Crafts, reaction,
Friedel, Crafts: Ann chim, phys., [6], i, 489; Compt. rend., 84, 1450;
Anschutz: Ann., 235, 208, 337; E. & O. Fischer: Ibid, iQ4 352; Allen,
Kollicker : Ibid, 227, 107 ; Biltz : Ber., 26, 1961 ; Linebarger : Am. Chem.
J> X 3> 557 > Study of conditions for the reaction, Norris and McLeod :
Am. Chem. J., 26, 499 ; Solubility of triphenylmethane in benzene, Line-
barger : Am. Chem. J., i5 46.
200 grams of benzene.
40 grams chloroform.
20 grams aluminium chloride.
Mix 200 grams of benzene with 40 grams of chloroform, add
some fused calcium chloride, and allow the mixture to stand
over night. Pour off, or filter, into a dry flask, connect the lat-
ter with an upright condenser having a calcium chloride tube,
which is bent downward, connected with its top. Weigh in a
stoppered preparation tube 20 grams of aluminium chloride, best
HYDROCARBONS 59
freshly prepared. 1 Add from the tube to the mixture of chloro-
form and benzene 3 to 4 grams of the aluminium chloride. Shake
and warm until the reaction begins; after five to ten minutes
add a second portion of the chloride, and add all of it in this
manner in about thirty minutes. Boil the mixture gently for
an hour, cool, pour carefully into 200 cc. of water, stir, transfer
to a separatory funnel, shake, and separate the oil from the water,
filter through a filter moistened with benzene to remove water,
distil off the benzene, and collect in fractions, below 100, ioo-
200, 200-300. Transfer the residue to a smaller distilling
bulb or retort, and distil without a thermometer, or with a
thermometer filled with nitrogen under pressure, till the distillate
becomes brown and viscous. Ctystallize from hot benzene, ob-
taining in this way the double compound C 19 H 16 + QH G , which
crystallizes in colorless crystals, that melt at 76. The benzene
can be expelled by warming the compound on the water-bath,
and the triphenylmethane may be crystallized again from alco-
hol. Yield 25 to 30 grams, if the aluminium chloride is fresh.
The fraction 200 -300 consists mainly of diphenylmethane
(see 51, P- 57)-
Triphenylmethane crystallizes iu rhombic crystals, which melt
at 92. It boils at 358-359. It is easily soluble in ether, chlo-
roform, and hot alcohol, difficultly soluble in cold alcohol.
If a little of the hydrocarbon is dissolved in cold fuming nitric
acid, and the solution poured into water, tfinitrotriphenylmethane
is obtained. This may be reduced to the amino compound by
zinc dust and glacial acetic acid. The amine may be precipitated
from the filtered and diluted solution by ammonia. If the amine
is heated carefully on platinum foil, with a drop of concentrated
hydrochloric acid, the red color of the chloride of pararosaniiine
will be noticed.
17. Preparation of a Hydrocarbon by the Removal of a Hal-
1 Aluminium chloride may be prepared from aluminium turnings and dry hydro-
chloric acid gas. (Stockhausen and Gattermann, Ber., 25, 3521; Escales, Ibid, 30, 1314.)
Gomberg advises the use of chloriue, (Ber., 33, 3146).
60 ORGANIC CHEMISTRY
ogen atom by Zinc, Triphenylmethyl and triphenylmethyl per-
C 6 H 6X
oxide, C 6 H 6 -C and (C 6 H 5 ) 3 C O-O-C(C 6 H 5 ) 8 .
C.H/
Literature Preparation of triphenylmethyl and triphenylmethyl per-
oxide, Gomberg: J. Am. Chem. Soc., 22, 757; Ber., 33, 3150; 35, 1822;
Schmidlin: Ber., 41, 423; Preparation of triphenylchlormethane, Gomberg:
J. Am. Chem. Soc., 22, 752 ; Norris and Sanders : Am. Ch. J., 25, 54 ; Con-
stitution of triphenylmethyl, Gomberg: Ber., 39 3^745 4> 1847; Gomberg
and Cone : Ann., 37, 142 ; Tschitschibabin : Ber., 37, 4709 5 38, 771 ; 4,
367, 3965; 4 1 * 2421; Baeyer: Ber., 40, 3oS^iJ>chmidlin : Ber., 41, 2471;
Relation between color and constitution* *Curtiss : J. Am. Chem. Soc., 32,
795; Halochromie, Baeyer: Ber., 35> 1189.
2 grams triphenylchlormethajle.
3 grams powderecl zinc.
10 cc. benzene.
Put in a dry test-tube 2 grams of triphenylchlormethane, 3
grams of powdered zinc and 15 cc. of dry benzene. Seal the
tube in the blast and shake at intervals for a day or two. A
dark colored oil will collect in the bottom of the tube as the
reaction progresses. This oil is a double salt of triphenylchlor-
methane and zinc chloride. Test one portion of the solution
with a solution of iodine in benzene to show the unsaturated
character of the triphenylmethyl. Shake another portion of
the solution with air and note the formation of triphenylmethyl
peroxide.
Triphenylmethyl has aroused very great interest and been the
occasion of a very large amount of work on the part of chemists,
not only because in some of its forms it seems to have a trivalent
carbon atom, but also because of the bearing which many of the
facts discovered in connection with it have upon the question
of the relation between color and chemical constitution.
18. Preparation of a Hydrocarbon by Reduction with Zinc
Dust. Anthracene, C 14 H 10 .
Literature Preparation from coal tar, Dumas, Laurent: Ann., 5
10; From toluene, benzene and ethylene at a high temperature, Berthelot:
Ann., 142, 254 ; Behr, van Dorp : Ber., 6, 754 ; By Friedel and Crafts, reac-
HYDROCARBONS 6 1
tion, Perkin, Hodgkinson : J. Chem. Soc., 37> 726; From o-bromobenzyl-
bromide. The paper contains a list of syntheses of anthracene, Jackson:
Am. Chem. J., 2, 384; By distilling alizarin with zinc dust, Graebe,
Liebermann : Ann. Supl, 7 297 ; Baeyer : Ann., 140* 295 ; Graebe and
Uebermann: Ber., x, 49.
1 gram alizarin.
Zinc dust.
Fill a combustion tube as follows : Put near one end a loose
plug of asbestos, then 5 cm. of zinc dust, then a mixture of
one gram of alizarin, with 30 grams of zinc dust, then about 30
cm. of a mixture of zinc dust with about ^ its weight of asbestos,
then a plug of asbestos loosely packed. Rap the tube on the
table to give a quite free channel above the zinc dust, lay the
tube in the combustion furnace, and pass hydrogen from the end
first filled till the air is expelled. Heat the mixture of asbestos
and zinc to bright redness, slowly, beginning at the rear end,
continuing a slow current of hydrogen. Crystallize the anthra-
cene, which sublimes to the front, cooler part of the tube, from
benzene or toluene, and determine its melting-point. Also oxidize
a part of it with chromic anhydride in glacial acetic acid, and
determine the melting-point of the anthraquinone (see 42, p.
103).
Anthracene melts at 216 and boils at 351.
This method of preparing anthracene is of great historical sig-
nificance, as it led Graebe and Liebermann to the discovery of the
character of alizarin, and so, indirectly, led to its synthetical
preparation.
19. Zinc Ethyl,
Literature Frankland: Ann., 95, 28; Beilstein, Rieth: Ibid, 123, 245;
126, 248; Rathke: Ibid, 152, 220; Gladstone, Tribe: Ber., 6, 200; J. Chem.
Soc., 35, 569; Kaulfuss: Ber., 20, 3104; Haase: Ibid, 26, 1053; Arthur
Lachman: Am. Chem. J., 19, 410.
18 grams powdered zinc.
2 grams reduced copper.
20 grams ethyl iodide.
62 ORGANIC CHEMISTRY
Put in a 50 cc. round-bottomed flask 18 grams of powdered
zinc, 1 and 2 grams of copper powder, obtained by reducing fine
copper oxide in hydrogen at a low temperature. Close the flask
with a cork having a small glass tube through it. Heat gently
over a free flame, turning all the time till the mass becomes gray
and loses its luster, but not till there is any sign of fusion. Seal)
the glass tube, and allow to cool.
Bend a glass tube, of such size and length as to replace the
inner tube of a small Liebig condenser, at an angle of 135 near
the end. Insert the tube in the mantle of the condenser, clamp
the latter at an angle of 45 with the horizontal, and connect the
flask containing the zinc-copper couple to the lower end of the
bent tube, with a tightly fitting cork. Pour in through the con-
denser 20 grams of ethyl iodide. Place a test-tube, large enough
to allow a small glass tube to pass into it beside the condenser
tube, over the upper end of the condenser, nearly closing the
mouth of the test-tube with a cork ring or with paper. Pass into
the test-tube a slow current of carbon dioxide, and heat the flask
containing the ethyl iodide and zinc-copper couple on the water-
bath as long as ethyl iodide continues to distil and run back, us-
ually only a short time. Then turn the condenser in such a way that
the main tube of the condenser slants downward, and distil off the
zinc ethyl carefully with a free flame, continuing the current of
carbon dioxide through the test-tube.
By heating on the water-bath, the ethyl iodide reacts with the
zinc, forming ethyl zinc iodide, Zn<^ . On heating to a higher
temperature, zinc ethyl is formed.
/C 2 H 5
+ ZnI 2 .
On account of its spontaneous inflammability on coming to the
air, very great care must be exercised in working with zinc
1 Baker and Adamson's zinc, powdered to pass a 30 mesh sieve, answers well for this
purpose. Arthur L,achman (loc. cit.) prepares a zinc-copper couple by mixing zinc dust
with one- eighth of its weight of fine copper oxide and reducing in a current of hydrogen
at a dull red heat.
HYDROCARBONS 63
ethyl, and it must be kept in sealed tubes, and in a fire-proof case.
Small bulbs can be filled with the substance by preparing them
with a small capillary tube on both sides, filling them with carbon
dioxide, drawing the zinc ethyl up into the bulb, (if drawn by
suction with the mouth a large bulb of some sort should be
interposed), and sealing the tube above the bulb with a blow-
pipe.
Zinc ethyl boils at 118, and has a specific gravity of 1.182
at 1 8. It takes fire spontaneously in the air, or in chlorine, and
decomposes violently with water, giving zinc hydroxide and
ethane.
Zinc ethyl is introduced here because it has frequently been
used for the preparation of hydrocarbons. It was formerly used
for a variety of syntheses but nearly everything which has been
accomplished by its use is now more conveniently effected by other
means. The Barbier-Grignard reaction (p. 65) especially,, has
replaced it for many purposes.
Chapter IV
ALCOHOLS AND PHENOLS
Alcohols are prepared from the halogen derivatives of hy-
drocarbons, by treatment with water, potassium carbonate and
water, silver oxide and water, or potassium or silver acetate,
followed by saponification of the acetic ester of the alcohol,
which is formed. The iodides react more readily than other
halogen derivatives, but bromides are often used.
2RI + K 2 CO 3 + H 2 O .= 2ROH + 2KI + CO 2 .
RI + AgC 2 H 3 2 = R O C a H 3 + Agl.
RO C 2 H 3 O + KOH = R OH + KC 2 H 3 O 2 .
From unsaturated hydrocarbons alcohols can be obtained by
dissolving them in concentrated sulphuric acid, diluting, and
distilling. The method gives secondary and tertiary alcohols
in cases where their formation is possible.
C,,H 2W + H 2 S0 4 - C W H 2M + 2 HSCV
C M H 2W + .HSO, -f H 2 = C tt H 2W + X OH + H 2 SO 4 .
Aldehydes may be reduced to primary alcohols, and ketones
to secondary alcohols. The reducing agents most often used are
sodium amalgam in aqueous solutions, sodium in alcoholic or
moist ethereal solutions, or zinc dust and glacial acetic acid.
The last method gives an acetate, which requires saponificalion.
Amines may be converted into alcohols by the action of
nitrous acid in aqueous solutions. In the aromatic series a diazo
compound is first formed. In the aliphatic series, and especially
in cyclic compounds, unsaturated hydrocarbons are also formed,
and interfere seriously with the yield.
RNH 2 + HN0 2 = ROH + N 2 + H 2 .
/H
R< + HN0 2 = R" -f N 2 -f 2 H 2 O.
X NH 2
In the aromatic series sulphonic acids, and in many cases
ALCOHOLS AND PHENOLS 65
halogen derivatives, may be converted into phenols by fusion
with potassium hydroxide. The reaction is accompanied, in
some cases, by a rearrangement, which interferes with its re-
liability for the determination of structure.
RSO 2 OH + 2KOH = ROH + K 2 SO 3 + H 2 O.
Glycols, that is, alcohols having two hydroxyl groups com-
bined with adjacent carbon atoms, may be prepared, in some
cases, by oxidizing olefires with a cold solution of potassium
permanganate.
R CH R CHOI}
+ O + H,0 = \
R - CH R CHOH
This reaction is of greater importance for the preparation of
dihydroxy acids than for the preparation of glycols, however.
(See Fittig: Ber., 27, 2670.)
Many aromatic aldehydes, on treatment with potassium hy-
droxide and water, are converted into a mixture of the potassium
salt of the corresponding acid, and the corresponding alcohol.
2RCHO + KOH = RCH 2 OH + RCO 2 K.
Barbier 1 and Grignard discovered in 1899-1900 that the organo-
magnesium halides of the type R Mg Br(I) formed
by the action of halogen compounds on magnesium in dry ether
may be used for a great variety of syntheses. Contrary to its
conduct in most other cases the halogen of aromatic as well as of
aliphatic compounds may be replaced by reactions carried out
at or below the boiling-point of ether by this method and it has
practically replaced all reactions for which zinc alkyl compounds
were formerly used. The most important applications of the
Bajbier-Grignard syntheses are the following:
i. Preparation of hydrocarbons, Grignard: Compt. rend., 130,
1322.
R MgBr + HOH = RH + Mg(OH)Br.
R MgBr + R'OH = RH + R'.OMgBr.
The second reaction may sometimes be used for the detection
and even for the determination of hydroxyl in organic com-
1 The reaction has been generally know as the Grienard reaction but it seems to have
been first used bv Barbier (Comn. rend., 128, 110, (1899)), and Grignard undertook the
study of the reaction at the suggestion of Barbier.
66 ORGANIC CHEMISTRY
pounds by measuring the amount of methane liberated when
methyl magnesium iodide acts upon the compound. Tschugaeff:
Ber., 35, 3912 ; Zerewitinoff : Ber., 40, 2023.
2. Preparation of alcohols.
a. By the successive action of oxygen and water on the or-
ganomagnesium halide. Thus pinene chlorhydrate gives bor-
neol:
C 10 H 17 MgCl + O = C 10 H 17 OMgCl.
C 10 H 1T OMgCl + H 2 = C 10 H 17 OH + Mg(OH)Cl.
b. By the action of the organomagnesium halide on a ketone
or an aldehyde,
Rv Rv /CH 3
>CO + CH 3 MgI = >C<
R/ R/ X)MgI
,
-I- H 2 - >C + Mg(OH)I
R/ OMgI R/
,0
or R C< -f CH 3 MgI = R C OMgl ^> R CHOHCH..
X H \ H
Ketones give tertiary alcohols, aldehydes give secondary.
c. By the action of the organomagnesium halide on an ester,
giving a tertiary alcohol.
O
//
C 6 H 5 C OCH 3 + C 6 H 5 MgBr
xOMgBr
= C 6 H 4 -C 6 H 5
SX OCH S
C 6 H 5 - C-C 6 H 5 + C 6 H 5 MgBr
\OCH,
.OMgBr
= C 6 H 5 C-C 6 H B + CH s OMgBr
XQ H
(C 6 H 5 ) 3 COH -h Mg(OH)Br.
ALCOHOLS AND PHENOLS 67
d. From acid chlorides,
/OMgl
CH 3 COC1 + CH 3 MgI = CH 3 C CH S
X)MgI x
CH 3 C CH 3 + CH 3 MgI = CH 3 - C-CH 3 + MgClI
\C1 ^CH,
(CH 3 ) 3 COH + Mg(OH)I.
3. Preparation of aldehydes from orthoformic ester. Grig-
nard: Compt. rend., 138, 92; Gattermann and MafTezzoli: Ber.,
36, 4152.
HC(OC 2 H 5 ) 3 + C c H 5 MgBr = C C H 5 CH(OC 2 H 5 ) 2
+ C 2 H 5 OMgBr.
C 6 H 5 CH(OC 2 H 5 ) 2 + HC1 + H 2 = C 6 H 5 CHO + HC1
+ 2C 2 H 5 OH.
4. Preparation of ketones from a nitrile and an organomagne-
sium halide. Blaise : Comp. rend., 132, 38.
C 6 H 5 CN + C 2 H 5 MgI == C 6 H r - C C 2 H 5
II
N Mgl
C 6 H f - C - C 2 H 5 C 6 H 5 - C - C 2 H 5
II + H 2 = + Mg(OH)I
NMgl NH
C 6 H 5 C C 2 H 5 + H 2 O = C 6 H 5 COC,H 5 + NH S .
li
NH
The literature of the Barbier-Grignard synthesis is very volu-
minous. The following authors have prepared good sr.mma-
ries; Tscheiinzeff : Ber., 37, 2081; C. E. Waters: Am. Chem. J..
33 304; Alex, McKenzie. British Assoc. Report, Section B,
Leicester, 1907. See also Chem. Centralbl., 1901, II, 62, and
Schmidt, Ahren's Sammlung, 10, 67, and 13, 357, complete
bibliography.
20. Preparation of Absolute Ethyl Alcohol, CH 3 CH 2 OH.
Literature. Use of lime, Soubeiran : Ann., 3 356 ; Erlenmeyer : Ann.,
160, 249; Warren: J. Am. Chem. Soc., 32, 698; Use of barium oxide to
indicate the end, Berthelot : Jahresb.. 1862, 392; Use of calcium carbide,
68
ORGANIC CHEMISTRY
Yvon: Compt. rend., 125, 1181; Ostermayer: Chem. Centralbl., '98, I, 658;
Use of benzene, Young: Chem. Centralbl., '03, II, 869; Boiling-point curve
for ethyl alcohol and water, Noyes and Warf el : J. Am. Chem. Soc., 23>
463; Alcoholometric table, Morley: J. Am. Chem. Soc., 26, 1186.
I liter of alcohol.
300 grams lime.
Distillate from the above mixture.
200 grams lime,
i gram barium oxide.
Put 300 grams of good lime in -a 1,500 cc. flask. Add i liter
of ordinary alcohol and allow to stand over night. Place the
Fig. 24.
flask on a water-bath, connect with an upright condenser (Fig.
24) and boil gently for two hours. Then connect with the con-
denser by means of a bent tube and distil away the alcohol,
collecting it in a dry flask. Add to the distillate 200 grams of
lime and about one gram of barium oxide. Allow to stand
over night and then connect with the upright condenser as be-
ALCOHOLS AND PHENOLS 69
fore and boil for two hours or until the barium oxide dissolves
imparting a yellow color to the alcohol. Distil away the alcohol
as before but collect in a distilling bulb connected to the lower
end of the condenser with a tightly fitting cork and having a
calcium chloride tube connected to its side tube to prevent moist
air from entering the bulb. Determine the specific gravity and
strength of the alcohol (p. 32).
The boiling-point of absolute alcohol is 78.3 (Ramsey and
Young: J. Chem. Soc., 47, 640). Its specific gravity at 20 is
0.78932. It will not cause anhydrous copper sulphate to turn
blue even on long standing with it and it will not evolve acety-
lene with calcium carbide.
If turnings of metallic calcium are available, the last portions
of water may be removed more rapidly by warming the alcohol
with these.
Prepare some sodium ethylate by dissolving a piece of sodium
the size of a pea in i cc. of absolute alcohol in a tCbt-ttibe. If
the alcohol is absolute and the solution sufficiently concentrated,
it will solidify on cooling. Notice also that such a solution
darkens rapidly on exposure to the air while a solution of so-
dium hydroxide in pure alcohol darkens slowly, if at all.
21. Preparation of an Unsatnrated Alcohol. Allyl alcohol,
CH 2 = CH -- CH 2 OH. (i.3-propenol).
Literature Berthelot and de Lucca: Ann,.ioo, 359; Cahours and Hof-
mann : Ibid, 102, 285 ; Aronheim : Ber., 7> 1381 ; Tollens, Henninger : Ann.,
156, 134, 142; Tollens: Ibid, 167, 222; Romburgh : Jahresb., 1881, 508;
Bigot: Ann. chim. phys., [6], 23* 464.
200 grams glycerol.
50 grams crystallized oxalic acid.
0.25 gram ammonium chloride.
In a 300 cc. distilling bulb put 200 grams of glycerol, 50 grams
of crystallized oxalic acid, and %. gram of ammonium chloride,
the last being added to decompose any alkali salts present, which
would interfere with the reaction. Insert a thermometer, im-
mersed in the liquid, and connect with a condenser. Heat gent-
ly so that the temperature rises slowly. The portion distilling
7O ORGANIC CHEMISTRY
below 195 consists mainly of dilute formic acid (see 45, p. U5)>
and may be converted into the lead salt by boiling with lead car-
bonate. Collect by itself the portion coming over from 195
to 240. When the latter temperature is reached, cool, add 30
grams of oxalic acid and distil as before.
Unite the distillates (i95-24O) and distil, collecting the por-
tion boiling below 105. Add dry potassium carbonate till the
allyl alcohol separates above, separate and add 10 per cent, of its
weight of powdered caustic potash, and allow the mixture to
stand for some time, until the odor of acrolein has disappeared,
separate and distil, collecting the portion boiling at 9O-96.
In order to remove the last traces of water, it is necessary to dis-
til again, after standing for some time with lime or barium oxide.
Yield 12 to 15 grams.
Allyl alcohol boils at 96.6, and has a specific gravity of
-8573, at 15. When dilute allyl alcohol is treated with bromine
dissolved in a solution of potassium bromide, the dibromide,
CH 2 BrCHBrCH 2 OH, is formed, and the reaction may be used
for quantitative determinations.
22. Preparation of a Phenol by the Decomposition of an Amine
/CH, (i)
through the Diazonium Compound. Paracresol, C 6 H/
X OH (4)
(/>-Methyl phenol.)
Literature Stiideler: Ann., 77, 17; Salkowski: Ber., 12, 1440; Griess:
Jahresb., 1866, 458; Korner: Ztschr. Chem., 1868, 326; Wurtz : Ann., 144,
129; Fittig and Kiesow: 156, 258; Oudemans: Ibid, 170, 259; Southwarth:
Ibid, 1 68, 271 ; Pinette : Ibid, 243, 43.
20 grams paratoluidine.
600 cc. water.
20 cc. concentrated sulphuric acid.
15 grams sodium nitrite.
75 cc. water.
2 grams urea.
30 cc. sodium hydroxide (3 cc. = I gram).
10 cc. concentrated sulphuric acid.
30 cc. water.
ALCOHOLS AND PHENOLS /I
In a one liter flask put 20 grams of paratoluidine, 600 cc. of
water, and 20 cc. of concentrated sulphuric acid. Heat till dis-
solved. Cool to 20 or below, and add slowly, with shaking,
a solution of 15 grams of sodium nitrite, in 75 cc. of water,
keeping the temperature below 20. Allow to stand for a short
time, add 2 grams of urea, connect with a condenser, and distil
over the paracresol with water vapor. For this purpose the flask
is fitted as shown in Fig. 25 with a stopper bearing two glass
Fig. 25.
tubes. One of these should reach nearly to the bottom of the
flask or distilling bulb and should be bent to one side in such
a manner that the escaping steam will give a rotary motion to
the liquid. The fle.sk should be inclined so that the steam w : ll
throw the liquid upward toward the side of the flask and not
into its neck. The second tube connects with the condenser.
The steam is best generated in a two quart can of tin, copper
or galvanized iron. The stopper of the can bears two tubes, one
about a meter long reaching nearly to the bottom of the can,
the other a short bent tube to carry away the steam. The latter
is connected with the longer tube in the flask by means of a
rubber tube. 1 Continue the distillation till the distillate gives
o
no turbidity with bromine water. Add to the distillate 30 cc.
of a strong solution of caustic soda and a little bone-black, and
1 For a simple apparatus for steam distillation, using a reversed condenser, see
Mathews, J. Chein. Soc., 71, 318.
72 ORGANIC CHEMISTRY
concentrate rapidly to about 75 cc. by boiling in a large lip
beaker, covered with a watch-glass, to prevent oxidation. Filter
into a beaker containing 10 cc. of concentrated sulphuric acid
diluted with 30 cc. of water. Cool, and' extract the cresol with
ether, extracting three or four times. Dry the solution for a
few minutes with calcium chloride, pour off, distil the ether
from a water-bath, dry the residue in vacuo over sulphuric acid,
and distil. Yield 15 to 16 grams.
The urea is added to destroy the excess of nitrous acid, which,
if allowed to remain, would interfere seriously with the yield.
Paracresol crystallizes in prisms which melt at 36. It boils
at 201.8, and has a specific gravity of 0.9962 at 65.6. It is
slightly soluble in water. Its aqueous solution gives a blue color
with ferric chloride. There is usually difficulty in getting the
cresol to solidify. In that case a drop may be put in a dry
test-tube, placed in some ether in a small beaker. By blowing
air through the ether the temperature can be lowered to o or
below. When a crystal of cresol obtained in this way is added to
the rest, the whole will solidify.
23. Preparation of an Alcohol of the Aromatic Series by
Treatment of an Aldehyde with Caustic Potash. Benzyl alcohol,
C 6 H 5 CH 2 OH (phenmethylol).
Literature Kraut: Ann.,i52, 129; Busse : Ber., 9, 830; Cannizzaro :
Ann., 88, 129; 96, 246; Herrmann: Ibid, 132, 76; Lauth, Grimaux: Ibid,
i43> 81; Niederest: Ibid, 196, 353; Kachler: Ber., 2, 514; R. Meyer:
Ibid, i4 2394; Graebe: Ibid, 8, 1055.
30 grams benzaldehyde.
27 grams potassium hydroxide.
25 cc. water.
Dissolve 27 grams of caustic potash in 25 cc. of water, add
the solution to 30 grams of benzaldehyde, and shake till an
emulsion is formed. Allow the mixture to stand for 24 hours.
Add enough water to dissolve the potassium benzoate, and ex-
tract with ether. Distil off the ether, dry under diminished pres-
sure with a capillary (see 75, p. 171 and 138), and distil with an
air condensing tube. From the alkaline solution the benzoic acid
ALCOHOLS AND PHENOLS 73
.
may be precipitated and purified by recrystallizing from hot
water. Yield 14 to 15 grams, if the benzaldehyde used is free
from benzoic acid.
Benzyl alcohol boils at 204.7, an d has a specific gravity of
1.0507 at 15.4. It dissolves in 25 parts of water at 17. It
combines with calcium chloride, and cannot be dried by that
agent.
24. Preparation of an Alcohol by the Reduction of a Ketone.
Phenyl methyl carbinol, ' \CHOH, phenethylol (i).
CH/
Literature Radziszewski : Ber., 7, 141 ; Berthelot : Ztschr. Chem., 1868,
589; Emmerling, Engler: Ber., 4, 147; 6, 1006.
10 grams acetophenone.
100 cc. ether.
30 cc. water.
8-10 grams sodium.
Put in a 200 cc. flask 10 grams of acetophenone, 1 30 cc. of
water, and 100 cc. of ether. Add sodium in small pieces, shaking
gently, and cooling the flask with water, till the ethereal solu-
tion no longer gives a turbidity when a drop of it is put in a test-
tube with a dilute solution of phenyl hydrazine acetate (see
p. 89). 8-10 grams of sodium will usually be required. To-
ward the close more water may be added, if the solution of the
sodium takes place too slowly. Separate the ethereal solution,
distil off the ether, dry the residue in vacuo over sulphuric acid,
or by heating on a water-bath under diminished pressure with a
capillary (pp. 171 and 138), and distil. Yield 6 to 7 grams. The
yield is diminished by the formation of the pinacone.
>C C
CH/ | |
OH OH
1 This may be prepared exactly as directed for benzophenone (p. 101), using 12 grams
of acetyl chloride in place of 20 grams of benzo}-! chloride. The yield is about 12 grams
of acetophenone. It melts at 20.5 and boils at 202. Acetophenone may also be prepared
by bringing together equivalent amounts of benzoic acid and acetic acid with some
water, and a little more than the equivalent amount of calcium carbonate, evaporating to
drvness and distilling the residue from a retort or flask.
74 ORGANIC CHEMISTRY
*
Thenyl-methyl-carbinol boils at 202 -204, and has a specific
gravity of 1.013.
25. Preparation of a Tertiary Alcohol from an Ester by Means
of a Magnesium Organic Compound. Barbier and Grignard's
Synthesis, Triphenyl Carbinol. C 6 H 5 C O H.
C.H/
Literature __ Preparation from triphenyl methane, Hemilian : Ber., 7
1206; By Barbier ad Grignard's reaction, Ullmann and Miinzhuber: Ber.,
36, 404; Grignard: Compt. rend., 130, 1322 (alcohols, hydrocarbons); 132,
853 (Organometallic compounds of Mg.) ; 133, 1182 (Compounds from
bromobenzene and esters of ketones) ; Centralblatt, i9 OI > II, 622 (acids
from alkyl halides and carbon dioxide, secondary alcohols from alde-
hydes and tertiary alcohols from ketones and from esters) ; W. Tschelin-
zeff: Ber., 37 2081 (List of reactions); C. E. Waters: Am. Chem. J.,
33 304 (Report and bibliography); Alex McKenzie: British Associa-
tion Reports, Section B. Leicester, 1907.
4.8 grams magnesium ribbon.
100 cc. dry ether.
40 grams bromobenzene.
30 grams ethyl benzoate.
10 cc. sulphuric acid (1:1).
Take 200 cc. of ether which has been dried by distillation
over calcium chloride (p. 175) add 15 grams of phosphorus
pentoxide and allow to stand over night. Pour into a distilling
bulb containing 10 grams of phosphorus pentoxide, boil with
an upright condenser and with the side tube closed, for an hour,
then distil, collecting in a dry distilling bulb attached tightly to
the lower end of the condenser with a cork and having the
side neck directed upward and protected from moisture by means
of a calcium chloride tube. Discard, or use for some other pur-
pose the first 10 cc. of ether collected, also leave about 15 cc. of
ether undistilled in the flask containing the phosphorus pent-
oxide.
Put in a 200 cc. flask 4.8 grams of clean magnesium ribbon,
add a crystal of iodine and 100 cc. of the dry ether, then 40
grams of bromobenzene. Cool with ice-water, if the reaction is
ALCOHOLS AND PHENOLS 75
violent or, if the reaction does not begin, warm gently on a water-
bath connecting the flask, in either case, with an upright con-
denser, the upper end of which is protected by a soda-lime tube.
If magnesium phenyl bromide separates, add more dry ether in
sufficient amount to keep it in solution. When the magnesium
has been dissolved, cool and add through the condenser, drop-
ping it slowly from a dropping funnel, 30 grams of ethyl ben-
zoate which has been allowed to stand for a day with anhydrous
sodium sulphate and distilled. The ethyl benzoate is weighed,
of course, after distillation.
Boil the mixture gently for an hour with an upright con-
denser, cool and pour the mixture into a beaker containing
broken ice and 10 cc. of sulphuric acid (1:1 by volume).
Separate the ethereal layer shake it three times vigorously with
20 cc. of dilute sulphuric acid (5 per cent). Distil off the ether
from a distilling bulb and distil the residue with steam (p. 71)
as long as bromobenzene or ethyl benzoate passes over. Cool,
filter off the triphenyl carbinol, and wash and recrystallize from
alcohol. Yield 15 to 18 grams. Triphenyl carbinol melts at
162. It dissolves in concentrated sulphuric acid with an intense
yellow color.
26. Preparation of a Diacid Alcohol from a Halogen Deriva-
CH 2 OH
tive of a Hydrocarbon. Ethylene glycol, | (Ethanediol).
CH 2 OH
Literature Wurtz: Compt. rend., 43, 199, (1856} Jeltekow: Ber., 6, 558;
Niederest: Ann., 186, 393; 196, 354; Erlenmeyer: Ibid, iQ 2 244; Stemp-
newsky: Ibid, 192, 241; Wagner: Ber., 21^ 1234, 3346; Haworth and
W. H. Perkin, Jr.: J. Chem. Soc., 69, 175.
1 8.8 grams ethylene bromide (three times repeated).
13.8 grams potassium carbonate (three times repeated).
TOO cc. water.
Put in a 200 cc. flask 18.8 grams of ethylene bromide, 13.8
grams of dry potassium carbonate, and 100 cc. of water. Con-
nect with a reversed condenser, and boil* gently till the ethylene
bromide disappears, usually eight to ten hours. Add the same
76 ORGANIC CHEMISTRY
amounts of ethylene bromide and potassium carbonate, and boil
as before. Repeat a third time. The addition of a few small
pieces of wood will help to prevent bumping. Some vinyl bro-
mide, CH 2 = CHBr, escapes during the boiling, and can, if de-
sired, be converted into tribromomethane, by leading through a
bottle containing bromine. If large amounts of glycol are de-
sired, the addition of ethylene bromide and potassium carbonate
may be repeated six times instead of three, but in that case it is
necessary to filter off the potassium bromide, which separates, on
cooling the solution after each boiling.
Concentrate the solution in vacuo over sulphuric acid, pour off
from the potassium bromide which separates, wash the latter
with a little absolute alcohol, and submit the glycol to fractional
distillation. Or the aqueous solution may be distilled at once,
best under diminished pressure, and the distillate used in a new
preparation, since the glycol is quite volatile with water vapor.
Ethylene glycol is a colorless liquid, with a sweet taste. It
boils at 197, and solidifies in a freezing mixture. It is miscible
in all proportions with water and alcohol, but not with ether.
C0 2 H
Platinum black oxidizes it to gly collie acid, |
CH.OH
27. Preparation of a Dihydroxy Compound from an Amine
/OH (i).
through 'the Quinone. Hydroquinone, C 6 H 4 <( (1.4-
N)H( 4 ).
Phendiol).
Literature Workresenski : Ann., 27, 268; Wohler: Ibid, 45> 354;
Nietski: Ibid, 215, 127; Ber., 19, 1467; Schniter: Ibid, 20, 2283; Wohler:
Ann., 51, 152; Strecker: Ibid, 107, 229; Salkowski : Ber., 7, 1010; Hlasi-
wetz: Ann., i75 67; Wesclski and Schuler: Ber., 9 1160; Richter: J.
prakt. chem., [2], 20, 207, (1879) ; Herrmann: Ann., 211, 336; Ekstrand:
Ber., ii, 713; Clarke: Am. Chem. J., 14, 555; Nef : Ibid, 12, 483; Seyda:
Ber., 16, 687; Theory of the preparation, Willstatter and Dorogi: Ber.,
42, 2147.
ALCOHOLS AND PHENOLS
77
10 grams aniline.
250 cc. water.
80 grams (44 cc.) concentrated sulphuric acid.
30 grams sodium pyrochromate.
120 cc. water.
Sulphur dioxide.
Put in a beaker 10 grams of aniline, 250 cc. of water, and
80 grams (44 cc.) of concentrated sulphuric acid. Put the beak-
er in ice-water or a freezing mixture, and cool to 5. Stir the
solution by means of a turbine or hot air motor, and drop in
very slowly a solution of 10 grams of sodium pyrochromate in
Fig. 26.
40 cc. of water. Allow the solution to stand in a cool place over
night, and then add, with stirring and cooling, as before, 20
grams of the pyrochromate, dissolved in 80 cc. of water. The
temperature should not rise above 10 during the addition of
the salt. If the sodium pyrochromate can not be had, very
finely powdered potassium pyrochromate may be used instead.
After five or six hours, pass into the solution, which now con-
ORGANIC CHEMISTRY
tains quinone, C 6 H 4 O 2 , a rapid current of sulphur dioxide 1 - till
the solution smells very strongly of the gas. If the odor of the
gas disappears after two hours, pass in more of the gas and al-
low the mixture to stand again. Extract the solution several
times with ether (see 74, p. 167), distil off the ether, and crystal-
lize the hydroquinone from water, using a little bone-black to
decolorize it, and a little sulphur dioxide to prevent oxidation.
Yield 6 to 8 grams. The yield may be increased by using the
bichromate at first to form aniline black and oxidizing the latter
with lead peroxide, Willstatter and Dorogi : Ber., 42, 2161.
Hydroquinone crystallizes in colorless prisms, which melt at
169. It is soluble in 17 parts of water at 15.
28. Preparation of a Dihydroxyquinone by Fusion of a Sul-
phonic Acid with Sodium Hydroxide and Potassium Chlorate.
Alizarin,
H OH
H
\ O
H
y \co/\/
H H
H
( i .2-Anthraquinonediol ) .
Literature Graebe, Liebermann : Ann., 160, 131; Liebermann: Ber.,
7, 805; A. G. Perkin, Hummel: J. Chem. Soc., 63, 1167; Liebermann,
Graebe : Ann. SupL, 7, 296 ; Ber., i, 49, 104, 106 ; 3> 359 ; Perkin : J. Chem.
Soc., 2, 576, (1876); Gerstl: Ber., 9, 281; Liebermann, Lif schiitz : Ber.,
17, 901 ; Lagodzinski : Ber., 28, 1422, 1427.
10 grams anthraquinone.
25 cc. fuming sulphuric acid (sp. gr. 1.875 at 25).
200 cc. water.
50 grams salt.
1 This is most easily generated by dropping concentrated sulphuric acid into a 40 per
cent, solution of acid sodium sulphite.
ALCOHOLS AND PHENOLS 79
10 grams sodium anthraquinone sulphonate.
40 grams sodium hydroxide.
5 grams water.
3 grams potassium chlorate.
Put in a small flask 10 grams of anthraquinone, and 25 cc
of fuming sulphuric acid (containing 10 to 12 per cent, of the
anhydride; sp. gr. 1.875 at 2 5)- Cover with a small watch-
glass, and heat to 200 -230 in an oil-bath, raising the tempera-
ture to this point slowly, for about two hours, or till a drop of
the solution separates little or no anthraquinone on dilution with
water. Allow to cool, pour into 200 cc. of water, filter, if nec-
essary, and add 50 grams of salt, stir thoroughly and allow
to stand for some time, in cold water, till the sodium anthraqui-
none sulphonate separates. Filter off, press, and dry on porous
porcelain.
In a nickel or iron crucible put 40 grams of sodium hydroxide,
and 5 cc. of water, and warm gently till the mass melts, then
stir in a mixture of 10 grams of the sodium anthraquinone
sulphonate, with 3 grams of potassium chlorate. The latter is
for the purpose of oxidizing to alizarin the hydroxyanthraqui-
none which is formed by fusion with the sodium hydroxide, from
the monosulphonate. Heat gently and stir for five to ten min-
utes, and cool.
The transformation may also be effected with advantage in an
autoclave, or in an iron tube (Mannesmann tube), having a
cap screwed on the end which is made tight with a lead washer.
In that case use 40 cc. of water instead of 5 cc., and heat for
20 hours at 170.
Dissolve the fused mass in hot water, filter, neutralize the hot
solution with hydrochloric acid (150 cc., sp. gr. i.n), filter
off, wash, and dry the precipitated alizarin. The alizarin may
be crystallized from alcohol, glacial acetic acid, or nitrobenzene.
It may also be obtained in beautiful crystals by sublimation.
For this purpose sink a porcelain crucible, about 5 cm. in diam-
eter, in a sand bath to its edge, cover it with a round filter, place
on this a funnel of the same size as the crucible, with the stem
8O ORGANIC CHEMISTRY
closed with a rubber cap, or bit of rubber tubing, with a rod in
it. Having put the alizarin in the crucible, heat gently till the
crystals begin to appear in the funnel. Then remove the flame,
or lower it, and allow the whole to stand till the sublimation
is complete. If the apparatus shown in Fig. 27 is available,
Fig. 27.
better results may be obtained in the sublimation. The apparatus
was designed by Bruhl and consists of a hollow plate which can
be cooled with a current of water and covered above with a
glass dish having a ground edge to fit the plate closely. Yield
2 to 3 grams. By use of an autoclave the yield of crude alizarin
is about 7 grams.
Alizarin crystallizes in long, orange-red prisms, which melt at
289 -290. It boils with some decomposition at 430, but may
be sublimed even at 140. It is almost insoluble in cold water,
easily soluble in alcohol, and ether. It dissolves in alkalies to a
purple solution. In dyeing with it, an aluminium mordant gives
a red, a ferric salt a violet, and a chromium salt a reddish brown.
By distillation with zinc dust, alizarin is reduced to anthracene,
the reaction which first led to a knowledge of its composition.
(Graebe and Liebermann: Ber., i, 49).
Chapter V
ETHERS
Methyl ether, ethyl ether and some of their homologues as well
as some mixed ethers may be prepared by distilling a mixture
of the corresponding alcohols with concentrated sulphuric acid.
The reaction involves two steps which proceed side by side.
ROH + H 2 S0 4 = RHS0 4 + H 2 O.
RHSO 4 + ROH = R O R + H a SO 4 .
In the first reaction the alcohol reacts as a base, in the second
it reacts as an acid.
Krafft has shown that benzene sulphonic acid may be used to
advantage in place of sulphuric acid. Ber., 26, 2830.
Ethers may also be prepared by the action of alkyl halides or
of alkyl sulphates upon the sodium derivative of an alcohol.
C 2 H 5 ONa + C 2 H 5 I =-. (C 2 H 5 ) 2 O + Nal.
C 6 H 5 ON a + (CH 3 ) 2 S0 4 = C 2 H 5 OCH 3 + NaCH 3 SO 4 .
C 6 H 5 ONa + NaCH,SO 4 = C 6 H 8 OCH 8 + Na 2 SO 4 .
29. Preparation of an Ether by Means of Concentrated Sul-
phuric Acid. Ethyl ether, C 2 H 5 O C 2 H 5 .
Literature Theory of etherification, Williamson: Papers on etherifica-
tion; Alembic Club reprint; see also Quart. J. Chem. Soc., 4, 229, (1852) ;
Ann., 77, 37; 8l 73', Nef : Ann., 309, 141; 318, 50; Velocity of the re-
action, Conrad and Bruckner: Z. physik. Chem., 4> 631; Use of sul-
phonic acids, Krafft: Ber., 26, 2829; Combination of ether and of ethyl
alcohol with magnesium bromide, Menschutkin : Z. anorg. Chem., 49, 34 ;
52, 9-
zoo g. alcohol (125 cc.).
180 g. concentrated sulphuric acid (100 cc.).
100 g. alcohol.
Put 100 grams of alcohol in a 500 cc. flask or distilling bulb,
add in portions, with cooling, 180 grams of concentrated sul-
phuric acid. Fit the mouth of the flask with a cork bearing a
82 ORGANIC CHEMISTRY
thistle tube dipping below the surface of the mixture and carry-
ing a stopper through which passes a separatory funnel with a
short stem as shown in Fig. 20, p. 46, also a thermometer dipping
into the liquid and a bent tube connecting with a Liebig's con-
denser. In all cases such connections with the condenser should
be made with a tightly fitting cork stopper and the stopper in the
flask is also best of cork, as ether softens india rubber. Heat
the mixture on a wire gauze or asbestos plate till it reaches a
temperature of 140. Then allow the alcohol to drop in slowly
and boil gently, maintaining a temperature of I4O-I45 by regu-
lating the flow of alcohol and the height of the flame. Allow 100
grams of alcohol to flow into the mixture.
Transfer the distillate to a separatory funnel, add 25 to 50 cc.
of water and enough sodium hydroxide so that after vigorous
shaking the lower, aqueous layer reacts strongly alkaline. In
shaking a mixture of ether and an aqueous solution the stopper of
the separatory funnel should be held firmly in place and after
shaking for a moment the stem of the funnel should be turned
upward and the stop-cock opened to relieve any pressure within.
Allow the liquids to separate in two layers, draw off the aqueous
layer below, add some water and repeat the shaking and sepa-
ration.
Hther is very volatile and mixtures of ether vapor and air
are explosive, hence great care to avoid the neighborhood of
flames must always be observed .in working with ether. In dis-
tilling, efficient condensers fed with cold water should be used
and the distillation must not be so rapid that vapors will escape
from the lower end of the condenser.
Pour the washed ether from the top of the separatory funnel
(why not draw it off below?) into a flask containing 10 to 15
grams of powdered calcium chloride. After some hours or on
the following day filter the ether through a dry filter into a dis-
tilling bulb and distil from a water-bath which is not heated
above 40.
Ether prepared as above still retains small amounts of alco-
hol and of water. The alcohol can not be removed by washing"
ETHERS 83
with water. Metallic sodium in the form of wire will remove
the water but after the water is removed its action on the alco-
hol is very slow. Magnesium bromide 1 will remove both alco-
hol and water very perfectly and absolute ether is best prepared
in this manner. Allow the ether to stand for a day with some
of the powdered magnesium bromide and distil. To the dis-
tillate add some fresh magnesium bromide and distil after three
or four days, on a water-bath not heated above 40. (L. W.
Andrews, loc. cit.).
Ullmann recommends the removal of the alcohol and most of
the water by shaking with 1/6 of its volume of sulphuric acid
diluted with an equal volume of water. The ether may <;hen
be dried with sodium wire.
Pure ether boils at 34.6 and has a density at i5/4 = 0.7191
or at 25/4 = 0.7079.
Ether free from alcohol is not colored by shaking it with
aniline violet, while a color is given to it, if alcohol is present.
The purity of the ether and the amount of alcohol pres-
ent may also be determined by the index of refraction measured
with a Pulfrich, inversion refractometer. For pure ether An-
drews, gives, subject to revision, the values:
N/> at 15 = 1.35514
N^ at 20 - 1.35224
N^at 25 = 1-34933
One per cent, of alcohol increases the index of refraction
at 25 to 1.34992, an increase of 0.00059.
30. Preparation of an Ether from the Sodium Salt of a Phenol
and Dimethyl Sulphate. Anisole. Phenyl methyl ether, C 6 H 5 -
O CH 3 .
Literature Preparation from anisic acid, Cahours: Ann., 41, 68; 48,
65; 52, 327; 74 298; From phenol, potassium hydroxide and methyl iodide,
Cahours : Ann., 78, 227 ; From phenol, sodium hydroxide and dimethyl
sulphate, Ullmann: Ann., 3 2 7> 114; Graebe: 34 208; Ullmann: Organ-
isch-Chemisches Pratikum, p. 160.
1 Prepared by mixing magnesium bromide with 4 or 5 per cent, of ammonium brom-
ide, drying the mixture and heating till the ammonium bromide is expelled. The state-
ments her*- given are from a paper on "The Manufacture of Absolute Hther," read before
the Iowa Section of American Chemical Society at Grinnell, April 30, 1910.
84 ORGANIC CHEMISTRY
1 8.8 grams phenol.
10 grrams sodium hydroxide.
70 cc. water.
24 cc. dimethyl sulphate.
9 grams sodium hydroxide.
1 8.8 grams phenol.
Under a hood with a good draft 1 mix in a 200 cc., not too
thin, round-bottomed flask 18.8 grams of phenol, 10 grams of
sodium hydroxide dissolved in about 70 cc. of water 2 and 24
cc. of dimethyl sulphate. Stopper and shake vigorously, remov-
ing the stopper from time to time to relieve the pressure and
cooling, if necessary, to keep the temperature below 5o-6o.
When the temperature no longer tends to rise, connect with an up-
right condenser and boil for a few minutes, adding more sodium
hydroxide, if necessary to maintain an alkaline reaction. Cool and
separate the solution of methyl sodium sulphate from the anisole
(about 21 grams) by means of a separatory funnel.
To the aqueous solution add 9 grams of sodium hydroxide
and 1 8.8 grams of phenol, connect with a condenser placed at an
angle, since the mixture bumps badly, and boil for 6-7 hours.
On account of the bumping both flask and condenser must be
securely clamped. Add more sodium hydroxide, if necessary,
to maintain an alkaline reaction.
Cool, separate the anisole as before, add it to the first portion,
dry with calcium chloride, filter on a dry filter and distil. Yield
38 grams.
Anisole boils at 155 and has a specific gravity of 0.9878 at
2I/4.
31. Preparation, of an Ether from the Sodium Salt of a Phenol
and an Aryl Halide with Metallic Copper as a Catalyzer. Phenol
/C0 2 H
ether of salicylic acid, C 6 H 4 ^
\0-C 6 H 5
1 Dimethyl sulphate is poisonous and breathing of its vapor must be carefully avoided.
8 II is very convenient to have in the laboratory a solution of sodium hydroxide of
such strength that 3 cc. = i gram NaOH, for many purposes like this. 30 cc. of such a
solution and 40 cc. of water would be used here.
ETHERS 85
Literature. Use of copper as a catalyzer; Ullmann : Ber., 38* 2211 ; Ann.,
355 312; Preparation of phenol ether of chlorosalicylic acid, Ibid, 355t
366, 361 ; Preparation from o-diazonium benzoic sulphate and phenol,
Griess: Ber., 21, 982; Preparation of phenylthiosalicylic acid, Goldberg:
Ber., 37, 4526; Preparation of phenylanthranilic acid, Goldberg: Ber.,
39> 1691; Of triphenylamine, Goldberg and Niemerovsky: Ber., 40, 2448.
1.53 gram sodium.
30 cc. methyl alcohol.
13 grams phenol.
5.1 grams o-chlorobenzoic acid.
o.i gram copper powder.
In a 100 cc. flask dissolve 1.53 gram of sodium (2/30 mol.) in
30 cc. of absolute methyl alcohol. Add 13 grams of phenol and
5.1 gram (1/30 mol.) of chlorobenzoic 1 acid and expel the methyl
alcohol at first on the water-bath and then by heating gently on
an asbestos plate. Add o.i gram of copper powder and heat at
180 till the mass becomes solid. Cool, dissolve the mass in
water with the addition of a little sodium carbonate, filter, ex-
tract the excess of phenol with ether, warm the aqueous solution
for a short time in a porcelain dish or beaker to expel the ether,
precipitate the phenyl ether of salicylic acid which has been
formed with hydrochloric acid, filter it off and crystallize it
from dilute alcohol.
The phenyl ether of. salicylic acid crystallizes in leaflets which
melt at 113. It is converted quantitatively into xanthone,
s co \
C 6 HX /C 6 H 4 , by warming on the water-bath with concen-
o/
trated sulphuric acid. (See 44, p. 105.)
1 This may be prepared by Sandmeyer's reaction (p. 201) from anthranilic acid. The
yield is 70 to 80 per cent.
Chapter VI
ALDEHYDES, KETONES AND THEIR DERIVATIVES
Aldehydes are prepared by the oxidation of primary, ketones
by the oxidation of secondary alcohols, the oxidizing agent be-
ing, usually, potassium or sodium pyrochromate and dilute sul-
phuric acid, at moderate temperatures. Beckmann's mixture
consisting of 60 grams (i molecule) of potassium pyrochromate
( or 54 grams of sodium pyrochromate), 50 grams (2.5 mole-
cules) of concentrated sulphuric acid, and 300 cc. of water, is
most generally suitable. (Ann., 250, 325.)
R x R\ /OH R x
>CHOH + O = >C< = >C = O + H 2 0.
R/ R/ X)H R/
Aldehydes are prepared by distilling a mixture of a calcium
or barium salt of an acid, with calcium or barium formate, ke-
tones by distilling a calcium salt of an acid, or a mixture of cal-
cium or barium salts. Bibasic acids, in which the two carboxyl
groups are separated by four, five or six carbon atoms, give cy-
clopentanone, hexanone, or heptanone, and their derivatives by
the same method. In most cases it is not necessary to prepare
the calcium salt, but a mixture of the acid with a considerable
excess of quicklime may be used instead. As with most py-
rogenic reactions, the yields are considerably below the theoreti-
cal, and seconda-y reactions, causing the formation of alcohols
and other products, take place.
In the aromatic series, aldehydes may be prepared by treating
hydrocarbons with chromyl chloride, followed by water. The
hydrocarbon and chromyl chloride are diluted with carbon bi-
sulphide, aud great care must be used to avoid accidents. (ICtard:
Ann. chim. phys. [5], 22, 225; Bornemann : Ber., 17, 1464.)
/O CrCl 2 OH
RCH 3 + 2CrO,Cl 2 = R - CH<
X O - CrCl 2 OH
ALDEHYDES, KETONES AND THEIR DERIVATIVES 87
/O CrCl.OH /OH
R CH< -f H 2 = RCHO + 2CrCl/
X) CrCl 2 OH X OH
Monochlor derivatives having the group CH 2 C1 are often con-
verted into aldehydes by boiling with an aqueous solution of
some nitrate.
/H
R CH 2 C1 + O = R C< + HC1.
Ketones are prepared by the action of chlorides of acids
on zinc alkyls, or in the aromatic series, on hydrocarbons in the
presence of aluminum chloride.
R ^OZnR .
RCOC1 -f Zn/ " = R C R
XR \ci
xOZuR
R - C R + RCOC1 2 R CO-R + ZnCl,.
NCI
or
/0 ZnR
R C R + H,0 = R CO - R + Zn< + RH.
\ci Xci
RH + RCOC1 + A1C1, = R CO R + HC1 + A1C1,.
Practically, the use of zinc alkyl compounds has been displaced
by the organomagnesium compounds as used in the Barbier-
Grignard reaction (p. 67).
Ketones are prepared from acetoacetic ester and similar com-
pounds by the "ketonic decomposition." (See p. -112.)
Aldehydes and ketones may be prepared by warming an a-
hydroxy acid with lead peroxide and sulphuric acid. (Baeyer:
Ber., 30, 1962; Noyes and Shepherd: Am. Chem. J., 22, 264.)
RCHOHCCXH + PbO 2 + H,SO 4 = R CHO + PbSO 4
+ C0 2 + 2 H 2 0.
88 ORGANIC CHEMISTRY
*
R \
>COH.C0 2 H + Pb0 2 + H 2 SO 4 =
R'
R
R
\
>
/
CO + PbSO 4 -}- CO 2 + 2H 2 O.
The sodium salts of aliphatic nitro compounds are decomposed
by acids with the formation of aldehydes or ketones. (Nef:
Ann., 280, 267.)
2R CH=NO ONa + 2HC1 = 2R CHO + 2NaCl
+ N 2 + H 2 0.
Many glyoxylic acids are decomposed by heat with the for-
mation of aldehydes. (Bouveault: Bull. soc. chim. [3], 17,
363.) Glyoxylic acids may be prepared by the method of Ver-
ley, p. 107.
RCOCO 2 H = R CHO + CO 2 .
In the aromatic series, aldehydes may be prepared by the
careful oxidation of cinnamic acid and its derivatives, in alka-
line solution, by means of potassium permanganate. This is in
some sense the reverse of the preparation of cinnamic acid from
benzaldehyde.
R CH=CH CO 2 H + 40 = R CHO + 2CO 2 + H 2 O.
(Einhorn: Ber., 17, 121.)
Quinones are usually prepared by the oxidation of aniline and
its homologues, having a hydrogen atom, or a hydroxy or
amino group in the para position to the amino group. Po-
tassium or sodium pyrochromate and sulphuric acid are usually
employed. In some cases, (e. g., anthracene), a hydrocarbon can
be oxidized directly to a quinone. The reaction in the case of
compounds containing the amino group is complicated, and can-
not be expressed by a simple reaction (see 27, p. 76).
Aldehydes and ketones are very reactive bodies, passing readi-
ly into alcohols and acids by reduction, or oxidation, and con-
densing very easily with a great variety of other substances,
which makes them especially valuable for synthetical purposes.
The most characteristic condensation products, and those most
ALDEHYDES, KETONES AND THEIR DERIVATIVES 89
often used for purposes of identification and purification, be-
cause of their crystalline character, are the double compounds
with acid sulphites of the alkali metals; the phenylhydrazones,
(E. Fisher: Ber., 17, 572; 21, 984; 22, 90) ; Oximes, (V. Meyer
and Janny: Ber., 15, 1324, 1525); And the semicarbazones,
(Baeyer: Ber., 27, 1918; Thiele and Stange: Ann., 283, i ; Thiele
and Heuser; Ibid, 288, 311).
OH
R R /
NcO -f NaHSO 3 = Nc SO 3 Na.
R/ R/
Double compound with
hydrogen sodium sulphite.
:>
:0 -f C 6 H 5 NHNH 2 = >C=N NHC 6 H 5 -f H 2 O.
R/
Phenyl hydrazone
R x R\
>CO -f NH 2 OH = >C=NOH + H 3 O.
R/ R/
Oxime.
CO -f NH 2 NH CO NH 2 =
R \
>C = N NH CONH 2 + H 2 O.
R/
Semicarbazone.
32. Preparation of an Aldehyde by Oxidation of a Primary
/H
Alcohol. Acetaldehyde, CH 3 C< (Ethanal).
Literature Liebig: Ann., 14, 133; Ritter: Ibid, 97, 369; Stadeler:
Jahresb., 1859, 329; J. prakt. Chem., 76, 54, (1859); Bourcart ; Z. anal.
Chem., 29, 609; Rogers: J. prakt. Chem., 4, 240, (1847); Weidenbusch:
Ann., 66, 152; Limpricht: Ibid, 97, 369; Tollens: Ber., 14, 1950; Orndorff
and White : Am. Chem. J., 16, 43.
150 grams (81 cc.) concentrated sulphuric acid.
300 cc. water.
90 ORGANIC CHEMISTRY
100 grams sodium pyrochromate.
150 cc. water.
75 grams (95 cc.) alcohol.
Put in a one liter distilling bulb 300 cc. water, and 150 grams
(81 cc.) of concentrated sulphuric acid. Dissolve 100 grams
of sodium pyrochromate in 150 cc. of water, and add 75 cc. of
alcohol. Put a stopper bearing a separatory funnel in the mouth
of the distilling bulb, and connect a second 250 cc. distilling
bulb to its side tube with a rubber stopper. Connect the side
tube of the second bulb to a condenser which is directed upward,
by running the side tube into a piece of rubber tubing drawn over
the lower end of the condenser. Connect the upper end of the
condenser with two wash-bottles fitted with cork stoppers, or
with two Dreschel wash-bottles each containing about 25 cc. of
Fig. 28.
dry ether. Surround the latter with a freezing mixture. Put the
small distilling bulb into a dish containing water at 45-5O, and
feed the condenser with water at 30. Heat the dilute sulphuric
acid* nearly to boiling, remove the flame, and drop in the pyro-
chromate mixture slowly. The reaction may proceed as rapidly
as is possible without escape of aldehyde through the ether.
Outside heating is not usually necessary after the reaction has
commenced.
ALDEHYDES, KETONES AND THEIR DERIVATIVES 91
When all the mixture has been added and the aldehyde driven
over, by heating for a short time, disconnect the wash-bottle,
transfer the ethereal solution to a flask, set the latter in a freez-
ing mixture, and pass in ammonia gas, generated by boiling
strong aqua ammonia (0.90 sp. gr.), and dried by passing it over
quicklime, or soda-lime in a drying cylinder. Use a wide de-
livery tube for the gas to prevent its being stopped by the alde-
hyde ammonia, CH 3 CH , which is formed. Pass the gas
\NH 2
till the solution smells strongly of ammonia, and allow the whole
to stand for an hour. Filter off the crystals, and allow them to
stand on filter paper for a short time. They can be kept for
some time in tightly stoppered tubes or bottles, containing am-
monia gas. Yield about 15 grams.
Aldehyde may be prepared from the crystals by dissolving
them in their own weight of water, and dropping the solution into
4 parts of 50 per cent, sulphuric acid, condensing the aldehyde
which is generated, with a condenser containing ice-water, and
collecting in a flask surrounded with a freezing mixture.
Aldehyde boils at 21, and has a specific gravity of 0.7951
at 10. When warmed with caustic potash it is converted into
a resin. It reduces a cold ammoniacal solution of silver nitrate
(3 grams AgNO 3 , 33 cc. NH 4 OH, sp. gr. 0.90, 30 cc. 10 per cent.
sodium hydroxide), a general reaction for aldehydes. It restores
the color of a fuchsine solution which has been decolorized by
sulphur dioxide. A drop of concentrated sulphuric acid con-
verts it into paraldehyde, C 6 H 12 O 3 , which melts at 10.5, and
boils at 124. Hydrochloric acid gas converts it into a mixture
of metaldehyde, C 6 H 12 O 3 , and paraldehyde. Metaldehyde decom-
poses on standing, being converted partly into paraldehyde and
partly into tetraldehyde, C 8 H 16 O 4 . Paraldehyde and metaldehyde
are probably stereomeric compounds. Orndorft and White, loc.
cit., Hantsch, however, Ber., 40, 4341, considers metaldehyde as
tetramolecular, (C 2 H 4 O) 4 , or hexamolecular, (C 2 H 4 O) 6 .)
92 ORGANIC CHEMISTRY
33. Preparation of a Ketone by the Distillation of a Calcium
Salt. Acetone, (Propanone), CH 3 COCH 3 .
Literature. Preparation from acetates, Liebig: Ann., i, 225; Dumas.
Ann. chim. phys. (2), 49 208; By the dry distillation of wood, Volckel:
Ann., 80, 310; By the oxidation of citric acid, Pean: Jahresb., 1858,
585; From acetyl chloride and zinc methyl, Freund: Ann., 118, u.
20 grams glacial acetic acid.
40 cc. water.
35 grams barium carbonate.
Mix 20 grams of glacial acetic acid with 40 cc. of water in a
not too small porcelain dish, add in portions 35 grams of baiium
carbonate and evaporate the mixture rapidly to dryness on an
asbestos plate, avoiding over heating after the water has been ex-
pelled. Put the dry residue in a hard glass tube 20 cm. long and
25-30 mm. in diameter. Connect with a condenser by means
of cork stoppers and a bent glass tube and distil with a free flame,
holding the burner in the hand to secure uniform heating of the
whole mass. 1 Shake the distillate twice with 2-3 cc. of a concen-
trated solution of potassium carbonate to remove acids, dry with
calcium chloride and distil from a small distilling bulb, using a
water-cooled condenser and collecting the portion boiling at 54-
60, in a dry weighed flask. Weigh the distillate and add to it
2.^/2 times its weight of acid sodium sulphite dissolved in its own
weight of warm water. When the double compound has com-
pletely separated, filter it off on a plate or a Hirsch funnel (p.-
120) suck it as dry as possible, stop the pump moisten with a
few drops of water, suck this off after a few minutes and repeat
a second time. Dry the compound on a filter-paper.
Decompose one gram of the compound by mixing it with one
gram of dry sodium carbonate and 10 cc. of water and distilling.
Test the distillate with the iodoform reaction (p. 207).
Acetone boils at 56.5 and has a specific gravity of 0.7920 at
19.8. It reacts readily with hypochlorites giving chloroform,
or with hypobromites or hypoiodites giving bromoform or iodo-
form.
1 Distillation from a small distilling bulb immersed in a bath of Wood's metal will
tive better yields.
AI45EHYDES, KETONES AND THEIR DERIVATIVES 93
3V
34. Preparation of an Oxime. Acetoxime, ^>C=NOH
CH/
(Isonitroso acetone or propanone oxime).
Literature V. Meyer and Janny: Ber., i5i 1324, 1529; Janny: Ibid,
16, 170; V. Meyer and Wege : Ann., 264, 121; Dodge: Ibid, 264, 185;
Beckmann: Ber., 21, 767; Auwers : Ibid, 22, 604.
15 grams hydroxylamine hydrochloride.
14 grams (17 cc.) acetone.
8 grams sodium hydroxide.
50 cc. water.
*
Put in a 100 cc. glass stoppered bottle, 15 grams of hydroxyl-
amine hydrochloride, and 17 cc. of acetone, and add a solution
of 8 grams of sodium hydroxide in 50 cc. of water. Shake and
cool somewhat, stopper tightly, and allow to stand for twenty-
four hours. Extract the solution three times with about 20 cc.
of ether, the ether being distilled off and used again each time,
because of the volatility of the acetoxime. The last time distil
only about one-half of the ether, transfer the remainder of the
ethereal solution to a crystallizing dish, and allow the ether to
evaporate spontaneously, or better in vacua over sulphuric acid.
As soon as the crystals are dry, transfer to a well stoppered
bottle, as the substance is quite volatile. Yield 14 to 15 grams.
In the preparation of acetoxime, it is necessary to use the so-
dium hydroxide and hydroxylamine in equivalent amounts, as the
acetoxime cannot be extracted from an acid or an alkaline solu-
tion. Auwers has shown, however, that in some cases the for-
mation of an oxime is facilitated by using about three times the
theoretical amount of sodium hydroxide.
Acetoxime crystallizes in prisms, which melt at 59-6o. It
boils at 134.8 under 728 mm. pressure. It is very easily soluble
in water, alcohol, ether, and ligrom. It can be extracted with
ether only from neutral, not from acid, or alkaline solutions. It
is decomposed by boiling with hydrochloric acid into acetone and
hydroxylamine hydrochloride.
94 ORGANIC CHEMISTRY
35. Preparation of a Semicarbazone Compound. Semicarba-
zone of acetone, >C^N NH CONH 2 .
CH/
Literature Thiele and Stange: Ann., 283, 19; Thiele, Lachman and
Heuser: Ibid, 288, 311; Baeyer : Ber., 27, 1918.
70 cc. concentrated sulphuric acid.
20 grams nitrate of urea.
Ice.
20 grams nitrourea.
150 cc. concentrated hydrochloric acid.
' 70 grams zinc dust.
Ice.
Salt.
20 grams sodium acetate.
12 grams acetone.
Put 70 cc. of concentrated sulphuric acid in a beaker and cool
it below o with a freezing mixture. Add 20 grams of dry urea
nitrate, 1 in small portions, stirring, and taking care that the
mixture does not rise above 2-3. Allow to stand for half an
hour, but not after there is much evolution of gas. Pour on
such a quantity of ice that the temperature of the mixture is
about 30. Cool, filter, wash slightly, and suck as dry as possible.
Stir in with 150 cc. of concentrated hydrochloric acid, previously
cooled to o, and containing some pieces of ice. Pour in small
portions, into a mixture of 70 grams of zinc dust, with powdered
ice, keeping the whole in a beaker, or, especially In working with
larger quantities in a granite iron dish, placed in a freezing
mixture. The temperature should be kept at about o, but the
use of much ice in the solution should be avoided, because of the
resulting dilution. After all has been added, allow to stand for
a short time, filter, add salt to saturation, and 20 grams of so-
dium acetate, and filter again, if necessary. These operations
i This may be prepared as follows: Dissolve 12 grams of urea in 12 cc. of water, and
pour the solution into 20 cc. of concentrated nitric acid, diluted with 20 cc. of water. Cool
thoroughly, filter on a plate, and dry on filter paper, or porcelain. 20 to 22 grams should
be obtained.
ALDEHYDES, KETONES AND THEIR DERIVATIVES 95
should be carried through rapidly, and the solution not allowed
to become warm. Add 12 grams (15 cc.) of acetone, stir thor-
oughly, and allow to stand for some hours, if necessary over
night, in a freezing mixture, or til"? the double compound of zinc
with the acetone semicarbazone,
r
>C=N NH CO NH S | ZnCl 2 ,
ICH/ J,
has separated as completely as possible. Filter off, wash with
a little salt solution, and a little ice-water. 16 to 18 grams of the
compound should be obtained.
By adding some benzaldehyde to the filtrate, stirring thor-
oughly, and allowing to stand, a small quantity of the semicar-
bazone of benzaldehyde can be obtained.
To obtain the acetone semicarbazone, digest 15 grams of the
salt with 30 cc. of concentrated ammonia for some time, and fil-
ter.
To 'prepare the hydrochloride of semicarbazine, add to the ace-
tone compound twice its weight of concentrated hydrochloric
acid, and filter through a funnel loosely plugged with asbestos.
Allow the solution to stand in a vacuum desiccator containing
soda-lime and concentrated sulphuric acid, till it evaporates nearly
to dryness. Dry the crystals of the chloride on porous porcelain.
Acetone semicarbazone crystallizes in needles, which melt with
decomposition at 187. It is moderately soluble in cold water,
less soluble in alcohol, insoluble in ether. It reduces an ammo-
niacal silver solution immediately. It is easily decomposed by
mineral acids, even in the cold.
The hydrochloride of semicarbazine, NH a CO NH NH 2
HC1, crystallizes in prisms, which melt at 173 with decomposi-
tion. It dissolves very easily in water, less easily in hydrochloric
acid, and is almost insoluble in alcohol, and ether. It is decom-
posed by heating with acids and alkalies. It condenses readily
with most ketones and aldehydes, forming, usually, well crystal-
lized compounds.
For the preparation of semicarbazones, Baeyer and Thiele re-
96 ORGANIC CHEMISTRY
commend to dissolve the hydrochloride of semicarbazine in a little
water, add the calculated amount of an alcoholic solution of po-
tassium acetate and the ketone, and then alcohol and water to
complete solution. The reaction is complete in a few minutes
in some cases, in others it requires 4 to 5 days. When complete,
the addition of water will usually cause the separation of a sub-
stance which is entirely crystalline.
36. Preparation of an Aldehyde by Treatment of a Monochlor
Derivative of an Aromatic Hydrocarbon with a Nitrate. Benzal-
/H
dehyde, CgH^^ . (Oil of bitter almonds.)
Literature Liebig, Wohler: Ann., 22, i; C'annizzaro: Ibid, 88, 129;
Dumas, Peligot: Ibid, 14, 50; Guckelberger : Ibid, 64, 60; 72, 86; Lauth,
Grimaux: Bull. soc. chim., 7 106; Piria: Ann., 100, 105; Limpricht:
Ibid, 139, 319; Anschiitz: Ibid, 226, 18.
40 grams benzyl chloride.
40 grams barium nitrate.
300 cc. water.
Put in a 500 cc. round-bottomed flask 40 grams of benzyl
chloride, 40 grams of barium nitrate (or 30 grams of calcium ni-
trate, prepared by treating an excess of calcium carbonate with
the theoretical amount of nitric acid, and filtering), and 300 cc.
of water. Connect with an upright condenser, best with a rubber
tube slipped over the neck of the flask, the condenser reaching
well down into the neck of the latter, so that the nitrous fumes
evolved will come but little in contact with the rubber. The
connection must be tight. Put in the top of the condenser a
rubber stopper bearing a tube, which reaches down into the
liquid, and also a tube which will convey the gases coming from
the condenser to the bottom of a 150 cc. bottle, or, better, of a
large tube, closed below. Pass through the first tube a slow
current of carbon dioxide, and boil the contents of the flask gent-
ly, on a wire gauze, for six or eight hours, or till the odor of the
benzyl chloride nearly, or quite disappears. Some such means as
that described for the exclusion of the air is essential to prevent
the oxidation of the aldehyde to benzoic acid.
ALDEHYDES, KETONES AND THEIR DERIVATIVES 97
Extract the benzaldehyde with ether, distil off the latter, and
shake the residue with three or four times its volume of a strong
solution of acid sodium sulphite, 1 in a stoppered bottle. After
some time, filter off the bisulphite compound and wash succes-
sively with a very little water, alcohol, and ether. Put the com-
pound in a distilling bulb with an excess of a' strong solution of
sodium carbonate, and distil with steam. Extract the benzalde-
hyde from the distillate with ether, dry with calcium chloride,
and distil. Yield 10 to 15 grams.
Benzaldehyde melts at 13. fc and boils at 179. It has a
specific gravity of 1.0504 at 15. It oxidizes slowly on standing
.in the air, when pure. It is more stable when it contains hydro-
cyanic acid, which is usually added to the commercial article
for this reason. It dissolves in 300 parts of water, but is easily
soluble in alcohol, and ether.
37. Condensation of an Aldehyde with Itself by Means of Po-
tassium Cyanide. Benzoin, C 6 H 5 CHOHCOC 6 H 5 .
Literature Liebig and Wohler: Ann., 3, 276; Brewer, Zincke : Ibid,
198, 151; Papcke: Ber., 21, 1335; A. Smith and Ransom: Am. Chem.
J., 16, 108.
20 grams benzaldehyde.
2 grams potassium cyanide.
50 cc. alcohol.
40 cc. water.
Boil the mixture given above with an upright condenser for
half an hour. Cool, filter, wash with dilute alcohol, and crystal-
lize from a little hot alcohol. A little more benzoin may be ob-
tained by adding a little more potassium cyanide to the filtrate,
and boiling again for a quarter of an hour. Yield 15 to 18
grams.
Benzoin melts at 134, and boils with some decomposition at
320. By warming on the water-bath for two hours with two
and one-half times its weight of nitric acid (sp. gr. 1.33), with
frequent shaking, it is oxidized to benzil, C 6 H 5 COCOC 6 H 5 .
1 This must be freshly prepared by passing sulphur dioxide into a mixture of acid
sodium carbonate with three parts of water, till the solution smells strongly of the gas
For sulphur dioxide, see p. 78.
7
98 ORGANIC CHEMISTRY
By means of fuming hydriodic acid benzoin may be reduced
to dibenzyl, C 6 H 5 CH 2 CH 2 C 6 H 5 .
38. Oxidation of a Secondary Alcohol to a Ketone. Benzil,
C 6 H 5 COCO-C 6 H 5 .
Literature Preparation from benzoin, Zinin : Ann., 34, 188; Prepara-
tion from i.2-diphenyltetrachlorethane, (tolantetrachloride) and color
reactions with alcoholic potash : Liebermann and Homeyer : Ber., 12,
1975; Rearrangement to diphenyl glycolic acid (benzilic acid), Liebig:
Ann., 25, 27; Zinin: Ann., 31, 329; Staudinger: Ann., 356, 71; Con-
densation with orthodiamines to a quinoxaline, Hinsberg: Ann., 237,
327; Hinsberg and Konig: Ber., 27, 2181; Condensation with ammonia
and aldehydes to glyoxalines, Radziszewski : Ber., i5> 1494, 2706; Pre-
paration, Henle, Anleitung fur das organisch preparative Praktikum, p.
143-
10 grams benzoin.
25 cc. nitric acid (142).
Put in a small flask 10 grams of benzoin and 25 cc. of concen-
trated nitric acid, (sp. gr. 1.42). Heat on the water-bath with
frequent shaking till oxides of nitrogen are no longer evolved
and a few drops of the solution give, on dilution, a precipitate
which after washing and dissolving in alcohol does not reduce
Fehling's solution. Precipitate with water, filter on a plate, wash
and recrystallize from alcohol. Yield 9 grams.
Benzil crystallizes from ether in prisms which melt at 95.
It boils at 346-348, with some decomposition, under atmos-
pheric pressure or at 188 under a pressure of 12 mm. or at 104-
105 under a high vacuum.
When fused with caustic potash and a little water benzil rear-
ranges to diphenylglycolic acid (benzilic acid) (C 6 H 5 ) 2 -C
X C0 2 H
Benzil has been of unusual interest, because of the part which
its compounds have played in the development of the theories of
stereo-chemistry. It forms two monoximes and three dioximes,
to which the following stereomeric formulas have been given :
C 6 H 6 - C - CO - C 6 H 5 , C 6 H 5 - C - CO - C B H 5 ,
II II
HO N N OH
ALDEHYDES, KETONES AND THEIR DERIVATIVES 99
C 6 H 5 - C - C - C 6 H 5 , C.H 6 - C C - C 6 H 5 ,
I! ii ii II
HO N N OH N OH HO N
C 6 H 5 - C C - C 6 H,
II II
HO N HO N
Some have supposed that the differences are due to structural
isomerism and not to stereoisomerism. See Wittenberg and V.
Meyer: Ber., 16, 503; Auwers and V. Meyer: Ibid, 21, 784,
3510; 22, 537, 564, 1985, 1996; Hantsch and Werner: Ibid, 23, n,
1243-
39. Condensation of an Aldehyde with a Ketone and Oxidation
of the Acetyl Group with Sodium Hypochlorite. Cinnamic acid,
C 6 H 5 CH = CHCCXH.
Literature See preparation of cinnamic acid p. 133, also Engler, Leist:
Ber., 6, 254, 257 ; Claisen, Claparede : Ibid, i4i 2461 ; Claisen, Ponder :
Ann., 223, 139; J. G. Schmidt: Ber., 14, 1460; Meister, Lucius and Briin-
ing, D. R. P., 21162, Ibid, 16, 449; Vorlander: Ber., 30, 2261, Ann.,
2 94, 275: Straus, Caspari : Ber., 40, 2698. Foot note 4.
10 grams benzaldehyde.
25 cc. acetone.
10 cc. caustic soda (10 per cent.).
900 cc. water.
In a one liter flask place 900 cc. of water, 10 grams of benzal-
dehyde, 25 cc. acetone and 10 cc. of caustic soda, free from car-
bonate. Mix 'thoroughly by shaking and allow to stand for lour
days, shaking occasionally. The aldehyde and acetone condense
with the formation of benzalacetone, C 6 H 5 CH=CHCOCH 3 ,
and dibenzalacetone, C 6 H 5 CH CH CO CH=CH C 6 H 5 .
Add 200 grams of salt (see 74, p. 167) and filter off and wash
the dibenzalacetone if it is solid, or extract twice with a
small amount of ether, if it is liquid. Distil off the ether ?..nd
fractionate the benzalacetone from a small distilling bulb (see
Fig. 34, P- 171), under diminished pressure. The benzalacetone
distils at I5i-i53 under 25 mm. pressure, at 26o-262 under
760 mm., and melts at 42.
IOO ORGANIC CHEMISTRY
2.5 grams benzalacetone.
12 grams chloride of lime.
15 grams sodium carbonate.
125 cc. water.
To 12 grams of chloride of lime (containing 31 per cent, of
available chlorine) add 50 cc. of water and 75 cc. of a solution
of sodium carbonate (5 cc. = i gram Na 2 CO 3 ). Filter with the
pump and wash once. To the filtrate add 2.5 grams of benzal-
acetone, warm to 80 -90 and shake vigorously. Continue to
warm and shake till the odor of chloroform is no longer apparent.
The benzalacetone should now have passed into solution.
Cool, filter, precipitate the cinnamic acid with sulphuric acid
and recrystallize from hot water. The oxidation is exactly
analogous to that by which chloroform is prepared commercially
from acetone. For the properties of cinnamic acid see p. .134.
The condensation of benzaldehyde with a methyl or methylene
group adjacent to carboxyl is a quite general reaction and may
sometimes furnish a basis for the determination of the structure
of compounds. See Noyes and Shepherd: Am. Chem. J., 22,
265.
40. Preparation of a Phenylhydrazone. Phenylhydrazone of
acetophenone, >C N NHC.H..
Literature E. Fischer: Ber., 17, 5/3; 22, 9O ; 16, 2241; Overton : Ibid,
26, R 18, Reisenegger. Ibid, 16, 661.
5 cc. acetic acid (30 per cent.).
1.5 cc. phenyl hydrazine.
i cc. acetophenone.
Dissolve 1.5 cc. of phenyl hydrazine in 5 cc. of acetic acid
(30 per cent.) in a test-tube, add i cc. of acetophenone, and shake
vigorously till the hydrazone separates in crystalline form. Fil-
ter, wash with water, dissolve in a very small beaker, in a little
hot alcohol, add water till the hot solution begins to grow turbid,
and allow to crystallize.
The hydrazone of acetophenone is very easily obtained and
ALDEHYDES, KETONES AND THEIR DERIVATIVES IOI
purified. In some cases, where there is difficulty in obtaining
a crystalline product, Overton (loc. cil.) recommends to dissolve
the ketone in a little glacial acetic acid, add a slight excess of
phenyl hydrazine, and allow the mixture to stand in the cold till
the hydrazone separates.
Acetophenone phenylhydrazone crystallizes from dilute alcohol
in leaflets, which melt at 105. It is decomposed by concen-
trated hydrochloric acid into phenyl hydrazine hydrochloritie, and
acetophenone. By sodium amalgam, in alcoholic solution, it is
reduced to a mixture of aniline and phenyl methyl carbinamine,
C 6 H 5 CHNH 2 CH., (V-aminoethylphen).
41. Preparation of a Ketone by Condensation of an Acid Chlo-
ride with Benzene by Means of Aluminium Chloride. Benzo-
phenone, CgH-jCOCgH-. (Diphenylmethanone.)
Literature Peligot : Ann. ? i2, 41; Chancel: Ibid, 7*, 279; Otto: Ber.,
3 197; Friedel, Crafts: Ann. chim. phys., [6], i, 510, 518; Zincke : Ann.,
i59, 377; Friedel, Crafts, Ador : Ber., 10, 1854; Stockhansen and Gatter-
mann : Ber., 25, 3521; Radziewanowski : Ibid, 27, 3235; 28, 1135; Crafts:
Am. Chem. ]., 5, 324 ; Preparation by use of ferric chloride, Nencke and
Stoeber: Ber., 30, 1768.
20 grams benzene.
20 grams benzoylchloride.
100 grams carbon disulphide.
20 grams aluminium chloride.
Put in a flask 20 grams of benzene, 20 grams of benzoyl chlo-
ride, and 100 grams of carbon disulphide. Add in small por-
tions, during about ten minutes, 20 grams of finely powdered
aluminium chloride. (See 16, p. 59.) The chloride should be
exposed to the air as little as possible. Connect with a reversed
condenser, and heat on the water-bath for two to three hours,
or till the evolution of hydrochloric acid nearly ceases. Distil
oft" the carbon disulphide, and pour the residue into 300 cc. of
water in a flask, cooling, if necessary. Add 10 cc. of concentrated
hydrochloric acid, and pass a rapid current of steam through the
liquid foe a short time to expel the rest of the benzene and carbon
disulphide. Collect the benzophenone with some ether, separate,
IO2 ORGANIC CHEMISTRY
wash the ethereal solution by shaking it several times with water,
and with a solution of sodium hydroxide, dry it with calcium
chloride, and fraction the residue, after distilling off the ether,
using a distilling bulb, and collecting the distillate directly m a
test-tube, or preparation tube, without using a condenser. Yield
20 to 21 grams.
Benzophenone melts at 48.5, and boils at
303.7 under 723.05 mm.
304.5 73545 "
305.5 " 750.91 "
306.1 " 760.32 "
306.4 " 765-06 "
This table is of especial value for testing thermometers. (See
P . 28.)
When benzophenone is warmed with hydroxylamine hydro-
chloride, caustic soda in excess, and alcohol, for two hours, an
oxime melting at 140 is formed. If this oxime dissolved in dry
ether, is treated successively with one and a half times its weight
of phosphorus pentachloride, and with water, it is converted into
benzanilide (Beckmann's rearrangement).
C 6 H 5 - C C 6 H 5 + PC1 5 : C,,H 5 - C C 6 H 5 + POC1, -f HC1
II II
NOH N Cl
C 6 H 5 . C C 6 H 6 C 6 H 5 - C - Cl
II II
N Cl N C 6 H 5
C 6 H 5 C - Cl + H 2 C 5 H 5 - C = O
II I + HC1.
N C 6 H 5 HN - C 6 H 5
The study of this reaction has been of great value in the devel-
opment of theories about the stereochemistry of nitrogen. Un-
symmetrical oximes which occur in two forms, as, for instance,
monobrombenzophenone oxime, C 6 H 4 BrCC 6 H 5 , may be rearraug-
II
NOH
ed in this manner, and each form gives a different product : viz.,
brombenzoylanilide and benzoylbromanilide.
ALDEHYDES, KETONES AND THEIR DERIVATIVES 103
C 6 H 4 Br C C 6 H 5 C 6 H 4 BrCONHC 6 H 5 .
II
. NCI
C 6 H 4 Br - C - C 6 H 5 C 6 H 5 CONHC 6 H 4 Br.
II
Cl N
The two compounds can be distinguished by their saponifica-
tion products.
42. Oxidation of a Hydrocarbon to a Quinone. Anthraquin-
/ C0 \
one, C.H/ )>C 6 H 4 .
X CCX
Literature Laurent, Berzelius : Jahresb., 16, 366 ; Anderson : Ann., 122,
301; Kekule, Franchimont : Ber., 5, 908; Ullmann : Ann., 291, 24; W. H.
Perkin, Jr. : J. Chem. Soc., 59> 1012 ; Graebe, Liebermann : Ann. Supl., 7
285.
10 grams anthracene.
17 grams chromic anhydride.
100 cc. glacial acetic acid.
Put 10 grams of anthracene, and 75 cc. glacial acetic acid in a
flask connected with an upright condenser, heat to boiling, and
add, slowly, 17 grams of chromic anhydride, dissolved in the
smallest possible amount of water, and the solution diluted with
25 cc. glacial acetic acid. Boil for five to ten minutes, pour the
solution into water, filter, and wash. Dry the residue, and crys-
tallize it from glacial acetic acid, or from toluene. It may also
be purified by sublimation (see p. ..). Yield almost quantita-
tive, if the anthracene is pure.
Anthraquinone sublimes -in yellow needles, which melt at
273, and boil at 379-38i. 100 parts of toluene dissolve 0.19
parts at 15, and 2.56 parts at 100. By distilling with zinc dust
anthracene is regenerated.
43. Preparation of a Derivative of a Ketone by Condensation
of Phthalic Anhydride with a Hydrocarbon. Orthobenzoylbenzoic
/CO-C 6 H 5
Acid, C 6 H 4 ^ , Diphenylmethanonemethjllic (2) acid.
X C0 2 H
IO4 ORGANIC CHEMISTRY
Literature Plaskuda, Zincke : Ber., 6, 707 ; Behr, vanDorp : Ibid, 7> i? ;
Friedel, Crafts: Ann. chim. phys. [6], 14, 446; Pechmann : Ber., 13* 1612;
Graebe and Ullmann : Ann., 291, 8.
20 grams phthalic anhydride.
100 cc. benzene (free from thiophene).
30 grams aluminium chloride.
In a 300 cc. flask put 20 grams of phthalic anhydride, and
100 cc. of benzene, free from thiophene. Warm till the anhydride
dissolves, and cool. Connect with an upright condenser, and
add, in portions of 3-5 grams, 30 grams of dry, powdered alu-
minium chloride. If the reaction becomes too violent, cool the
flask with water. The whole of the chloride may be added in
ten to fifteen minutes. Warm on the water-bath for two hours.
Cool, add carefully, through the condenser, 80 cc. of cold water,
and 20 cc. of concentrated hydrochloric acid. Distil off the ben-
zene with water vapor, cool, filter, and wash. Dissolve the
acid in 80 cc. of a lO-per cent., solution of sodium carbonate,
filter, and pour into a mixture of 35 cc. of concentrated hydro-
chloric acid, 40 cc. of water, and some pieces of ice. Filter,
and suck dry on a plate (p. 120). In order to obtain the dry o-
/CO-C.H,
benzoylbenzoic acid, C 6 H 4 <^ , this product may be clried
\CO 2 H
at I25-I3O, or it may be dissolved in warm chloroform, sep-
arated from the water swimming on top, the solution dried with
calcium chloride, and the chloroform distilled. The dry acid
may be crystallized from xylene. Yield 22 to 23 grams.
Orthobenzoylbenzoic acid crystallizes from water in long nee-
dles, which contain water of crystallization and melt at 85-
87. It is moderately soluble in hot water, difficultly soluble in
cold water.
When the dry acid is heated to 200, for an hour, with an
equal weight of phosphorus pentachloride, it is converted al-
most quantitatively into anthraquinone.
ALDEHYDES, KETONES AND THEIR DERIVATIVES IO5
44. Preparation of a Ketone Ether by the Condensing Action
xCOv
of Sulphuric Acid. Xanthone, C 6 H/ /C 6 H 4 .
\0/
Literature Preparation by the- oxidation o.f methylene diphenylene-
ketone oxide, Mertz, Weith : Ber., 14* 192; From 2.2'diaminobenzo-
phenone with nitrous acid, Staedel : Ann., 283, 175 ; From salicylic acid
and acetic anhydride, W. H. Perkin : Ber., 16, 339 ; Richard Meyer and
Hoffmeyer : Ber., 25, 2118; By warming salicylic phenyl ether with sul-
phuric acid, Graebe : Ber., 21, 503.
3 grams phenyl ether of salicyclic acid.
20 cc. concentrated sulphuric acid.
Put 3 grams of the phenyl ether of salicyclic acid (31, p. 84)
and 20 cc. of concentrated sulphuric acid in a small flask, heat
for half an hour on the water-bath, cool, pour into about 200
cc. of water, filter off and wash the precipitated xanthone and
recrystallize it from hot alcohol, or, after drying, from benzene.
Xanthone crystallizes in needles which melt at I73-I74. If
dissolves in concentrated sulphuric acid with a yellow color and
intensive blue fluorescence. 'It may be readily converted into
C 6 H 5
/C(OH)v
phenyl xanthenol, C 6 H/ /C 6 H 4 , by the Barbier-Grig-
\ /
nard reaction, Gomberg and Cone: Ann., 370. 173. (See also p.
74.)
Instead of concentrated sulphuric acid phosphorus pentachlo-
ride (to form the acid chloride) followed by aluminium chlo-
ride, (see 41, p. 101) may be used. For naphthalene derivatives
this is essential because of the ease with which they are sul-
phonated. Ullmann : Ann., 355, 349.
Chapter VII
ACIDS
I. Oxidation of Alcohols, Aldehydes, Ketones, and Hydro-
carbons.- The oxidation is usually effected by a mixture of po-
tassium pyrochromate, sulphuric acid, and water, by dilute nitric
acid, or by potassium permanganate in alkaline solution.
With the chromic acid mixture the first product of the oxida-
.tion of an alcohol is probably an aldehyde or ketone. In the
case of ethyl alcohol the aldehyde is so volatile as to escape
rapidly as soon as formed and the method cannot be practically
used for the preparation of acetic acid.
With some of the higher alcohols of the same series the acid
which is formed by the oxidation of a part of the alcohol com-
bines with another portion of the alcohol to form a*n ester. The
continued action of the oxidizing mixture may saponify the ester
and complete the oxidation of the alcohol, but it is sometimes
better to moderate its action so that the ester is the chief product
of the oxidation and to secure the acid by the saponification
of the latter (isovaleric acid).
The oxidation of open chain ketones and of secondary alcohols
can give rise to the formation of acids only by separating the
molecule into two parts. The carbonyl of the ket'one usually,
but not always, goes with the smaller part. There may result
a single acid, as in the case of methyl ethyl ketone (2-butanone),
or two acids, as with dipropyl ketone (4-heptanone or propyl
methyl ketone (2-pentanone). In the latter case, for purposes
of investigation, the separation of homologous fatty acids be-
comes important. This can be effected by distilling an aqueous
solution of the acids. The acid of higher molecular weight
passes over first with the water vapor, apparently because it is
less soluble in water and because of its lower ionization constant,
as the portion of an acid which is ionized can pass over only
to a trifling extent, if at all, with steam. By preparing silver
AQIDS 107
i
salts of the acids in the first and last portions of the distillate
the composition of the acids formed cah be established. (See
47, p. 119), separation of propionic and butyric acids.)
The oxidation of cyclic ketones, and in some cases of other
cyclic compounds, gives rise to the formation of bi-basic acids
(camphoric acid).
In the benzene series, a side chain consisting of allyl (CH 3 ,
C 2 H 5 , etc.) or another group in which a carbon atom is com-
bined directly with the benzene nucleus, can be oxidized to car-
boxyl. In the case of hydrocarbons, the oxidation is usually
effected with difficulty, partly owing to their insolubility in the
oxidizing agents employed. On this account it is sometimes ad-
visable to prepare, at first, a halogen derivative having the halo-
gen in the side chain (Baeyer: Oxidation of paraxylene, Ann.
245, 138; benzoic acid, p. 125).
In a similar manner an acetyl group, COCH 3 , may be con-
verted to the group COCH 2 Br by treatment with bromine in a
solution in carbon bisulphide and the latter may be oxidized
to the glyoxylic group, COCO 2 H, by shaking with a cold, 5 per
cent, solution of potassium permanganate. (Verley: Bull. soc.
chim., 17, 906.) The glyoxylic group is converted into the alde-
hyde group, in some cases, by heat (p. 88) or it may be oxidized
to carboxyl by means of manganese dioxide and sulphuric acid.
The acetyl group may be oxidized to carboxyl with the simul-
taneous formation of chloroform or bromoform by means of so-
dium hypochlorite or hypobromite. (See 39, p. 99.)
II. Saponification of Cyanides. The cyanides of organic radi-
cals, or "nitriles" of acids, may be obtained from halogen de-
rivatives of hydrocarbons, salts of acid sulphuric esters of alco-
hols, or salts of sulphonic acids by treating with potassium
cyanide. The last two cases are applicable only when the cy-
anide formed can be distilled from the dry mixture without de-
composition.
Nef has shown that potassium cyanide has the structure K
N = C, and the reaction probably takes place in two stages :
IO8 ORGANIC CHEMISTRY
ci
K N = e RC1 K
/
--N=CC
L \ R \ x
>C = O + HCN = >C<
R/ X C
N = C R -h KC1.
A small amount of an isocyanide is formed at the same time,
the group r - N = C taking the place of the halogen or acid
group of the organic compound.
Cyanhydrines, which by saponification give a-hydroxy acids,
can be prepared by treating aldehydes or ketones with hydrocy-
anic acid, best in the nascent state:
,OH
R/ R/ N CN
From aromatic amines cyanides can be obtained by treating a
diazonium salt with cuprous cyanide. (Sandmeyer.)
R NH.HC1 + HN0 2 == R - N = N 4 2H 2 O,
Cl
2R N = N + Cu 2 C 2 N 2 = 2R -- CN -f Cu 2 Cl 2 .
Cl
The cuprous cyanide for the reaction is prepared from copper
sulphate.
CuSO 4 + 2KCN : : Cu(CN) 2 + K 2 SO 4 ,
2Cu(CN) 2t = Cu 2 (CN) 2 + (CN) 2 .
The saponification of cyanides is usually effected either by
the action of an aqueous or alcoholic solution of potassium, so-
dium, or barium hydroxide, or by the action of hydrochloric or
sulphuric acid. An amide of the organic acid is probably always
an intermediate product of the saponification and, in some cases,
the conversion of the cyanida into an amide and the conversion
of the latter into the acid may, with advantage, be carried out
in two stages and by means of different agents.
O
R _ c = N + H 2 O = R C NH 2 ,
ACIDS IO9
O O
R _. C NH 2 4- KOH == RC OK -r- NH 2 , or
O O
R - C NH, + H 2 + HC1 = RC - OH -f NH 4 C1.
III. Condensation. By condensation, in general, is meant the
formation of a compound from two others with the elimination
of water, alcohol, ammonia, hydrochloric acid, or two halogen
atoms. 1 Methods of condensation have been especially useful
in the synthesis of acetoacetic ester and its derivatives, of cinna-
mic acid, and of many other compounds in which the same prin-
ciples have been applied.
In the case of acetoacetic ester the condensation appears to
take place as follows :
CH 3 CO.|OC 2 H 5 T H|CH 3 CO 2 C 2 H 5 = CH 3 COCH 2 CO 2 C 2 H 5
-f C 2 H 5 OH.
The researches of Claisen indicate, however, that the action
consists, at first, in the addition of sodium ethylate, formed from
a trace of alcohol which is always present in acetic ester, to the
ester, thus:
-h NaOC 2 H 5 ^ CH 3 C-OC 2 H 5 .
\OC 2 H 5
The addition product then condenses with a second molecule
t)f acetic ester thus:
.ONa
CH 3 C !OC 2 H 5 HJCH.CO 2 C 2 H 5 =
\ J OC 2 H 5
ONa
CH 3 C = CH.CO 2 C 2 H 5 + 2C 2 H 5 OH.
1 Some authors use the term condensation exclusively as applied to reactions in which
carbon atoms unite, and especially with the elimination of water or alcohol, but there
appears to be no logical reason for such a restriction in its use.
HO ORGANIC CHEMISTRY
According to this view, on the addition of an acid a compound
OH
/
of the formula CH 3 C = CH CO 2 C 2 H 5 would be liberated.
A very large amount of work has been done for the purpose
of discovering whether acetoacetic ester and similar compounds
have the "enol" (unsaturated alcoholic) or ketone structure.
It would seem that substances of this character pass very readily
from one form into the other and that while, in some cases,
they may consist exclusively of the one or the other form, in
others they are, in all probability, mixtures of the two forms.
Therefore the compounds in question may react in one or the
other form or in both, according to the reagents used, one form
passing over into the other, as the one or other form disappears
in the progress of the reaction.
Very closely analogous to the preparation of acetoacetic ester
is the preparation of succinylosuccinic ester by the condensation
of succinic ester.
COAH,
NaO CO.C.H. |
\ i ...... or H ........... ? I Na C
I I - ! | C CH,
CH 2 CH, ||
I I ........... c i'S ! CH * C-ONa
C:H 2 p S H S Xi>C ONa \//
I j V -S n S l -'i Q
CO,C,H, ...... I
CO.C.H,
Succinic ester + sodium ethylate. Sodium salt of succinyl-
osuccinic ester.
By the action of sodium ethylate on a mixture of esters or of
esters and ketones or aldehydes, many similar condensations
may be effected. In every case one ester group, after adding
sodium ethylate, condenses with a methyl or methylene group
which is adjacent to the carbonyl of a ketone or of an ester
group. That the methin group (CH) is not susceptible to this
sort of condensation is one of the proofs for Claisen's view, re-
ferred to above (Ber., 20, 651 ; 21, 1154).
ACIDS I I I
Acetoacetic ester and similar compounds which contain a
methylene or methin group between two carbonyl or ester groups
give sodium salts when treated ' with sodium ethylate. In some
cases cyanogen or other groups may have the same effect as car-
bonyl. According to the view now most generally held, the so-
dium is combined with oxygen in these sodium salts ("enol"
form, see above), though some chemists formerly supposed that
it is combined with carbon (ketone form). When these sodium,
silver, or copper salts of acetoacetic ester, malonic ester, and
similar compounds are treated with alkyl iodides, acid chlorides,
or other halogen derivatives, compounds are formed in which
the alkyl or other groups are sometimes combined with carbon
and sometimes with oxygen.
ONa
CH 3 C = CH C0 2 C 2 H 5 -f CH 3 I -
ONa CH 3
/ /
CH, - CI - CH -' CO,C,H 6 ' =
CH.
CH 3 - CO - CH - C0 2 C 2 H 5 + Nal,
Ocu
/
CH 3 CH == CH- CO 2 C 2 H. + CH 3 COC1 -
O COCH 3
CH 3 C = CH C0 2 C 2 H 5 + cuCl. 1
(See Nef : Ann.,266, 103, no, and 287, 270.)
With alkyl iodides, compounds -containing the alkyl com-
bined with carbon are almost exclusively formed.
This method has been of very great value in obtaining deriva-
tives of acetoacetic ester, CH 3 COCH 2 CO 2 C 2 H 5 , malonic ester,
/CO.C.H.
CH./ , and other compounds.
\CO,C,H.
1 In this case " cu " is used to represent an equivalent instead of an atom of copper.
112 ORGANIC CHEMISTRY
Acetoacetic acid and almost all other /?-ketonic acids are ex-
tremely unstable in the free state. Hence, if the esters of these
acids are saponified, decomposition products are usually obtained
instead of the free acid. These products vary according to the
nature of the ester and the means used for its saponification.
In general, saponification with acids causes decomposition with
loss of carbon dioxide and formation of a ketone (ketorric
decomposition) :
CH 3 COCH,CO 2 C a H 3 -f- H 2 SO 4 -f H 2 O =
Acetoacetic ester
CH :J COCH 3 + C 2 H r ,OH -p H 2 SO 4 + CO 2 .
Acetone
(See also Baeyer: Ann., 278, 90, for the saponification of suc-
cinylosuccinic ester.)
Saponification with strong bases, on the other hand, tends to
favor the formation of acids (acid decomposition).
CH S COCH 2 CO,C 2 H, -}- 2KOH : = CH 3 CO 2 K + CH :! CO,K
Hh C,H,OH.
Free malonic acid and its derivatives, that is, all compounds
having two carboxyls combined with the same carbon atom, al-
though stable at ordinary temperatures, are decomposed when
heated to I5O-2OO, and many of them, also, when heated with
moderately strong, not concentrated, sulphuric acid. The value
of acetoacetic ester for synthetic purposes is lessened because of
the difficulty of securing a clean "acid decomposition" and, since
the same product may usually be obtained by the use of malonic
ester, the latter is now more frequently used in syntheses.
/C0 2 C 2 H 5
Cyanacetic ester, CH 2 \ , may be condensed with alkyl
X CN
halides by the same methods used for malonic ester and it seme-
times gives normal products when malonic ester fails to do this.
Thus it may be used to prepare trimethyl succinic acid from
bromoisobutyric ester, (CH 8 ) a CBrCO 2 C 2 H 5 , while malonic ester
gives methyl glutaric ester as the chief product. (Bone and
Spranklin : J. Chem. Soc., 75, 854 ; Noyes : Am. Chem. J., 33,
358.)
ACIDS 113
In some cases the sodium compound of malonic ester may be
prepared and used in a toluene solution to advantage and in
others it is well to employ magnesium ethylate prepared by the
use of magnesium amalgam in alcoholic solution. (Noyes and
Kyriakides: J. Am. Chem. Soc., 32, 1058.)
Another method of condensation used for the preparation of
acids, known as Perkin's synthesis (Perkin: Ann. 147, 230; Ber.,
8, 1599; Jahresb., /#//, 789; Tiemann, Herzfeld: Ber., 10, 68),
consists in heating a mixture of an aldehyde, a sodium salt, and
acetic anhydride. One of the most common illustrations is the
synthesis of cinnamic acid, which appears to take place as fol-
lows :
C 6 H 5 CH ; "+ H 2 ;CHC0 2 Na =, C.H 6 CH=CHCO,Na + H 2 O.
Benzaldehyde Sodium cinnamate
The reaction has been shown lo take place in two stages and
consists, first, in an addition of the sodium salt to the aldehyde
gro.-.p-
O
C 6 H.C^ -f HCH.,CO 2 Na = C 6 H.C-CH 2 CO 2 Na.
' \H - \ H
This addition is followed, under the influence of the acetic
anhydride, by loss of water. The addition always takes [..lace
\viih the methyl, methylene or methin group adjacent to the
carboxyl. Unlike the acetoacetic ester syntheses, the addition
may take place with a methin group as well as with methyl and
methylene groups, but in that case there can be no loss of water,
and a hydroxy acid is formed. This is one of the most im-
portant proofs that the course of the reaction is as given. His-
torically this reaction was first used in the synthesis of cumarin
by Perkin. Later, cinnamic acid and its derivatives became of
especial interest because of -their use by Baeyer in the synthesis
of indigo.
Knoevenagel (Ber., 27, 2345; Ann., 281, 104) discovered a
similar synthesis in which formaldehyde is used, and condensa-
114 ORGANIC CHEMISTRY
tion takes place under the influence of some organic base. The
mechanism of the reaction is not clearly understood.
Another similar condensation, but one which does not lead
to the formation of an acid, is that of formaldehyde, with de-
rivatives of benzene and its homologues, under the influence of
concentrated' sulphuric acid.
N0 2
2C 6 H 5 N0 2 + CH 2 = C 6 H 4 CH 2 C 6 H 4 NO 2 + H 2 O.
(Schopff: Ber., 27, 2321.)
IV. Decomposition of Bibasic Acids. This method of prep-
aration is used in connection with the synthesis by condensa-
tion of derivatives of malonic acid. In the case of acids where
the two carboxyl groups are not combined with the same car-
bon atom, a clean decomposition cannot usually be effected by
heat alone. In some cases, however, one of the carboxyls may
be removed by heating the barium salt of a bibasic acid with
sodium methylate (Mai: Ber., 22, 2136).
The decomposition of oxalic acid may be considered as a
special case under this head:
CO,H
= HCO.H -f C0 2 .
CO,H
The decomposition effected by heat alone is unsatisfactory
in this case, also, and heating with glycerol is practically used.
xOCHO
The glycerol appears to form an ester, C 3 H 5 < , with
\OH),
the formic acid as it is formed. This ester then decomposes
with the water present, yielding formic acid and regenerating
the glycerol.
V. Preparation from Natural Products. Many acids, as stear-
ic, oleic, succinic, benzoic and others, occur in nature in the
form of esters or glucosides, and may be obtained from these
by saponification or decomposition by acids or alkalies.
(C 17 H 3r ,C0 2 ) 3 .C 3 H 5 + 3 KOH = 3 C 1T H,.CO t K + C 8 H 5 (OH),.
Stearin Potassium stearate + Glycerol
ACIDS 115
The preparation of acids by oxidation of other compounds
has already been referred to. Many other illustrations of the
preparation of acids from natural products might be given,
but most of these are individual rather than general, and their
discussion would be out of place here.
45. Preparation of Acids by Decomposition of Bibasic Acids.
Formic acid, H.CO 3 H. (Methanoic acid.)
Literature Berthelot: Ann. chim. phys. [3], 46, 477; Ann., 98, 139;
Seekamp: Ibid, 122, 113; Lorin : Ann. chim. phys., [4], 29, 367; Romburgh:
Compt. rend., 93, 847; Roscoe : Ann., 125, 320; Maquenne: Bull, soc,
chim., [2], 50, 662; Liebig: Ann., 17, 69.
50 grams glycerol.
50 grams oxalic acid.
Place in a 150 cc. distilling bulb 50 grams of glycerol, and
50 grams of crystallized oxalic acid. Insert a thermometer, im-
mersed in the liquid. Connect with a condenser, and heat with
a low flame till the thermometer rises slowly to 105. Allow to
cool to about 50, add 50 grams more of oxalic acid and distil
again, always over a low flame and slowly till a temperature of
115 is shown by the thermometer. Repeat almost indefinitely,
distilling to a temperature of H5-I25. The acid coming over
in the later distillations will be stronger than that of the first.
The residue may be used for the preparation of allyl alcohol
(see 21, p. 69).
Pure formic acid cannot be obtained from the dilute acid by
distillation, the tendency being for a dilute acid to become more
concentrated, or a concentrated acid weaker by distillation, till
an acid boiling at 107 and of 77 per cent, finally passes over.
Weaker acids may be concentrated to this strength by distillation.
A nearly anhydrous acid can then be obtained by dissolving an-
hydrous oxalic acid in this acid with the aid of heat, in such
amount that on crystallizing with two molecules of water it will
somewhat more than combine with all of the water present.
After the oxalic acid has crystallized, the formic acid is poured
off and distilled.
U6 ORGANIC CHEMISTRY
An anhydrous acid may also be obtained by the decomposition
of the lead salt with hydrogen sulphide.
Formic acid melts at 8.3, boils at 101, and has a specific
gravity of 1.2256 at 15. The lead salt, which is easily prepared
by dissolving lead carbonate in the hot dilute acid, is the most
characteristic. It dissolves in 5^/2 parts of hot water, and in
63 parts of water at 16. The copper salt also crystallizes well.
When heated with concentrated sulphuric acid, formic acid
decomposes into water and carbon monoxide. On warming, it
reduces solutions of silver salts with the separation of metallic
silver. On warming with mercuric chloride calomel separates.
On heating the sodium salt with caustic soda, hydrogen is lib-
erated.
The specific gravity of the dilute acid is as follows:
Per cent. CH 2 O 2 Specific gravity at 15
10 .025
30 .080
50 .124
70 .l6l
ioo .223
46. Preparation of an Acid by Oxidation of an Alcohol.
Isovaleric acid (3-methylbutanoic acid).
CH 3 ,
>CH.CH 2 C0 2 H.
CH/
Literature Dumas u. Sfras : Ann., 33, 156; 35, 143; Pierre and
Puchot: Ann. chim. phys., [4], 29, 229; Stalmann : Ann., 147, 129; Er-
lenmeyer u. Hell: Ibid, 160, 275; Duclaux : Compt. rend., 105, 171.
ioo cc. amyl alcohol (3-methyl butanol).
ioo grams sodium pyrochromate. 1 .
200 cc. water.
90 cc. concentrated sulphuric acid.
90 cc. water.
In a one liter flask place ioo cc. amyl alcohol (fusel oil), ioo
grams of powdered sodium pyrochromate, and 200 cc. of water.
Place in the mouth of the flask a stopper bearing a small, up-
1 The use of sodium rather than potassium pyrochromate is advised in this and other
cases because of the greater solubility of the salt.
ACIDS 117
right condenser having a rather wide tube. (Fig. 24, p. 68.)
Add in small portions, through the condenser tube, a cooled mix-
ture of 90 cc. of concentrated sulphuric acid and 90 cc. water.
Shake vigorously and take care that the addition of the acid is
so regulated that the reaction does not become too violent. The
flask may be cooled occasionally by setting it in cold water, if
necessary.
When the acid has all been added and the mixture no longer
tends to grow warm when shaken, remove the condenser and re-
place- it by a stopper bearing two glass tubes, one reaching near-
ly to the bottom of the flask, and the other a short bent tube
leading to a condenser as shown in Fig. 23, p. 71. Distil by
passing into the flask a rapid current of steam.
The oxidation converts a part of the amyl alcohol into valeric
acid, which then combines with another part of the alcohol to
form an ester.
The distillation should be continued as long as the ester con-
tinues to come over. Separate the ester from the aqueous solu-
tion, by means of a separatory funnel, saving both. Put the
ester into a 500 cc. flask with 60 cc. of the aqueous solution and
30 grams of solid caustic soda. Adjust an upright condenser,
as before, and boil gently for fifteen minutes, placing the flask
on a thin asbestos board or on a wire gauze covered with a thin
sheet of asbestos paper. Then add the remainder of the aqueous
solution, which contains some valeric acid, and distil, either di-
rectly or with steam as long as amyl alcohol comes over. The
amyl alcohol, which is recovered, may be saved for use in a new
oxidation. Concentrate the residue in the distilling flask to
about 100 cc. by evaporation in a porcelain dish. Transfer to a
flask, cool, and add 50 cc. of dilute sulphuric acid (1:1 by vol-
ume). Separate the valeric acid by means of a separatory fun-
nel, drawing off the solution below and pouring the acid out of
the top of the funnel into a dry, 50 cc. flask. Add 5 grams of
fused calcium chloride, stopper loosely and warm for ten min-
utes on a water-bath. Cool, pour off the acid into a small dis-
Il8 ORGANIC CHEMISTRY
tilling bulb and distil, using a thermometer and an air condenser
(See Fig. n, p. 26.) Collect in dry test-tubes the fractions:
below 168, i68-i78 and I78-I9O. Clean the distilling bulb
and put in the low boiling fraction and distil till the thermometer
reaches 170, add the second fraction and distil into the same
receiver till the thermometer again reaches 170, then into the
second receiver. Establish two or three new fractions, accord-
ing to the rate at which the thermometer rises as the acid comes
over, the object being to obtain as large a fraction as possible
within an interval of one or two degrees on each side of what
appears to be the true boiling-point of the acid. (See p. 26 for
further details and for corrections for the thermometer.) The
fractional distillation should be repeated till a main fraction is
obtained boiling, in this case, within an interval of one degree.
Yield about 22 grams.
Since ordinary amyl alcohol, or fusel oil, consists chiefly of 3-
3 ,
methylbutanol, >CHCH 2 CH 2 OH, the valeric acid ob-
CH/
tained from it will consist mainly of the acid corresponding to
this formula. Fusel oil contains, however, 10 to 20 per cent.
of what is supposed to be a partially racemic mixture of the 2-
methyl butanols, >CHCH. 2 OH, and these will, of course,
CH/
give the corresponding acids by oxidation. Hence, the valeric
acid prepared from fusel oil, is probably a mixture of at least
two or three chemical individuals. The perfectly pure isovaleric
acid (3-methyl butanoic acid) can be obtained by conversion
of the acid into the barium salt, crystallizing the latter from
water and then separating- the acid from the pure salt.
Pure isovaleric acid is a colorless liquid with an unpleasant
odor. It boils at 176.3 and has a specific gravity of 0.931 at
20. It dissolves in 23.6 parts of water at 20, but the addition
of soluble salts causes most of it. to separate from the solution.
The chromic acid mixture oxidizes it to acetic* acid and carbon
dioxide.
ACIDS I 19
The barium salt crystallizes in small primus or thin leaflets.
The silver salt crystallizes in leaflets soluble in 400 parts of water
at 20, or in 204 parts of water at 80. The salts, when thrown
on water, rotate rapidly. This is characteristic of the salts of
many of the higher fatty acids.
The most serious objection to this preparation is the very un-
pleasant odor accompanying it. The operations should be con-
ducted under a hood as far as possible, and care should be taken
to avoid contact of the valeric acid with the hands or clothing.
47. Oxidation of a Ketone. Separation of Two Fatty Acids.
-Propionic and butyric acids. C,H,CO,H and C,H-CO 2 H (pro-
panoic and butanoic acids).
Literature Papow : Ann., 145, 283; 161, 291; Liebig: Ibid, 7*, 355:
Fitz: Ber., n, 46; Hecht : Ann., 209, 319; Erlenmeyer u. Hill: Ibid, 160,
296; Baeyer: Ibid, 278, 101.
10 grams normal butyric acid (butanoic acid).
25 grams quicklime.
6 grams dipropylketone (4 heptanone).
25 grams potassium pyrochromate.
1 20 cc. water.
20 cc. concentrated sulphuric acid.
Weigh in a small porcelain dish 10 grams of normal butyric
acid. Add carefully, taking care that the mixture does not be-
come so hot as to volatilize any appreciable amount of the acid,
25 grams of powdered quicklime. Mix thoroughly and powder
in a mortar. Place the mixture in a 50 cc. flask, clamp the lat-
ter in a horizontal position, and connect it by means of perforated
cork stoppers and a bent glass tube with a small condenser.
Distil by heating carefully with a free flame. Collect the dis-
tillate in a small flask, add a little dry potassium carbonate to
remove a small amount of acid and water which are present,
weigh, pour off into a 500 cc. flask and weigh again to deter-
mine the amount of crude ketone formed. For six grams of the
ketone add a cooled mixture of 25 grams potassium pyrochro-
mate, 20 cc. concentrated sulphuric acid and 120 cc. of water,
using more or less, according to the amount of thr ketone. Boil
I2O
ORGANIC CHEMISTRY
for three hours on a thin asbestos plate, with a reversed con-
denser (Fig. 24, p. 68). Transfer the mixture to a 200 cc. dis-
tilling bulb and distil in a current of steam (Fig. 25, p. 54), col-
lecting the distillate in successive portions of 10, 25, 50, and 100
cc. Prepare, separately, calcium salts of the acid in the first and
last portions by boiling for a short time with a small quantity
of pure calcium carbonate, and filtering. Concentrate each solu-
tion to 10 cc. or less, and add 5 cc. of a ten per cent, solution of
silver nitrate. Filter off the silver salt, best on a small Witt
plate (Fig. 29), wash, dry, and determine the per cent, of silver
Fig. 29.
in each salt by careful ignition in a. porcelain crucible.
The oxidation gives, in this case, a mixture of propionic and
butyric acids. On distilling the mixture in a current of steam
the butyric acid, which is less soluble and which also has the
lower ionization constant, 1 comes over mainly in the first portion,
while the propionic acid comes over afterwards. A single distil-
lation as directed will usually, when but two acids are present,
give a sufficient separation so that the analyses of the silver salts
leave no question as to the composition of the acids.
Butyric acid boils at 162, and has a specific gravity of 0.978
at o. Propionic acid boils at 141, and has a specific gravity
of 1.013 at o.
1 The ionization constants should be found in Beilstein's Handbuch.
ACIDS 121
100 parts of water dissolve 0.48 parts of normal silver butyrate
and 0.836. parts of silver propionate at 20.
48. Preparation of an Acid from a Natural Product, Stearic
acid, C 17 H 33 CO 2 H.
Literature Pebal : Ann., 91, 138 ; Heintz : Ann., 9 2 > 290 ; C'arnelly, Wil-
liams : Ber., 12, 1360; J. Chem. Soc., 35, 563; Krafft: Ber., 15, 1724; 16,
1722; Saunders: Jahresb., 1880, 831; David: Z. anal. Chem., 18, 622;
Krafft: Ber., 22, 819; Hehner and Mitchell: J. Am. Chem. Soc., iQ> 32.
100 cc. alcohol.
100 grams tallow.
35 grams potassium hydroxide.
35 cc. water.
90 cc. hydrochloric acid (sp. gr. i.i).
Magnesium acetate.
Melt zoo grams of tallow and pour it into a 500 cc. flask, add
100 cc. of alcohol and warm on a water-bath. Add in small por-
tions 35 grams of caustic potash dissolved in 35 cc. of water.
After all has been added, dilute with 200 cc. of cold water. Add
90 cc. of hydrochloric acid (4 cc. = I gram), and warm till the
fatty acids melt and collect on top. Cool and separate the acids
from the solution. Dissolve 'the acids in 500 cc. of warm al-
cohol, cool somewhat, and add enough of a solution of magnesium
acetate 1 to precipitate 20 grams of stearic acid. Stir for five
minutes, filter on a plate, and wash once with strong alcohol.
To the filtrate add the same amount of the acetate, filter on
a new filter, and repeat as often as a precipitate is obtained.
From the last filtrate an impure oleic acid can be precipitated by
water.
Decompose each of the magnesium precipitates separately by
warming and stirring with dilute hydrochloric acid till the fatty
acid separates and melts to a clear liquid, and then allow each to
cool and solidify. Crystallize each portion of the acids obtained
from 15-20 times its weight of strong alcohol. Determine the
1 Prepare the solution by dissolving 16.8 grams of magnesium carbonate or 8 grams of
freshly ignited magnesium oxide in 85 cc. of acetic acid (30 per cent.), filtering, and
washing to a volume of 100 cc. One cc. of the solution will precipitate 1.136 grams stearic
acid.
122 ORGANIC CHEMISTRY
melting-points of each set of crystals obtained, unite portions
having nearly the same melting-point and- crystallize .again, and
repeat till a considerable quantity of pure stearic acid is ob-
tained. It will usually be found best to crystallize rather slowly
by spontaneous cooling, and not to allow the temperature to fall
too low. It is also wise to separate the crystals from the mother
liquors soon after they form, as the mother liquors, in fractional
crystallization will often form supersaturated solutions of the
substance which is to be removed.
The impure oleic acid referred to above may, if desired, be
converted into the lead salt by digesting with litharge on the
water-bath, and the lead oleate separated from the lead salts of
other acids by solution in ether, or in alcohol (of sp. gr. 0.82)
at 65. The oleic acid is set free by digesting the salt with hy-
drochloric acid, the acid converted into the barium salt, and
the latter crystallized from alcohol. (Gottlieb: Ann., 57, 38.)
Distillation under diminished pressure may also be used with
advantage in purifying the fatty acids. The boiling-points and
melting-points are as follows:
BOIUNG-POINTS
Palmitic Stearic Oleic
At 15 mm ............ 215 232 232.5
At 100 mm ......... ... 271.8 291 286
At 760 mm ............ 339-356 359-383
MEETING-POINTS
Palmitic Stearic Oleic
62 69.2 or 7i-7i.5 14
Stearic acid crystallizes from alcohol in leaflets. It is solu-
ble in 40 parts of cold absolute alcohol, in its own weight of
alcohol at 50.
Palmitic acid dissolves in 10 parts of cold alcohol. 100 cc.
of alcohol of sp. gr. 0.8183 will dissolve at o about 0.15 gram
of stearic acid and about 1.2 gram of palmitic acid. (Hehner
and Mitchell.)
49. Oxidation of a Cyclic Ketone. Camphoric acid,
X CO,H
ACIDS 123
Literature Kosegarten : Dissertation, Gottingen, 1785; Laurent: Ann.,
22 135; Wreden: Ibid, 163, 323; Maissen : Ber., 13, 1873; Helle : Dis-
sertation, Bonn, 1893 ; Noyes : Am. Chem. J., 16, 501 ; Aschan : Structur
und Stereochemische Studien in der Campher Gruppe, Helsingfors, 1895,
Structure of Camphor, Komppa : Ann., 37, 209.
/CH,
50 grains camphor, C 8 H U ^ j
X CO
300 cc. nitric acid (sp. gr. 1.42).
200 cc. water.
Place in a one liter flask 50 grams of camphor, 200 cc. of
water and 300 cc. of nitric acid (sp. gr. 1.42). Close the
mouth of the flask with a tube of the form shown in the cut,
filled with water. The tube is easily made by taking a tube
40 cm. long, which will pass easily into the neck of the flask,
sealing it at one end, and blowing a small bulb at about 10 cm.
from the sealed end.
Heat the mixture on a boiling water-bath or a steam-bath for
seventy two hours. Cool, filter off the camphoric acid with the
pump on a Hirsch funnel or a Witt's plate, (Fig. 29, p. 120) using
an "S. & S." hardened filter. After sucking away the mother-
liquors, stop the pump, add enough water to barely cover the
acid, and suck off again. In all cases where the substance to be
washed is appreciably soluble this method should be employed,
as bodies may, in this way, be effectively washed by the use of a
J24 ORGANIC CHEMISTRY
much smaller quantity of the solvent than if the pump is allowed
to act while the solvent is poured over the precipitate. By wash-
ing three or four times in this manner the nitric acid will be
almost completely removed, and the camphoric acid, after dry-
ing, will be sufficiently pure for many purposes, and especially
for the preparation of the anhydride, as the latter is easily puri-
fied by crystallization from alcohol. The acid will, however,
contain some unchanged camphor and, probably, a small amount
,
of camphoramidic acid, C 8 H U <; . If a pure acid is de-
X C0 2 H
sired, after washing once, transfer the acid to a beaker, add 150
cc. of water and 60-65 cc. of ammonia (0.96), enough to convert
the acid into the ammonium salt. Filter the cold solution, and
add it slowly, with constant stirring, to 70 cc. of hydrochloric
acid (sp. gr. i.n, 4 cc. = I gram HC1). Filter on a plate and
wash with cold water. Yield about 30 grams of pure acid.
The acid mother-liquors, if kept separate from the washings,
may be brought up to a specific gravity of 1.29 by the addition
of strong nitric acid and used for a second, and the mother-
liquors of that, for a third oxidation. The yield in the later
oxidations will be somewhat greater. The filtrate from the third
oxidation will contain considerable amounts of camphoronic acid,
C H n (C0 2 H) 3 .
Camphoric acid crystallizes in leaflets or prisms which melt at
187. In a ten per cent, alcoholic solution it shows a rotation
of polarized light [a] y = 4-49 7, or [a]^ = 4-47.8. 100
parts of water, dissolve 0.625 parts of the acid at 12, and
8 to 10 parts at 100. On heating alone, or with acetyl chlo-
ride, or acetic anhydride, it is converted into the anhydride,
/ C0 \
The latter is converted by ammonia into the
ammonium salts of a-camphoramidic and /?-camphoramidic acids,
y CONH 2 / C0
jX which on heating give an imide, C 8 H 14 <^
X C0. 2 NH 4 N
ACIDS 125
The ammonium salt of the a-camphoramidic acid is less soluble
than that of the /3-acid while sodium salt of the /?-camphoramidic
acid is less soluble than that of the a-acid. A separation of the
two acids can be easily effected on the basis of these facts and of
the further fact that both acids are nearly insoluble in water.
50. Oxidation of a Homologue of Benzene with a Halogen Atom
in the Side Chain. Benzoic acid, C 6 H 5 CO 2 H.
Literature. Grimaux, Hauth : Bull. soc. chim., 7, 100; Lunge: Ber.,
10, 1275; Carius: Ann., 148, 51 and 59; Wagner: Jahresb., 1880, 1289;
V. Meyer : Ber., 24, 4251 ; Sandmeyer : Ibid, i? 2653.
20 grams benzyl chloride.
46 grams nitric acid (sp. gr. 1.42).
55 grams water.
Put into a 300 cc. flask with a narrow neck, from which the
lip has been cut off, so as to leave the neck straight to the top,
20 grams of benzyl chloride, 46 grams (32 cc.) of concentrated
nitric acid, and 55 cc. of water. Slip over the neck of the flask
a short piece of rubber tubing, and pass through this the tube of
an upright condenser of such size as to just pass easily into the
neck of the flask. By this means a tight joint is formed, and
at the same time the vapors scarcely come in contact with the
rubber. Place the flask on a wire gauze and boil gently for 2-3
hours, or until the oxides of nitrogen nearly disappear within
the flask, and the benzoic acid formed largely sinks to the bot-
tom of the liquid. There is some tendency for the liquid to
boil explosively, but there is less trouble from this source if a
round-bottomed flask is used and this is heated directly over a
small flame which is brought close to the wire gauze, than if the
flask is heated on a sand bath or on an asbestos paper. A
boiling capillary, (Scudder: J. Am. Chem. Soc., 25, 163) or a
few small pieces of porous porcelain may also be used to ad-
vantage.
Cool, filter on a plate, suck off the mother-liquors, stop the
pump, moisten thoroughly with water and suck off again. Dis-
solve the benzoic acid in 70 to 80 cc. of sodium hydroxide (10
per cent.), added to alkaline reaction, filter on a plain moist
126 ORGANIC CHEMISTRY
filter, or pour off from any benzyl chloride which remains un-
dissolved, put the solution in a flask or large beaker and pass
through it a rapid current of steam till the vapors no longer
smell of benzyl chloride. Precipitate the benzoic acid again by
adding 18 to 20 cc. of concentrated hydrochloric acid. Cool
thoroughly, filter on a plate, and wash once. Crystallize from
a mixture of 30 cc. of alcohol with 10 to 15 cc. of water.
The benzoic acid prepared in this way retains a little chloro-
benzoic acid from which it appears to be nearly or quite im-
possible to free it. This can be detected by heating a little
of the acid, mixed with sodium carbonate, on platinum foil till
it chars, adding a little potassium nitrate and heating again till
white, dissolving the residue in water and adding dilute nitric
acid, and silver nitrate. Yield 13 to 15 grams.
Benzoic acid cvrystallizes in needles or leaflets which melt at
121.4. It boils at 249. 100 parts water dissolve 0.27 part of
the acid at 18, and 2.19 parts at 75. An impure acid is more
easily soluble. It is soluble in about 3 parts of strong alcohol
at 15. It is easily volatile with water vapor. The vapors of
the acid produce a coughing sensation.
51. Oxidation of the Side Chain of a Hydrocarbon Derivative.
/C0 2 H
Ortho- and para-nitrobenzoic acids, C 6 H /
Literature Beilstein : Ann'., 133. 41 ; J 37> 302 ; Hofmann : Ibid, 97,
207; Weith: Ber., 7> 1057; Monnet, Reverdin, Nolting: Ibid, 12, 443;
Nolting, Witt: Ibid, 18, 1336.
40 grams toluene.
50 cc. sulphuric acid (1.84).
30 cc. nitric acid (1.42).
Place in a 300 cc. flask, 40 grams (46 cc.) of toluene and add
in small portions a cooled mixture of 50 cc. of concentrated
sulphuric acid, and 30 cc. of nitric acid (1.42). Shake vigor-
ously and cool after each addition, taking care that the tempera-
ture does not rise above 30. After the acid has all been added,
shake vigorously for ten minutes, keeping the temperature down
ACIDS
127
as before. Pour into about 700 cc. of water. The nitrotoluene
will now sink to the bottom. Separate from the acid liquid with
a separatory funnel, and wash by shaking the nitrotoluene again
with about 100 cc. water. In this and all similar cases where
a heavy liquid is to be separated from water, it is best to use a
flask or separatory funnel of such size that the mixture will
fill it nearly to the top, as otherwise a considerable amount of
the heavy liquid may remain floating on top of the water.
Separate the nitrotoluene as completely as possible from the water,
put it in a small flask, add 10 grams of fused, granulated cal-
cium chloride, and warm in a water-bath with the flask covered
Fig- 31-
with a watch-glass for half an hour, or allow it to stand over
night. Pour the nitrotoluene off into a distilling bulb. Distil, us-
ing a glass tube as a condenser (see Fig. n, p. 26). The portion
distilling below 200 consists principally of unchanged toluene,
and may be saved. That distilling between 2OO-24O consists
chiefly of ortho- and paranitrotoluene, while that boiling above
250 consists chiefly of dinitrotoluene. Ortho-nitrotoluene boils
at 220 and melts at - - 10.5. Paranitrotoluene boils at 239
and melts at 54. The two can be partially separated by frac-
tional distillation, and the para compound can be obtained pure
by crystallization from alcohol. For the remainder of this prep-
aration the mixture boiling from 2oo-24O may be used.
128
ORGANIC CHEMISTRY
15 grams mixed nitrotoluenes.
100 cc. water.
10 cc. sodium hydroxide (10 per cent.).
35 grams potassium permanganate.
350 cc. water.
Arrange a one liter flask with an upright condenser, a bent
thistle tube, and a bent tube to convey steam to the bottom
of the flask, as indicated in the figure. (See Fig. 32.)
Place in. the llask 15 grams of the mixed nitrotoluenes, 100
cc. of water, and 10 cc. of a 10 per cent, solution of sodium
hydroxide. Add about 50 cc. of a warm 10 per cent, solution
Fig- 32.
of potassium permanganate. Pass in a current of steam rapid-
ly till the solution boils, and then just fast enough to keep
the contents of the flask agitated, and so that a small amount
of steam condenses above. Add more of the permanganate
solution at frequent intervals till 35 grams of the salt in all have
been added. Continue the current of steam until the pink color
of the permanganate disappears, or till the drops of nitrotoluene
cease to appear in the condenser. If unreduced permanganate
is still present, add a few drops of alcohol, and shake to reduce
it. Filter hot, from the oxides of manganese, on a filter plate
or Hirsch funnel, and wash twice with water. Concentrate the
filtrate to about 40 cc., and precipitate the mixed ortho- and
ACIDS 129
paranitrobenzoic acids with 25 cc. of concentrated hydrochloric
acid. Cool very thoroughly, filter on a plate, and wash twice
with a very small amount of cold water, sucking off the mother-
liquors thoroughly each time (see 47, p. 120). Convert into the
barium salts by boiling with about 12 grams of barium car-
bonate and 200 cc. of water. Filter hot and cool the filtrate.
A considerable portion of the barium salt of the para acid will
separate. Filter, wash once with cold water and concentrate the
filtrate and washings to a very small volume. Cool quickly and
filter at once on a plate. Moisten the residue several times with
a small amount of cold water and suck off. Concentrate the
filtrate and washings, and crystallize the ortho salt by allowing
the cold, concentrated solution to stand for some time. Recrys-
tallize both the ortho and para salts from hot water, saving the
mother-liquors and working them up in such a manner as to
secure as large an amount as possible of each salt in a pure con-
dition.
The separation of two substances by crystallization is a prob-
lem which often presents itself in organic chemistry, and it
frequently requires very careful work and good judgment to
secure both substances in pure condition without serious loss
of material. As the substance which is present in least amount,
or which is most easily soluble, is liable to form supersaturated
solutions, it is usually advisable to filter off a substance which
has crystallized as scon as its separation from the solution ap-
pears to be practically complete. The separation can frequently
be hastened by vigorous stirring, and by the addition of a frag-
ment of the pure substance, when crystals are slow in starting.
Occasionally, 'however, a substance may form crystals suffi-
ciently large to be separated mechanically from others with
which they are mixed. In such cases the crystallizations must
be allowed to proceed slowly and undisturbed, and it may be
well to allow the solution to evaporate slowly at ordinary tem-
peratures, o-r in vacua over sulphuric acid. Large crystals of
the barium salt of orthonitrobenzoic acid may be obtained in this
way.
9
J3O ORGANIC CHEMISTRY
Crusts which separate on the walls of a dish or beaker dur-
ing evaporation, usually consist of a mixture, and should be
brought back into the solution and redissolved by heating before
the latter is cooled for crystallization. The formation of such
crusts can best be avoided by allowing solutions in volatile sol-
vents, as benzene or alcohol, to stand during crystallization in
tightly closed flasks. Wide mouthed Erlenmeyer or Soxhlet
flasks are very useful for this purpose.
In using a solvent, a very common mistake is to use too large
an amount. A small amount should always be added at first,
unless the properties of the substance are familiar, and then
more, if the substance cannot be brought into solution.
With substances which separate very easily on cooling the so-
lution/ the opposite mistake may be made, if the solution requires
filtration. In such cases, the substance should be taken only in
such amount as will dissolve very easily in the amount of the
solvent used, and care must be taken to prevent the crystalliza-
tion of the substance on the filter, either by the use of a plate,
(not a Hirsch funnel), and pouring only as fast as the solution
runs through the filter, or by the use of a hot water funnel.
The latter is rarely necessary, if the chemist has acquired the
necessary experience, except in cases where a precipitate clogs
the filter badly.
When alcohol is used as a solvent, the yield of crystals may,
sometimes, be increased by adding some water to the solution
before it cools. When the impurities are soluble in dilute alco-
hol, this may be used with advantage instead of pure alcohol
to wash the crystals.
It should be remembered that strong alcohol is not a suitable
solvent for some acids and some nitro-phenols because of the
.ease with which they form esters.
Crystallization is the most valuable means in the hands of the
chemist for obtaining pure substances. When it can be applied,
it almost always gives purer substances than fractional dis-
tillation. In working with new substances, success often depends
largely on the choice and use of proper solvents, and it is a mat-
ter to which the beginner should give very careful attention.
ACIDS 131
In working with new compounds valuable hints can almost al-
ways be obtained by learning from text-books or chemical jour-
nals the conduct of closely related substances which have been
previously known.
Orthonitrobenzoic acid crystallizes in colorless triclinic prisms,
which have a sweet taste, melt at 147, and dissolve in 164 parts
of water at 16.5.
Paranitrobenzoic acid crystallizes in yellow leaflets, which melt
at 240, and dissolve in 1200 parts of water at 17, or in 140
parts at 100.
The barium salt of the ortho acid crystallizes with 3 molecules
of water, in yellow, triclinic crystals, which are easily soluble
in water.
The barium salt of the para acid crystallizes with 5 molecules
of water, in yellow, monoclinic prisms, soluble in 250 parts of
cold, and 8 parts of hot water.
52. Preparation of an Acid from an Amine through a Diazo-
/CH, (i)
nium Compound. Paratoluic acid, C 6 H 4 <(
X C0 2 H (4)
Literature Spica and Paterno: Ber., 8, 441; Sandmeyer : Ibid, 17,
1633, 2653; 18, 1492; Baeyer and Tutein : Ibid, 22, 2178; Herb: Ann.,
258, 8.
21.4 grams paratoluidine.
39 grams concentrated hydrochloric acid.
150 cc. water.
50 grams ice.
14 grams sodium nitrate.
70 cc. water.
55 grams potassium cyanide.
100 cc. water.
50 grams copper sulphate,
loo cc. water.
10 grams tolunitrile.
30 cc. concentrated sulphuric acid.
20 cc. water.
132 ORGANIC CHEMISTRY
In a one liter flask dissolve 50 grams of copper sulphate in
100 cc. of hot water. When the diazonium solution, given be-
low, has been prepared, pour into the solution of copper sulphate,
slowly, while the latter is heated to gentle boiling, in a hood with
a good draught, 55 grams of potassium cyanide dissolved in 100
cc. of water. This converts the copper into cuprous cyanide
with evolution of cyanogen. If the cuprous cyanide solution
turns dark very rapidly, azulmic acid is formed by the decom-
position of cyanogen held in solution. The presence of any ap-
preciable quantity of this azulmic acid acts very unfavorably
on the formation of the nitrile later. By boiling the copper sul-
phate solution gently during the addition of the potassium cy-
anide solution and by continuing the boiling for a few minutes
at the end to expel the cyanogen a perfectly clear, slightly col-
ored solution of cuprous cyanide will be obtained.
Put into a 400 cc. beaker 21 grams of paratoluidine, add 150
cc. of water, and 39 grams (33 cc.) of concentrated hydrochloric
acid (sp. gr. 1.19). Add 50 grams of ice, and when the tem-
perature has fallen nearly to o, add, in small portions, with
stirring a solution of 14 grams of sodium nitrite in 70 cc. of
water. For a discussion of the best condition for Sandmeyer's
reaction see 92, p. 202.
After five or ten minutes, having meanwhile, completed the
preparation of the cuprous cyanide solution, place in the mouth
of the flask containing it a funnel, and pour in the diazonium so-
lution, shaking the flask and keeping it hot on a boiling water-
bath, taking care also that the solution does not froth over. As
soon as all of the solution has been added, distil off the nitrile
in a rapid current of steam (see Fig. 25, p. 71). If the dis-
tillation is sufficiently rapid, the nitrile will come over with
300 to 400 cc. of water. Cool the distillate in ice-water or a
freezing mixture, till the nitrile solidifies, and separate the latter
by quick filtration on a plate, or an a funnel loosely stoppered
with cotton-wool. Care must be taken to transfer the nitrile
to a dish or a bottle before it melts. If thought better, the nitrile
can be brought to the surface by adding salt to the water, or it
ACIDS 133
may be collected with a little ether, and separated with a sep-
aratory funnel. Yield about 15 grams.
Tolunitrile melts at 28.5' and boils at 218.
For 10 grams of tolunitrile take a mixture of 30 cc. of con-
centrated sulphuric acid with 20 cc. of water. Boil in a small
round-bottomed flask on an asbestos plate with an upright con-
denser till crystals of toluic acid appear in the latter. Cool,
dilute, filter. Put the acid in a flask, dissolve in a little alcohol,
and add hot water till the solution becomes turbid. Add 2 or 3
grams of animal charcoal, boil a short time, filter hot, and allow
the acid to crystallize. Yield 8 to 9 grams from 10 grams of
the nitrile.
Toluic acid crystallizes in white needles, which melt at 177.
It is very easily soluble in alcohol and ether, and easily soluble
in hot water. It volatilizes readily with water vapor. In alka-
line solution it is easily oxidized to terephthalic acid by po-
tassium permanganate.
53. Condensation of an Aldehyde with the Sodium Salt of an
Acid. Perkin's Synthesis. Cinnamic acid,
C 6 H 5 CH = CHCO 2 H.
Literature Perkin : Jsb. d. chem., 1877, 789; J. Chem. Soc., 31, 388;
Tiemann, Herzf eld : Ber., 10, 68; Edeleano, Budistheano : Bull. soc. chim.
[3], 3, 191; Michael: Am. Chem. J., 5> 205. Also see preparation, 39-
20 grams benzaldehyde.
30 grams acetic anhydride.
10 grams sodium acetate.
In a 100 cc. flask place 10 grams of recently fused and
powdered, dry, sodium acetate, 30 grams acetic anhydride, and
30 grams benzaldehyde, both recently distilled. Connect with an
upright air condenser tube, I cm. in diameter and 60-80 cm. long.
Heat in a small paraffin bath to the boiling-point of the mixture,
about 180, for eight hours. Pour the contents of the flask
while hot into a 500 cc. flask or distilling bulb. Rinse out with
hot water and then distil with water vapor as long as benzalde-
hyde comes over. Add more water, if necessary, to dissolve
the cinnamic acid, and a little bone-black. Boil and filter hot
134 ORGANIC CHEMISTRY
on a plain or plaited filter, previously moistened. To the filtrate
add 13 cc. of concentrated hydrochloric acid. (Why is this de-
sirable according to the theory of ionization?) The cinnamic
acid will crystallize from the filtrate on cooling. If it does not
have the proper melting-point, recrystallize from hot water.
Cinnamic acid crystallizes from water in colorless needles or
leaflets, which melt at 133. It dissolves in 3500 parts of water
at 17, much more easily in hot water. It combines with bromine
to form a dibromide, C 6 H 5 CHBr.CHBrCO 2 H, which on treatment
with alcoholic potash gives phenyl propiolic acid, C 6 H 5 C C -
CO 2 H. Ordinary cinnamic acid appears to be the cistrans modi-
C 6 H 5 - CH
fication, . Three other forms, one called iso-
H C CO 2 H
cinnamic acid, which melts at 58, one called allocinnamic acid,
which melts at 68, and a fourth isocinnamic acid, which melts
at 42, are known. Since the accepted theory of stereoisomer-
ism will account for only two isomers or stereomers, the exist-
ence of these forms has led to a very careful investigation of
these acids. Liebermann: Ber., 23, 141, 2511; 24, 1102; 25, 950;
26, 1572; 27, 2038; Fock: Ibid, 23, 147, 2511; Ostwald:
Ibid, 23, 516; 24, 1106; Stohmann: Z. physik. Chem., 10, 418;
Michael: Ber., 34, 3640; Erlenmeyer, Jun. : Ber., 38, 3499; 39,
285; Erlenmeyer and Barkow: Ber., 39, 1570; Biilmann : Ber.,
42, 182 ; 43, 568 ; Riiber and Goldschmidt : Ber., 43, 453 ; Lieber-
mann, Ber., 42, 1027.
A final conclusion has not, perhaps, been reached but the pres-
ent tendency is to explain the extra forms on the basis of poly-
morphism.
For a quite different method of preparing cinnamic acid
see 39. P- 99-
54. Reduction of an Unsaturated Acid by Sodium Amalgam.
Hydrocinnamic acid, C 6 H 5 CH 2 CH 2 CO 2 H, ( Phen-3-propanoic
acid).
Literature Alexejew, Erlenmeyer: Ann., 121, 375; 137, 327; Gabriel,
Zimmermann: Ber., is 1680; Fittig, Kiesow : Ann., 156, 249; Sesemann:
Ber., 6, 1086; 10, 758; Conrad, Hodgkinson : Ann., 193, 300; Conrad:
ACIDS 135
Ibid, 204, 174; Conrad, Bischoff: Ibid, 204, 180; Fittig, Christ: Ibid,
268, 122. For benzyl acetone, Ehrlich : Ibid, 187, 11; Jackson : -Ber., 14,
890; Harries, Eschenbach : Ibid, 29, 383.
10 grams cinnamic acid.
60 cc. water.
27 cc. sodium hydroxide (10 per cent.).
135 grams sodium amalgam (3 per cent.).
Put in a 200 cc. wide-mouthed bottle 10 grams of cinnamic
acid, 60 cc. of water, 27 cc. sodium hydroxide (10 per cent.),
and 135 grams sodium amalgam (3 per cent.). 1 Shake for
some time till the amalgam becomes liquid. Take out a few
drops of the solution, dilute, pass carbon dioxide through it, or
add a few drops of hydrochloric acid, a little sodium car-
bonate and then a drop of a very dilute solution of potassium
permanganate. If the permanganate is decolorized or turns
brown at once, cinnamic acid is still present and the solution
must be warmed in a water-bath, shaken occasionally, and, if
necessary, more amalgam added till the solution no longer de-
colorizes permanganate. This permanganate test has proved of
great value for the detection of unsaturated compounds in many
similar cases. The test cannot be applied to the alkaline solu-
tion without passing carbon dioxide through it, because it is
masked by the formation of a green manganate.
When the reduction is complete, pour off from the mercury
and precipitate the hydrocinnamic acid by adding 22 to 25 cc.
of concentrated hydrochloric acid. The acid usually separates
as an oil which solidifies on allowing the cold solution to stand.
Filter off, and recrystallize from hot water. Yield 9 grams.
Hydrocinnamic acid crystallizes in long colorless needles which
melt at 49. It boils at 280. It is easily soluble in boiling
water, in alcohol, and in ether. It is volatile with water vapor,
1 Weigh out in a dry mortar 130 grams of pure mercury (amalgam from impure mer-
cury is much less effVctive; Aschan: Ber. 24, 1865; E. Fischer: fbid. 25, 1255). Cl an 4 grams
of sodium, cutoff a thin slice and press it to the bottom of the mortar with the pestle, and
press gently till the somewhat violent reaction takes place. Add a second piece in the
same way and continue as rapidly as possible till all is added. If the operation is con-
ducted quickly, all can be added before the mass solidifies. Break up the amalgam at
once and transfer it to a tightly stoppered bottle.
136 ORGANIC CHEMISTRY
and solutions of it cannot be concentrated by boiling without loss.
It is soluble in 168 parts of water at 20.
The reduction of an unsaturated acid by sodium amalgam can
only be carried out, apparently, when the double union is adja-
cent to the carboxyl. When the double union is further re-
moved the reduction may often be carried out by first adding
Jiydriodic acid and then reducing with zinc dust or the zinc-cop-
per couple in an alcoholic solution and in presence of a little
dilute acid. See 6, p. 42, also Noyes and Blanchard: Am.
Chem. J., 26, 288.
The reduction may also be effected electrolytically (Elbs:
Uebungsbsp. elektrolyt. Darst. chem. Praparate; see also Bredt:
Ann., 266, 13) ; by ethyl or amyl alcohol and sodium, (Laden-
burg, Baeyer). See Einhorn: Ann., 286, 257; 295, 173; Diels,
Rhodius: Ber., 42, 1072; by hydrogen in the presence of col-
loidal platinum or palladium, Paal and Gerum : Ber., 41, 2273.
For other methods of reduction see Meyer: Analyse u. Konsti-
tutionsermittelung org. Verbindungen, looking up "Reduktion"
in the index.
55. Preparation of an Ester of a Bibasic Acid from a Halogen
Derivative of an Acid. Malonic ester, CH
Literature Dessaignes: Ann., 107, 251; Kolbe and Miiller: Ibid, 131*
348, 350; Finckelstein : Ibid, i33> 338, 350; Conrad: Ibid, 204, 134; Claisen
and Venable : Ibid, 218, 131 ; Kolbe and Miiller : J. Chem. Soc., 17, 109,
(1864); Noyes: J. Am. "Chem. Soc., 18, 1105 (1896); Presence of cy-
anacetic ester in malonic ester, Noyes : J. Am. Chem. Soc., 23, 397 ;
Preparation of cyanacetic ester, Ibid, 26, 1545.
50 grams monochloracetic acid.
45 grams acid sodium carbonate.
100 cc. water.
40 grams potassium cyanide.
100 cc. alcohol.
80 cc. concentrated sulphuric acid.
Put 50 grams of monochloracetic acid into a porcelain dish
ACIDS 137
20 cm. in diameter. Add 100 cc. of water, and 45 grams of acid
sodium carbonate. Warm, stirring with a thermometer, till a
temperature of 50 -60 is reached, and the effervescence has
ceased. Place the dish on a sheet of asbestos paper on a tripod,
in a hood with a good draught. Add 40 grams of powdered
potassium cyanide, and stir vigorously with the thermometer.
Warm only very gently till the reaction, which takes place with
considerable evolution of heat and spontaneous boiling of the
solution, is complete. Then raise the flame and evaporate rap-
idly, stirring constantly with the thermometer till a temperature
of 130 is reached. During this part of the operation keep the
window glass of the hood between the dish and the face, and
cover the hand with a towel or glove to protect it from the par-
ticles of the mixture which are thrown out. ' Remove the dish
from the flame, and continue to stir till the mass is cold.
Transfer at once to a 500 cc. flask as the mass is very hygro-
scopic. Connect the flask with an upright condenser (see 20,
p. 68). Add 20 cc. of alcohol and then, in small portions,
through the condenser, a cooled mixture of 80 cc. of alcohol
with 80 cc. of concentrated sulphuric acid. After each addi-
tion, mix the contents of the flask as thoroughly as possible by
shaking. When all of the mixture has been added, shake till
the whole is thoroughly mixed, and then heat on the water-bath
for an hour. Cool, add 150 cc. of cold water, and shake thor-
oughly. Filter on a Hirsch funnel or plate, and suck the liquid
through as completely as possible. Stop the pump, moisten the
salt with ether; after a minute or so draw this through, and
repeat twice. Transfer the contents of the filtering flask to a
separatory funnel and draw off the salt solution below. Add a
small amount of a strong solution of sodium carbonate to the
ethereal solution, and shake carefully with the funnel open
at the top to allow the carbon dioxide to escape. When enough
of the solution has been added to neutralize the free acid,
insert the stopper and shake more vigorously, holding the stop-
per firmly in place, and after each shaking turning the funnel
bottom-side up and opening the stop-cock to relieve the pres-
sure. Allow the two layers to separate as completely as pos-
138 ORGANIC CHEMISTRY
sible, draw off the aqueous solution below, allowing it to run
into the first acid solution. Transfer the ethereal solution of
the malonic ester to a distilling bulb. Distil off the ether on
a water-bath, us ; ng a condenser, then put in the mouth of the
bulb a rubber stopper bearing a tube drawn out below to a
fine capillary, which reaches nearly to the bottom of the bulb,
and attach a second bulb to the side tube (see Fig. 34, 171,
but omit the thermometer). Heat in the water-bath and re-
duce the pressure to 50 mm., or less, for fifteen minutes. This
method of drying substances which boil above 190 is usually
quicker and more satisfactory than the use of calcium chloride
or other drying agents. Malonic ester may also be dried with
advantage by allowing it to stand in a crystallizing dish in a
vacuum desiccator for twenty-four hours.
After drying, distil with a thermometer and condensing tube
(see i, p. 26). Very little passes over below 190, and that
boiling from I9O-2OO will be very nearly pure malonic ester,
If a very pure ester is desired, it may be distilled again, and only
the portion boiling within one degree of the true boiling-point
taken. Yield, 45 grams.
The sodium carbonate solution contains some of the acid ester.
If this solution is added to the first acid solution, the acid ester
separates with some ether. The ethereal solution may be sep-
arated, the ether evaporated at a gentle heat, and the residue
added to the contents of the flask, in which a second saponifi-
cation of the cyanacetate is to be effected. This will increase the
yield to 50 grams.
Malonic ester is a colorless liquid which boils at 198, and
has a specific gravity of 1.061 at 15. It is decomposed on heat-
ing to 150 with water, giving acetic ester, carbon dioxide, and
alcohol. (For the conduct of malonic ester toward sodium
ethylate and its use in syntheses, see p. in.)
If it is desired to prepare malonic acid, after adding the
potassium cyanide as directed above, continue to heat gently
for half an hour, then add 120 cc. of a strong solution of so-
dium hydroxide (3 cc. = i gram' NaOH), and continue to heat,
replacing the water which evaporates, as long as the evolution
ACIDS I3Q
of ammonia continues, usually about an hour. Add carefully
68 cc. of hydrochloric acid (4 cc. = I gram HC1), and a solu-
tion of 70 grams of calcium chloride. Filter, wash with cold
water, and dry at 100. The calcium malonate retains two
molecules of water. To obtain the free acid the salt is decom-
posed by warming with the calculated amount of a strong so-
lution of oxalic acid, filtering from the calcium oxalate, and
evaporating to crystallization. Malonic acid melts at 134 and
dissolves in about two-thirds of its weight of water at 16. At
140-! 50 it decomposes into carbon dioxide and acetic acid,
a reaction characteristic of acids having two carboxyls combined
with one carbon atom.
The calcium salt is almost insoluble in cold water.
The malonic ester prepared by the directions given contains
/CO.C.H,
some cyanacetic ester, CH 9 C 6 H 3 OH.
X C(X
If resorcinol is used in place of phenol, and zinc chloride is
used as a condensing agent, (half the weight of the phthalic
a'nhydride), the temperature being raised to 2OO-2ii till the
O
mass becomes solid, fluorescein, ,C - C 6 H , s
C H '\COOH
ACIDS 143
formed. By treating with bromine in an alcoholic solution, this
is converted into tetrabromfluorescem (eosin). Eosin and other
similar compounds, and also anthracene derivatives which are
obtained from these compounds by heating with concentrated
sulphuric acid (see above), are used as dyes.
Compounds of the fluorescein type are only formed when the
hydroxyl groups of the phenol are in the meta position and the
third meta position is also free.
Chapter VIII
DERIVATIVES OF ACIDS
The derivatives- of organic acids are of two classes: those
derivatives in which the carboxyl (CO 2 H) group is affected,
and those in which the rest of the acid is changed. To the
former class belong salts, chlorides, anhydrides, amides, and
esters ; to the latter, halogen derivatives, nitro derivatives, amino-
acids, hydroxy-acids, and, indeed, nearly or quite all classes
of derivatives which may be formed from hydrocarbons. Only
the first class of derivatives will be considered in this chapter.
The chlorides of acids are prepared by treatment of the acid,
or one of its salts, with phosphorus trichloride, phosphorus
pentachloride or phosphorus oxychloride. The trichloride is
usually used for the lower members of the fatty acid series, and
for cases where the boiling-point of the chloride is near that of
phosphorus oxychloride.
O O
// //
3RC - - OH + 2PC1 3 = 3 R _ C Cl + 3HC1 + P 2 O 3 .
For other cases, and especially when acids react with difficulty,
phosphorus pentachloride is used.
O O
// //
R C OH + PC1 5 = R C Cl + POC1 3 + HC1.
Phosphorus oxychloride is rarely used except with the salts
of acids.
O O
// //
2R C ONa + POC1 3 = 2R C Cl + NaPO 3 + NaCl.
The anhydrides of monobasic acids are usually prepared by
the action of the chloride of the acid on its sodium salt.
O O
// \
R _ COC1 + RCO.ONa = R C O C R + NaCl.
DERIVATIVES OF ACIDS 145
In some cases an excess of the alkaline salt is treated with
phosphorus oxychloride.
4 R __ CO.ONa + POC1 3 = NaPO 8 + 3NaCl +
2 R_CO O CO R.
Bibasic acids in which the two carboxyl groups are separated
by two carbon atoms, either in the aliphatic or aromatic series
(succinic and phthalic acids and their derivatives), readily form
inner anhydrides, in most cases by the action of heat alone and
at temperatures below 210. (Auwers: Ann., 285, 223.) The
formation of such anhydrides can be effected at lower tempera-
tures, and in most cases quantitatively by the use of acetyl
chloride, acetic anhydride, or phosphorus oxychloride.
/CO,H /OX
2R< + POC1 3 = 2R< >O + sHCl + HPO 3 .
X C0 2 H NCCX
Glutaric acid and its derivatives with open chains and, ap-
parently, the "cis" forms of cyclic derivatives, also form an-
hydrides by the same treatment, but isophthalic acid gives no
inner anhydride.
Amides may be prepared in many cases by heating ammo-
nium salts of acids.
O O
// //
RC ONH 4 = R - - C NH, + H 2 O.
Another method, which is applicable in almost all cases where
the resulting amide is difficulty soluble in water, consists in
treating the acid with phosphorus pentachloride to convert it
into chloride, and then adding the mixture of the chloride with
phosphorus oxychloride carefully to cold concentrated aqueous
ammonia, or ammonia gas may be passed into the mixture, diluted
with benzene, ether, or chloroform. In some cases it is best to dis-
til away the phosphorus oxychloride under diminished pressure
before adding the chloride of the acid to the ammonia. In
others the oxychloride may be decomposed by ice-water without
decomposing the chloride of the acid,
ro
146 ORGANIC CHEMISTRY
O O
// //
RC Cl + 2NH 3 = R C NH 2 + NH 4 C1.
Esters, on treatment with ammonia, are converted into amides :
O O
// //
R C OR' + NH 3 = R C NH 2 + R' OH.
This method is seldom used, except in cases where other
methods fail. (See Einhorn and Bull: Ann., 295, 207; Noyes :
Am. Chem. J., 20, 811.)
The preparation of amides from nitriles or cyanides has been
referred to on p. 108.
Acids which form inner anhydrides form also imides in which
the NH group takes the place of the oxygen atom which com-
pletes the ring in the case of the anhydride. These imides may
be prepared by heating the ammonium salt of the acid:
/CO - ONH 4 /CO V
R< = R< >NH + NH 3 -f H 2 O.
X CO ONH 4 X CCK
In some cases the ammonium salt of the half amide of the
acid gives better results. The conversion of an anhydride into
an imide by the action of ammonia, or ammonium carbonate,
probably depends on the intermediate formation of such a salt:
/C0\ /CO NH 2 /CO V
-
>O -f 2NH 3 == R< = R< >NH
CK X CO ONH 4 \CCK
-f NH 3 rf- H 2 0.
Closely related to the amides are anilides and similar com-
pounds, which may be considered either as amides having a
hydrogen atom of the NH 2 group replaced by a hydrocarbon
residue, or as an amine having a hydrogen atom of the amine
group replaced by an acid radical. Anilides and similar com-
pounds may frequently be prepared by simply heating the acid
with the amine, water being eliminated more easily than in the
case of the ammonium salts.
RCOOH -f R'NH 2 = R CO NHR' + H 2 O
A more general method consists in treating the amine with
DERIVATIVES OF ACIDS 147
the chloride or anhydride of the acid, either directly, or in the
presence of an aqueous solution of sodium hydroxide. ("Schot-
ten-Baumann reaction," see 65, p. 154'.)
Alkyl or aryl cyanides may also be considered as derivatives
of acids and as such they are called nit riles. From this point
of view they may be prepared by treating the amide of an acid
with phosphorus pentoxide :
R CONH 2 + P 2 O 5 = R CN + 2HPO 3 .
The preparation of cyanides from alkyl halides and in other
ways has already been considered, (p. 107).
Esters of strong acids may be prepared by bringing together
the acid and alcohol. The action is aided by heat. The reac-
tion is, however, a reversible one and proceeds only till an equilib-
rium is established between the amounts of ester, water, alco-
hol, and acid present. For equivalent weights of acid and alco-
hol, the per cent, of ester formed, when equilibrium is reached,
is characteristic of the acid and alcohol in question, and varies
greatly in different cases. Primary alcohols form esters more
quickly and in larger amount than secondary, and secondary
than tertiary. In a similar manner acids with a primary car-
boxyl (R CH 2 CO,H) form esters more quickly than those
with secondary carboxyl, and the latter more quickly than those
with a tertiary carboxyl. These facts may be used to determine
the structure of the alcohols and acids (Menschutkin, see third
edition of Beilstein I, 218 and 389. For a practical application
in determining the structure of an acid see Noyes : Am. Chem. J.,
18, 685).
The amount of an acid which will be converted into an ester
is increased by the use of a larger amount of the alcohol, in
accordance with the law of mass action, which applies to all re-
versible processes, that the increase of the amount of one of the
reacting substances increases the amount of product or product?
(in this case ester and water) which result from its action on
other substances present. It follows that an excess of the al-
cohol should be used when the acid is rare or expensive, and an
excess of the acid when the alcohol is valuable.
148 ORGANIC CHEMISTRY
In most cases esterification is very much hastened by the ad-
dition of hydrochloric or sulphuric acid to a mixture of an or-
ganic acid and alcohol. It was formerly supposed to be nec-
essary to saturate the mixture with dry hydrochloric acid gas,
but Emil Fischer has shown (Ber., 28, 3252), that a compara-
tively small amount of hydrochloric or sulphuric acid may fre-
quently be used with better advantage.
Esters may, in most cases, be readily prepared from the chlo-
rides of acids by treatment with an alcohol. (See Baeyer: Ann.,
245, 140.)
O O
// //
R C Cl + R' O H = RC OR' + HC1.
They may also be prepared by treating a silver salt of an acid
with an alkyl iodide,
O O
// //
R C OAg + R'l = R C OR' + Agl.
For methyl esters dimethyl sulphate and the sodium salt of
an acid may be used.
58. Preparation of an Acid Chloride. Acetyl chloride,
CH 3 .COC1. (Ethanoyl chloride.)
Literature Bechamp: Jsb. d. Chem., 1855, 504; 1856, 427; J. prakt.
Chem., 65, 495 ; Thorpe : J. Chem. Soc., 1880, 37> 186 ; Bothamley, Thomp-
son : Chem. News., 1890, 62, 191 ; Gerhardt : Ann., 87, 63.
100 grams acetic acid (glacial).
80 grams phosphorus trichloride.
Arrange a 300 cc. distilling bulb, condenser and receiver as
indicated in Fig. 33.
All of the apparatus must be absolutely dry, and the side
tube of the receiver should be connected with a tube which will
deliver the hydrochloric acid evolved immediately over the sur-
face of some water in a bottle. Place in the distilling bulb 100
grams (96 cc.) of glacial acetic acid, and add through the drop-
ping funnel 80 grams of phosphorus trichloride. Warm for a
short time, gently, till the evolution of hydrochloric acid nearly
DERIVATIVES OF ACIDS
149
ceases and the liquid separates in two layers. Then distil from
a water-bath as long as anything comes over. The distillate
usually contains some phosphorus trichloride. If a product en-
tirely free from phosphorus is required, add two or three grams
of powdered, dry, sodium acetate, allow to stand over night, and
distil again from the water-bath, collecting the portion boiling
at 5o-56. Yield 80 to 90 grams.
Acetyl chloride is a colorless liquid with a very disagreeable
odor. It boils at 50.9, and has a specific gravity of 1.1051 at
Fig. 33-
20. It decomposes rapidly with water or moist air and must
be kept in tightly closed, glass-stoppered, or sealed bottles.
Acetyl chloride reacts readily with almost all bodies containing
either an alcoholic hydroxyl, or an amine group. In both cases
a hydrogen atom of the group is replaced by the acetyl group,
Q 2 H 3 O. The resulting compounds are, in many cases, crys-
talline and difficultly soluble in water, and hence well adapted
for the characterization of substances of these two classes.
59. Preparation of an Anhydride of an Acid. Acetic anhy-
O O
// %
dride, CH S C O C -- CH 3 . (Ethanoic anhydride.)
Literature Gerhardt: Ann., (1852}, 82, 131; 87, 149.
60 grams dry sodium acetate.
50 grams acetyl chloride.
15O ORGANIC CHEMISTRY
Place in a dry, 200 cc. flask, 60 grams of freshly fused, dry,
powdered sodium acetate, and connect with an upright condenser.
Add, in small portions, through the condenser, 50 grams of
acetyl chloride, shaking vigorously after each addition. Warm
on a water-bath as long as any acetyl chloride condenses and runs
back. Then connect the flask with the condenser in the usual
manner by means of rubber stoppers and a bent tube, and distil
slowly with a free flame, holding the burner in the hand. Collect
the portions boiling at I3O-I42. Add to the distillate two
or three grams of dry sodium acetate and distil again. Yield
40 to 50 grams.
Acetic anhydride is a colorless liquid with an unpleasant odor.
It boils at 138, and has a specific gravity of 1.08 at 15.
When most compounds containing alcoholic or amine groups
acetic anhydride reacts, giving the same products as acetyl chlo-
ride. The reaction is usually less violent, and, of course, no
hydrochloric acid is formed. Since acetic anhydride does not
react very quickly with cold water, it may be used for the Schot-
ten-Baumann reaction (65 and 66, pp. 154, 155), while acetyl
chloride cannot.
60. Preparation of the Anhydride of a Bibasic Acid. Succinic
CH 2
anhydride,
Literature Gerhardt u. Chiozza: Ann v 87, 293; Anschtitz : Ber., 10,
1883; Ann., 226, 8; Volhard: Ibid, 242, 150; Auwers : Ibid, 285, 223.
20 grams succinic acid.
13 grams phosphorus oxychloride.
Place in a small flask 20 grams (2 mols.) of dry succinic acid.
Add 13 grams (i mol.) of phosphorus oxychloride. Connect
with an upright condenser, and warm gently on an asbestos
plate so long as hydrochloric acid escapes. To avoid the escape
of the acid into the room connect the top of the condenser with
a tube which will deliver the gas just above the surface of water
in a bottle. When acid ceases to escape, transfer to a 50 cc.
DERIVATIVES OF ACIDS 15 1
distilling bulb, connect with an air condensing tube, and distil.
When the drops coming over solidify easily, remove the condens-
ing tube and distil slowly into a small flask without any con-
denser. Crystallize the anhydride from chloroform. Yield al-
most quantitative.
Instead of phosphorus oxychloride, 12 grams of phosphorus
pentachloride may be used but, in that case, the mixture should
be warmed on the water-bath till it becomes liquid before plac-
ing it on the asbestos plate over the free flame.
Succinic anhydride crystallizes from chloroform or acetic
anhydride in needles, which melt at 119.6. It boils at 261.
It may also be crystallized from absolute alcohol, but on boiling
for some time with absolute alcohol it is converted into the
mono-ethyl ester of succhrc acid.
61. Preparation of an Ester Ethyl acetic ester, (Acetic ester)
O
//
CH 3 C OC 2 H 5 . (Ethyl Ester of Ethanoic Acid.)
Literature Geuther: Jsb. d. chem., 1863, 323; Frankland, Duppa: Ann..
138, 205; Markownikoff : Ber., 6, 1177; Pabst : Bull. soc. chim., 33 35O.
25 cc. alcohol.
25 cc. concentrated sulphuric acid.
200 cc. alcohol.
200 cc. glacial acetic acid.
Place in a 250 cc. distilling bulb 25 cc. of alcohol, and 25
cc. of concentrated sulphuric acid. Put in the mouth of the
bulb a stopper bearing a separatory funnel, the stem of which
reaches nearly to the bottom of the bulb, and a thermometer
which dips in the mixture. (See ethyl ether, p. 81.) Connect
with a condenser and heat carefully to I3O-I35. Run in
slowly a mixture of 200 cc. of glacial acetic acid and 200 cc.
of alcohol, regulating the flow and the flame so that the tem-
perature remains at about 135. Shake the distillate in a flask
with a concentrated sodium carbonate solution till it no longer re-
acts acid, separate the aqueous solution by means of a separatory
funnel, add a solution of 50 grams of calcium chloride in 50
152 ORGANIC CHEMISTRY
grams of water, shake, and separate again, to remove alcohol
which it contains. Dry the acetic ester by allowing it to stand
over night with a little fused calcium chloride, and fractionate.
The portion boiling at 72-78 is nearly pure. For use in
the preparation of acetoacetic ester it should be allowed to
stand a day with one-fifth of its weight of granular calcium
chloride and filtered. Yield 80-90 per cent, of the theory.
Acetic ester boils at 77, and has a specific gravity of 0.9239
o " ^ c;
at 5 , and of 0.8300 at 1_ . It dissolves in 17 parts of
4 4
water at 17.5, 28 parts of the ester dissolve one part of water
It is easily saponified by boiling with alkalies, and is slowly
saponified by merely standing with water.
62. Saponification of an Ester with Sodium Hydroxide and De-
tection of the Alcohol Formed.
Literature H. Meyer: Analyse und Konstitutionsermittelung organ-
ischer Verbindungen, p. 510; Nernst : Theoretical Chemistry, Translation
of the 4th German edition, p. 550.
2 grams acetic ester.
15 cc. sodium hydroxide (10 per cent).
Put 2 grams of acetic ester and 15 cc. of ten per cent,
sodium hydroxide in a small flask, connect with an upright
condenser and boil for 'fifteen minutes, cool, transfer to a 5c
cc. distilling bulb and distil over about 6 cc. Put the distillate
in a very small distilling bulb and distil about 3 cc. To the
distillate add dry potassium carbonate till the alcohol separate?
on top. Transfer the upper layer to a small distilling bulb
and determine the boiling-point, boiling it with a very small
flame and using as small a distilling bulb as possible. See pp. 26
and 269. .For the saponification of a fat see 48, p. 121. For
the saponification of a cyanide see 52 p. 133 and 140.
63. Preparation of an Ester of a Bibasic Acid. Ethyl succinic
CH 2 C0 2 C 2 H 5
ester, |
CH 2 CO 2 C 2 H 5
Literature Wegcr: Ann., 221, 89; Fehling: Ibid, 49> 186, 195; Perkin :
J. Chem. Soc., 45, SIS ( 7 ##4) ; Crum Brown, Walker: Ann.. 261, 115.
DERIVATIVES OF ACIDS 153
loo grams succinic acid.
170 cc. alcohol.
5 cc. concentrated sulphuric acid.
In a 300 cc. flask put 100 grams of succinic acid, 170 cc.
of alcohol and 5 cc. of concentrated sulphuric acid. Heat
for two hours on a water-bath with an upright condenser or
condensing tube. Cool, and pour into a large flask containing
25 grams of sodium bicarbonate and 150 of water. Shake
thoroughly, and separate the ester. Wash it once with a little
water, dry as directed for malonic ester (see p. 138), and frac-
tionate. Yield good.
Succinic ethyl ester boils at 2i7-2i8, and has a specific
gravity of 1.0475 at 2 5-5-
64. Preparation of an Ester by Means of Phosphorus Pentachlo-
ride and Alcohol. Benzoic ethyl ester, C 6 H 5 CO 2 C 2 H 5 .
Literature Baeyer: Ann., 245, 140; Liebig: Ibid, 65, 351; E. Fischer,
Speier: Ber., 28, 1150, 3255.
10 grams benzoic acid.
21 grams phosphorus pentachloride.
50 cc. alcohol.
Put in a small flask 10 grams benzoic acid, and 21 grams of
phosphorus pentachloride. Connect with a tube which will
deliver the hydrochloric acid evolved just above the surface of
water in a bottle. Warm on a water-bath till all is liquid. Cool
and pour carefully into 50 cc. of alcohol. Cool thoroughly, add
100 cc. of water and enough ether to bring the benzoic ester
to the surface. Separate, wash with a solution of sodium carbo-
nate to remove acid, dry the ethereal solution by allowing it to
stand for several hours with dry potassium carbonate, pour
off, or filter, and distil from a small distilling bulb.
Other methods of preparing benzoic ester are more suitable,
and this method is only given as an illustration of a method
which is quite generally applicable. The yield is almost quan-
titative, if care is used.
Benzoic ester boils at 211, and has a specific gravity of
1.0502 at 1 6.
154 ORGANIC CHEMISTRY
65. Preparation of the Benzoyl Derivative of a Phenol Schot-
O
//
ten Baumann Reaction. Phenyl benzoate, C 6 H 5 C O C 6 H 5 .
Literature Baumann: Ber., 19, 3218; Udranszky and Baumann: Ibid,
21, 2744; Hinsberg: Ibid, 23, 2962; Schotten : Ibid, 17* 2545.
Dissolve about one-half gram of phenol in 5 cc. of water,
add three-fourths gram of benzoyl chloride and a little caustic
soda, enough so. that the solution remains alkaline after warm-
ing and shaking till the odor of benzoyl chloride has disappear-
ed. On cooling and standing the phenyl benzoate solidifies,
and, after filtering off and washing, may be crystallized from
a little alcohol. It melts at 69.
This reaction, which is generally applicable to alcohols, phen-
ols, and to primary and secondary amines, and in which acetic
anhydride, sulphonechlorides and other similar compounds may
be used instead of benzoyl chloride, is especially useful in con-
verting liquid or easily soluble bodies into solid, difficulty solu-
ble derivatives for purposes of identification.
66. Preparation of the Ester of a Hydroxy Acid and of an
Acetyl Derivative. Di-acetyl tartaric ethyl ester,
C0 2 C 2 H 6
CH OC 2 H 3 O
CH - OC 2 H 3
C0 2 C 2 H 5 .
Literature. Landolt : Ann., 189, 324; Anschiitz : Ber., 18, 1397; Wislice-
nus: Ann., 129, 184; Perkin : A Supl., 5, 285; J. Chem. Soc., 51, 369
(1887); E. Fischer: Ber., 28, 3255.
25 grams tartaric acid.
1 20 cc. absolute alcohol.
i gram hydrochloric acid gas.
Put 25 grams of tartaric acid in a 200 cc. distilling bulb, add
1 20 cc. of absolute alcohol, and pass into the bulb about one
gram of hydrochloric acid gas. The gas may be generated in a
small flask from salt and concentrated sulphuric acid diluted
DERIVATIVES OF ACIDS 155
with one-fourth of its volume of water, or by dropping concen-
trated sulphuric acid into commercial hydrochloric acid, and
the amount can be determined by placing the bulb in a beaker
on one pan of a balance, which is sensitive to about one-tenth
gram. Close the side tube of the bulb with a bit of rubber tubing
and a glass rod, and place in the mouth of the bulb a stopper
and tube to act as an ,air condenser. Heat for 2 to 3 hours
on a water-bath, inclining the bulb in such. a manner that the
vapors which condense in the side tube will run back into the
bulb. Adjust a capillary tube and stopper, and a second bulb to
collect the distillate, as on p. 171 and distil the excess of alcohol
and the water formed under gradually diminishing pressure, and
tmally dry for fifteen minutes under as k.\v a pressure as can be
secured and with the bulb immersed in a boiling water-bath.
Add 80 cc. of absolute alcohol, and one gram of hydrochloric
acid, and heat as before with an air condenser for two hours.
By the removal of the water formed by the esterification, and a
second treatment with fresh alcohol a much more - complete
conversion can be secured. Distil the alcohol and water as be-
fore and then distil from an oil-bath or with the free flame
under as low a pressure as can be secured and with a thermom-
eter (see p. 171). The portion boiling a.t i6o-i8o under 30
mm. pressure will consist of nearly pure di-ethyl tartaric ester.
Yield 23-26 grams.
The ester boils at
280 under a pressure of 760 mm.
232 under a pressure of 197 mm.
162 under a pressure of 19 mm.
157 under a pressure of 11 mm.
It has a specific gravity of 1.2059 at 20
3 grams di-ethyl tartaric ester.
5 grams acetic anhydride.
30 cc. sodium hydroxide (10 per cent.).
Place in a small flask 3 grams of di-ethyl tartaric ester, add
five grams of acetic anhydride and then, in small portions, with
constant shaking, 30 cc. of a 10 per cent, solution of sodium
156 ORGANIC CHEMISTRY
hydroxide. As soon as the odor of the acetic anhydride has
disappeared, filter off the acetyl derivative, if it solidifies, wash
it with water and recrystallize it from alcohol, dissolving in
a very little hot alcohol, and adding water till the solution begins
to become turbid.
If the acetyl compound fails to solidify at first, it will usually
do so on standing in a cool place for a day or two. If somo of
the crystallized compound is at hand, the addition of a crystal
will be of service.
Di-acetyl tartaric ethyl ester melts at 67, and boils at 291-
292 under 727 mm., or at 229-23O under 100 mm.
Very considerable historical interest attaches to the substance,
because by means of it the structure of tartaric acid was first
clearly established.
67. Preparation of an Amide by Heating the Ammonium Salt
of an acid. Acetamide, CH 3 CONH 2 .
Literature. Letts : Ben, 5, 669; Hofmann : Ibid, 15, 9?8; v. Nencki,
Leppert: Ibid, 6, 903; J. Schultze: J. prakt. Chem., (1883), N, F., 27, 514
50 grams glacial acetic acid.
55 to 60 grams ammonium carbonate.
Warm 50 grams of acetic acid gently in a porcelain dish and
add powdered ammonium carbonate till a little of the mixture, on
dilution with water, shows an alkaline reaction with litmus.
Prepare two sealing tubes about 2 to 2.5 centimeters in internal
diameter, and with walls 2 to 3 mm. thick. In closing the ends
of the tubes, and also in sealing after they have been filled, the
glass must be so thoroughly softened as to sink together some-
what, and must not be drawn so rapidly as to become thin at
any point. Warm the sealing tubes gently over the flame, and
heat the ammonium acetate till it becomes liquid. Transfer it
to the tubes, using a thistle tube or funnel with a long stem so
that the tubes are not wet near the point where they are to be
sealed. The tubes, when sealed, should not be more than three-
fourths full. Seal the tubes carefully, and when cold put them in
a bomb oven and heat for five hours at 22O-23O. Cool. Open
the tubes and transfer the mixture to a distilling bulb and subject
DERIVATIVES OF ACIDS 157
it to fractional distillation, using an air condensing tube (see
p. 26). Collect the portion boiling at i8o-23O in a beaker.
Cool thoroughly, and spread on porous porcelain to remove
liquid impurities. The portion remaining will be nearly pure
acetamide. The pure compound may be obtained by crystalliz-
ation from benzene or chloroform. Yield about 25 grams.
Pure acetamide consists of colorless, odorless, rhombohedral
crystals, which-melt at 82. It boils at 222. It is easily solu-
ble in alcohol and in water, difficultly soluble in ether and ben-
zene.
Acetamide is easily saponified by alkalies. It is converted
into methylcyanide (acetonitrile) by warming for a short time
with phosphorus pentoxide and distilling. An aqueous solution
of acetamide dissolves mercuric oxide with the formation of the
compound, (CH 3 CONH) 2 Hg. The hydrogen of the amide
group may also be replaced by bromine or by other halogen
atoms. Acetamide forms unstable salts with hydrochloric acid
and with nitric acid.
68. Preparation of an Acyl Derivative of an Amine. Acet-
anilide, C 6 H 5 NH.C 2 H 3 O.
Literature Gerhardt : Ann., 87, 164; Williams: Ibid, 131, 288; Witt:
Dissertation, (Zurich, 1875), 12, Williams: J. Chem. Soc., 17, 106, (1864).
25 grams aniline.
35 grams glacial acetic acid.
Put in a 200 cc. flask 25 grams of aniline and 35 grams of
glacial acetic acid. Place in the mouth of the flask a stopper
bearing a tube one cm. in diameter and 50 cm. long. Heat on
a thin asbestos paper on a wire gauze, and adjust the flame so
that the vapors of the acetic acid condense about two-thirds of
the way up the tube. As water is formed during the reaction,
it will gradually escape from the top of the tube, and this hasten-
es the reaction. If the apparatus cannot be conveniently placed
in a hood, the top of the tube should be bent over, and a flask
placed under it to collect the dilute acid which escapes. After
boiling for 4 to 5 hours, pour carefully, with stirring, into 400
cc. of water, filter when cold, and recrystallize from hot water.
158 ORGANIC CHEMISTRY
dilute alcohol, or from benzene. Yield about 80 per cent, of the
theory.
Acetanilide (known in medicine as antifebrin) melts at 116,
and boils at 304. It dissolves in 189 parts of water at 6. It
is easily soluble in hot water, alcohol, ether, and benzene. It
may be saponified either by boiling with caustic potash or con-
centrated hydrochloric acid.
69. Preparation of an Amide from the Chloride of an Acid.
/NH 2
Urea, CO<( , Carbamide.
X NH 2
Literature. Wohler: Berz. Jsb., 12, 266 (1828}; Natanson : Ann., 98,
289; Basarow; J. prakt. Chem, [2], i, 283; Mixter: Am. Chem. J., 4
35; Millon: Ann. chim. phys., [2], 8, 235; Schmidt: Ber., 10, 191 ; Duggan :
Am. Chem. J., 4, 47; Schmidt: Z. anal. Chem., i, 242.
10 cc. solution of phosgene in toluene (20 per cent.).
15 cc. ammonia (0.96).
Put in a small flack 15 cc. of ammonia and add in three or four
portions, shaking and cooling after each addition, 10 cc. of a
twenty per cent, solution of carbonyl chloride, COC1 2 (phos-
gene), in toluene. The solution should now react alkaline. Pour
the mixture into a porcelain dish, and evaporate to dryness on
the water-bath. Put the residue into a dry test-tube, add about
10 cc. of alcohol, and boil. Cool, pour off through a filter, and
repeat the same treatment twice. Evaporate the alcoholic solu-
tion to dryness. The residue will now consist mainly of urea
with a little ammonium chloride. About one gram should be
obtained. Crystallize from a little amyl alcohol.
Urea crystallizes in long prisms or thick needles. It melts at
132. It is easily soluble in water. 100 parts of alcohol dissolve
5.06 parts at 19.5. From not too dilute aqueous solutions it is
/ 2
precipitated in the form of the nitrate, CO^ , on the
\NH 2 HNO 3
addition of nitric acid. The nitrate is very difficultly soluble in
/NH,
nitric acid, and is converted into nitrourea, CO\ , by
NHNO 2
DERIVATIVES OF ACIDS 159
cold concentrated sulphuric acid. (See p. 94). Urea forms dou-
ble compounds with many salts and metallic oxides, and, also,
compounds in which its hydrogen is replaced by metals. It is
decomposed by alkaline hypobromites with liberation of nitrogen,
a property used for its quantitative determination.
Concentrated solutions of alkalies decompose it on boiling,
with the formation of a carbonate and ammonia. Acids decom-
pose it more rapidly.
70. Preparation of an Amide by means of Phosphorus Penta-
chloride and Ammonia. Phenyl sulphonamide, C 6 H 5 SO 2 NH 2 .
Literature Mitscherlich : Ann. phys. (Pogg.), 3* 283, 631; Stenhouse:
Ann., 140* 284 ; Gattermann : Ber., 24, 2121 ; Michael, Adair : Ber., 10,
585; Gerhardt, Chancel : J., 1852, 434; v. Meyer, Ador : Ann., i59 n;
Limpricht: Ibid, 221, 206.
100 cc. fuming sulphuric acid (sp. gr. 1.87).
50 cc. benzene
350 cc. water.
50 grams acid sodium carbonate.
loo grams salt.
20 grams crude sodium benzene sulphonate.
20 grams phosphorus pentachloride.
70 cc. ammonia (sp. gr. 0.90).
To loo cc. of fuming sulphuric acid, containing 5 to 8 per
cent, of the anhydride (sp. gr. 1.87 at 15), in a 300 cc. flask,
add, in small portions, 50 cc. of benzene, shaking vigorously
after each addition and keeping the temperature below 50 by
occasional cooling. When the benzene has all dissolved, pour
slowly into 350 cc. of water, cool, and filter from any diphenyl
sulphone, (C 6 H 5 ) 2 SO 2 , which separates. Partly neutralize the
acid by adding, carefully, 50 grams of acid sodium carbonate
(baking soda), then add 100 grams of common salt, warm till
it dissolves, filter and cool, with stirring. As soon as the sodium
benzene sulphonate has separated completely, filter on a plate and
suck dry. Moisten with a saturated solution of salt and suck
dry again. Dry the salt on a plate of porous porcelain. Yield
J6O ORGANIC CHEMISTRY
40 to 50 grams of the salt. The salt can be crystallized from al-
cohol if desired, but is already pure enough for most purposes.
/Place in a 100 cc. flask 20 grams of phosphorus pentachloride
(weigh in the hood and avoid exposure to the air as far as pos-
sible), add 20 grams of crude sodium benzene sulphonate, dried
at 120, close the flask with a perforated rubber stopper bearing
a tube which will deliver the hydrochloric acid evolved just
above the surface of water in a bottle or flask. Warm on the
water-bath as Pong as hydrochloric acid is evolved. Cool. Pour
the contents of the flask, in small portions, into/yo cc. of am-
monia (0.90 sp. gr.) contained in a 200 cc. flask]"* cooling thor-
oughly after each addition. Filter, wash with cold water, and
crystallize from hot water or from dilute alcohol. Yield 12 to
15 grams.
If benzene sulphonechloride is desired, th^T liquid product ob-
tained by the action of the pentachloride on sodium benzene sul-
phonate may be poured in small portions into 200 cc. of cold
water, and shaken with the latter for some time to decompose
the phosphorus oxychloride, the sulphonechloride taken up with
ether, and after drying with calcium chloride and distilling off
the ether, distilled unc^er diminished pressure.
Benzene sujphonechloride melts at 145 and boils with decom-
position at 246. Under 10 mm. pressure it boils at 120. It
has a specific gravity of 1.378 at 23.
It may be used to distinguish the three classes of amines
(Hinsberg: Ber., 23, 2963). With primary amines it gives alkyl-
sulphonamides, C fi H 5 SO 2 NHR, which are soluble in alkalies, with
secondary amines it gives dialkyl-sulphonamides C 6 H 5 SO 2 NRR',
which are insoluble in alkalies, and with tertiary amines it does
not react. The compounds with primary and secondary amines
may usually be prepared by the Schotten-Baumann reaction.
Benzene sulphonamide crystallizes in needles from water, or
in leaflets from alcohol. Both melt at I47-I48. (Hybbeneth
gives 156.) It is easily soluble in alcohol and ether, difficultly
soluble in cold water. The hydrogen of the amide group can be
replaced by metals, hence the sulphonamides are soluble in alka-
lies, and some of them are quite soluble in a solution of sodium
DERIVATIVES OF ACIDS l6l
carbonate. It is probable that the amide dissolves in the "pseudo"
/ONa
form, C 6 H 5 SOCO, or || || \ COH
NH-C--NH/ Jj _ c-N^
Literature Uebig and Wohler : Ann., 26, 245 ; Wohler : Ann., 70, 229 ;
88, ioo ; Arppe: Ibid, 87, 237; Goesmann : Ann., 99, 374; Gibbs : Chem. Z.
1869, 729; Am. J. Sci., 48, 215 (1869) \ Ann. Supl., Bd., 7, 324; Horbac-
zewski: Ber., 15* 2678; Behrend u. Roosen : Ber., 21, 999; Ann., 251,
235, Formanek: Ber., 24, 3419; Zabelin : Ann. Supl. Bd., 2, 313; Fresen-
ius : Z. anal. Chem., 2, 456; Salkowski : Ibid, 16, 373; E. Fischer: Ber.,
X 7, 1785; 30, 549.
i liter urine.
25 cc. concentrated hydrochloric acid.
Add to one liter of urine 25 cc. of concentrated hydrochloric
acid and allow to stand in a cool place for two days. Decant
the liquid from the crystals of uric acid and wash them by de-
cantation. Transfer to a test-tube, dissolve in the smallest possi-
ble amount of 5 per cent, sodium hydroxide, add a drop of a
solution of potassium pyrochromate and boil, then add a little
bone-black, shake, and filter. Precipitate the uric acid with hy-
drochloric acid, allow to separate completely, filter, and wash.
In working with larger amounts of uric acid the amount of the
pyrochromate should be five per cent, of that of the uric acid,
and after the second precipitation the uric acid, which is slightly
yellow, should be warmed several times with strong hydrochloric
acid, till it is perfectly white. (Gibbs: Loc. cit.) *
The yield from one liter of urine will usually be one-half a
gram or less.
Uric acid, forms a white crystalline powder, which is almost
insoluble in water, alcohol, and ether. It dissolves in alkalies
with the formation of salts in which two atoms of hydrogen
are replaced by the metal. Carbon dioxide precipitates from
such solutions difficultly soluble acid salts, a property used in
the preparation of the acid from guano. It is precipitated from
its solutions by an ammoniacal solution of silver nitrate. If a
DERIVATIVES OF ACIDS 163
little uric acid is moistened with nitric acid, and the solution
evaporated on the water-bath, the residue dissolves in ammonia to
an onion-red solution, which becomes violet on adding sodium
hydroxide ("murexide reaction").
Nitric acid oxidizes uric acid to alloxan,
/NH CO X
CO/ >C(OH)., + 3 H.,0,
X NH CO/
and the latter is decomposed by alkalies into urea and dihydroxy-
X C0 2 H
/ OH
malonic acid (mesoxalic acid), C<^TJ
v \Jl~L
X C0 2 H
The structural formulas given above are based, in part, on
these reactions.
Chapter IX
HYDROXY AND KETONIC ACIDS
Hydroxy acids may be prepared by several of the methods
used for the preparation of alcohols, as for instance: by the
treatment of a halogen derivative of an acid with water or an
alkali, or with silver oxide and water; by the treatment of an
amino acid with nitrous acid ; or by the oxidation of an unsat-
urated acid with potassium permanganate, giving a dihydroxy
acid. (See pp. 64, 65.)
Ortho- and para-hydroxy acids may be prepared from phenols
by heating a sodium or potassium salt of a phenol with carbon
dioxide (Kolbe's Synthesis). It was formerly supposed that a
phenyl sodium carbonate is at first formed but Tijmstra has
shown (Ber., 38, 1375) that the reaction consists at first in the
direct addition of the phenolate to carbon dioxide :
/ONa
C 6 H 5 ONa + CO 2 C 6 H /
X C0 2 H
If the reaction is carried out in an autoclave under pressure
it may be made nearly complete, while at atmospheric pressure
the compound formed reacts with another molecule of the phenol-
ate and phenol distils away :
ONa /ONa
+ C 6 H 5 ONa.- C 6 H 4 <( f C 6 H 5 OH.
CO 2 H x CO 2 Na
With sodium phenolate. the carboxyl enters chiefly in the ortho
position, giving salicyclic acid, while with potassium phenolate
para-hydroxy benzoic acid is formed.
Cyanhydrines may be prepared by the addition of nascent hy-
drocyanic acid to an aldehyde or ketone. The cyanhydrine may
be saponified to an a-hydroxy acid.
OH
-f- HCN == R CH - CN.
HYDROXY AND KETONIC ACIDS 165
/OH ,
R CH/ 4- HC1 -h 2H,O R CH< -f- NH 4 C1.
X CN X C0 2 H
Under the influence of sodium ethylate some esters may be
condensed to form esters of ketonic acids, of which acetoacetic
ester and succinylosuccinnic ester may be considered types (see
p. 109).
When, a compound contains a methylene (CH 2 ) or methine
(CH) group which is combined with two carboxyl groups, as in
acetoacetic ester or malonic ester or between a carboxyl and a
cyanogen group, as in cyanacetic ester it will usually react with
sodium ethylate in the "enol" form giving a sodium salt which
will, in turn, add an alkyl group in such a manner as to practi-
cally replace the hydrogen of the methylene or methine group by
the allyl radical (see p. in). The decompositions of acetoacetic
ester and of malonic acid and their derivations have already been
considered (p. 112).
73. Preparation of a Hydroxy Acid by Treatment of the
Sodium Salt of a Phenol with Carbon Dioxide (Kolbe's Syn-
/C0 2 H (i)
thesis). Salicylic acid, C 6 H 4 / (0-hydroxybenzoic
X)H (2)
acid).
Literature Gerhardt : Ann., 45> 21; Kohler : Ber., 12, 246; Earth: Ann.,
J 54i 360; Hiibner: Ibid, 165, i ; Gerland : Ibid, 86, 147; Kolbe, Lautemann :
Ibid, ii5i 201; Kolbe: J. prakt. Chem., [2], 10, 93; Hentschel: Ibid,
[2], 27, 41-; Schmitt: Ibid, [2], 3*, 407; Reimer, Tiemann : Ber., 9, 423,
824; 10, 213; Tijmstra: Ibid, 38, 1375.
12.5 grams sodium hydroxide.
30 grams phenol.
20 cc. water.
Dissolve 12.5 grams of sodium hydroxide in 20 cc. of water
in a porcelain, or better, in a nickel dish. Add, in portions, 30
grams of crystallized phenol. Fasten the dish firmly by means
of a clamp and, with the burner in the hand and in constant
motion, heat and stir carefully till a thoroughly dry powder is ob-
1 66 ORGANIC CHEMISTRY
tained. Transfer this at once to a 100 cc. distilling bulb, or re-
tort, place the latter in an oil-bath and pass through it a current
of dry hydrogen, while the bath is heated to 140 for half an
hour.
The salt should be so dry that it does not sinter together
during this part of the process. Allow the oil-bath to cool to
110, and pass a current of dry carbon dioxide through the bulb
for one hour. Then allow the temperature to rise at the rate of
about 20 an hour till a temperature of 200 is reached, and
heat finally for an hour at that temperature, continuing a slow
current of carbon dioxide. The side tube of the distilling bulb
should be heated gently, once in a while, to melt the phenol
which distills over. Cool, rinse the phenol out of the side tube,
dissolve the residue in the distilling bulb in water, filter, if
necessary, and precipitate the salicylic acid from the filtrate with
concentrated hydrochloric acid. Recrystallize from water, us-
ing a little bone-black, if the acid is colored. Yield 5 to 10
grams.
The potassium phenolate reacts at 150 in the same manner as
the sodium salt, but at 220 it gives the parahydroxybenzoate
instead of the salicylate.
This synthesis is quite general in its application, and deriva-
tives of phenol react in a manner similar to phenol itself.
Salicylic acid crystallizes in white needles which melt at 156.
The solution gives an intense violet color with ferric chloride,
a reaction characteristic of all orthohydroxy acids of the benzene
series. Salicylic acid is often used in articles of food on account
of its antiseptic properties, and the reaction with ferric chloride
is made use of in its detection.
74. Preparation of an a -Hydroxy Acid from an Aldehyde,
through the Cyanhydrine. Mandelic acid, C 6 H 5 C CO 2 H (phen-
\H
ethylolic acid).
Literature Winckler: Ann., 18, 310; Spiegel: Ber., 14, 239; Engler,
Wohrle: Ibid, 20, 2202; Wallach : Ann., i93 38; Louguinine u. Naquet :
Ibid, i39, 299; Miiller: Ber., 4, 980.
HVDROXY A NIT KE)TONIC ACIDS l6/
20 grams benzaldehyde.
13 grams potassium cyanide.
15.3 cc. hydrochloric acid (sp. gr. 1.19).
Put into a small flask 13 grams (i mol.) of pure potassium
cyanide, and 20 grams (i mol.) of freshly distilled benzaldehyde.
Place the flask in ice-water, and drop in slowly from a burette
7 grams (i mol.) of hydrochloric acid. This will be 14.3 cc. of
an acid of sp. gr. 1.20, or 15.3 cc. of an acid of sp. gr. 1.19.
During the addition of the acid shake frequently, and allow the
mixture to stand for one hour after all has been added. Then
pour into 150 cc. of cold water. Separate the cyanhydrine from
the solution, and wash twice with water (see 51, p. 127). Trans-
fer the nitrile to a porcelain dish, add 50 cc. of concentrated hy-
drochloric acid, and evaporate on a sand bath till crystals begin
to separate on the upper surface of the liquid. Dissolve the
residue in about 100 cc. of warm water, filter from any oil which
remains, and extract the mandelic acid from the filtrate with
ether.
In extracting with ether, especially when, as in this case, the
substance to be extracted is easily soluble in water, the solution
should be as concentrated as possible. It is also an advantage, in
many cases, to add salt or ammonium sulphate to the solution
which is to be extracted. This lessens the solubility of the ether
in the solution and also of the water in the ether. In extracting,
put the solution to be extracted into a separatory funnel, which
should be chosen of such size as to be nearly filled. Add, ac-
cording to the ease with which the substance is extracted from
the solution and according to the volume of the latter, 10-50 cc.
of ether. When a substance is easily extracted, use but little
ethei ; if extracted with difficulty, a larger amount; and the ex-
traction must, in such a case, be many times repeated. These
rules follow from the law for the division of a substance be-
tween two immiscible solvents, which is, that the amounts re-
tained in a unit volume of each have a fixed ratio, independent-
ly of the volume of each. The ratio is called the partition
coefficient, and in the present case expresses the amount of sub-
1 68 ORGANIC CHEMISTRY
stance contained in 100 cc. of the aqueous solution divided by
the amount contained in 100 cc. of the ethereal solution.
Expressed mathematically, let
.r = amount of substance present.
x^ amount of substance retained by the water.
,r x^ = amount of substance retained by the ether.
k division-coefficient.
/ = amount of water.
m = amount of ether.
if a stream
of cold water is kept running over the receiving bulb, answers
every purpose. A good "Bunsen" pump which will reduce the
pressure quickly to 30 mm. or less, when the water is cold, is,
of course, required. The author has found that of E. C. Chap-
man, large size, the most satisfactory.
For substances of very high boiling-point or which decompose
easily a mechanical pump (Geryk's) which will reduce the pres-
7*0
700
-600
-300
200
/SO
IOO
- SO
Fig. 37- A
sure to i mm. or less is of very great advantage, as a further de-
crease in boiling-point of about 100 may be obtained in this way.
It is very convenient to have a manometer attached in such a
manner that the pressure can always be known whenever the
pump is used. That shown in Fig. 37 has been in use in the
author's laboratory for some years, and has the advantage over
the usual forms that the whole scale, from no pressure to that
of the atmosphere, occupies a space of only about 18-20 cm.,
and further that the air in the closed end above the mercury
174 ORGANIC CHEMISTRY
acts as a cushion and there is no danger of breakage when the
pressure is suddenly released. It is an advantage to have a
portion of the bend at A, of capillary tubing I mm. or less in
diameter.
The manometer is calibrated after it is put in position by com-
parison with the manometer of the usual form for low pressures,
both being connected with the same receptacle, which is exhausted
by the pump. For higher pressures it is calibrated by connecting
with a small tube standing perpendicularly in a dish of mercury,
subtracting the height of mercury in the tube from the height of
the barometer for the day.
Acetoacetic ester is a colorless liquid with an unpleasant odor.
It boils at 181, and has a specific gravity of 1.030 at 15.
Under diminished pressure it boils :
Under 12.5 mm. at 71*.
18.0 " " 79.
" 29.0 " " 88.
" 59-0 " " 97.
" 80.0 " " 100.
It is slightly soluble in water and is volatile with water vapor.
It gives a 'crystalline compound with sodium bisulphite, which
may be used as a means of purification. It gives with ferric
chloride, in aqueous solutions, a violet color characteristic of
ortho hydroxy derivatives of benzoic acid, and of other com-
pounds of similar structure. It is soluble in cold dilute alkalies
without decomposition, but on warming with alcoholic potash
it is decomposed, chiefly with formation of two molecules of
acetic acid and alcohol (acid decomposition). Boiling it with
dilute acids or alkalies decomposes it mainly with the formation
of acetone, carbon dioxide, and alcohol (ketonic decomposition).
For the use of acetoacetic ester in syntheses, see p. in.
On heating by itself, it decomposes with the formation of
dehydracetic acid, C 8 H 8 O 4 . This can be recovered from the
residues after distilling off the acetoacetic ester, by boiling them
with sodium carbonate and bone-black and crystallizing the so-
dium salt, after filtration. The latter is then decomposed with
HYDROXY AND KETONIC ACIDS IJ5
dilute sulphuric acid. The acid crystallizes in needles which
melt at 109. (Feist: Ann., 257, 253.)
By condensation of acetoacetic ester with aldehyde ammonia,
a pyridine derivative is formed, with aniline a chinoline deriva-
tive, with phenyl hydrazine a pyrazolone compound, and with
amidines pyrimidine compounds.
76. Condensation of Acetoacetic Ester with Itself. Diacetyl
CH 3 CO CH - C0 2 C 2 H 5
succinic ester,
CH 3 CO CH CO 2 C 2 H 5
Literature Rugheimer : Ber., 7, 892; Harrow: Ann., 201, 144; Nef :
Ibid, 266, 88; Knorr: Ber., 22, 170, 2100; Paal : Ibid, 18, 58, 2251.
150 cc. dry ether.
4 grams sodium.
20 grams acetoacetic ester.
20 grams iodine.
100 cc. ether.
Prepare some pure, dry ether as follows r 1 Fill a half liter
Ladenburg distilling bulb (see 75, p. 172) one-fourth full with
granular calcium chloride. Place in the bulb an inverted test-
tube of such size and length as to reach just to the bottom of
the neck and nearly close it, when resting on the bottom of the
bulb. Fill the neck nearly to the side tube with granular calcium
chloride, and then fill the bulb nearly to the neck with ordinary
ether. Stopper the bulb and allow it to stand over night. Then
distil on a water-bath, using a thermometer, and collecting the
ether in a dry bottle. Change the receiver as soon as the ther-
mometer rises 0.2 above the boiling-point of pure ether. The
ether dried in this way will answer for this preparation. For
a perfectly anhydrous ether some sodium wire must be pressed
into it, and the ether distilled after standing for a day. See,
however, pp. 82 and 74.
Ether should be kept in bottles with a smooth neck, and closed
with a tightly fitting cork, not with a glass or rubber stopf er.
The stock of ether should be kept, as far as possible, in bottles
; Method suggested by Dr. H. H. Ballard.
176 ORGANIC CHEMISTRY
which are filled full, as the loss is chiefly due to the expansion
and contraction of the air above the ether, which always carries
with it some of the vapor. The same is true of other volatile
liquids.
Place in a 300 cc. flask about 150 cc. of dry ether, weigh
carefully, and press into the flask about four grams of sodium
wire, taking care, of course, that there is no appreciable loss
of ether by evaporation. Weigh again, connect with an upright
condenser, and for each gram of sodium add five grams of
acetoacetic ester. Shake occasionally till the sodium is all dis-
solved, which will take from one to two hours. When an evo-
lution of hydrogen is no longer observed, after shaking, add in
small portions with shaking, a solution of about 20 grams of
finely powdered iodine in dry ether. Continue the addition only
so long as the color of the iodine disappears immediately after
each addition. Filter from the sodium iodide, distil the ether,
and crystallize the residue of diacetylsuccinic ester from glacial
acetic acid.
Diacetylsuccinic ester crystallizes in needles, or in monoclinic
plates, which melt at 88.
If saponified by strong caustic soda at ordinary temperatures,
the free acid can be obtained. If saponified by a 3 per cent,
solution of caustic soda, in exactly equivalent amounts, however,
acetonylacetone, alcohol, and carbon dioxide are formed.
77. Synthesis of an Acid by Condensation of Acetoacetic Ester
with a Halogen Compound. Hydrocinnamic acid,
C 6 H 5 CH 12 CH 2 C0 2 H,
( Phen-3-propanoic acid ) .*
Literature. Alexejew, Erlenmeyer: Ann., 121, 375; 137, 327; Gabriel,
Zimmermann : Ber., i3 1680; Fittig, Kiesow : Ann., 156, 249; Sesemann :
Ber., 6, 1086; 10, 758; Conrad, Hodgkinson : Ann., 193* 300; Conrad: Ibid,
204, 136; Conrad, Bischoff: Ibid, 204, 180; Fittig, Christ: Ibid, 268, 122;
For benzyl acetone, Ehrlich : Ibid, 187, n ; Jackson: Ber., 14, 890; Harries,
Eschnbach: Ibid, 29, 383.
1 This acid is called, in the Third Edition of Beilstein, phenathylsaure, but that name
does not agree with the principles of nomenclature proposed by the Geneva Congress
and Beilstein uses the same name elsewhere for a-toluic acid,
HYDROXY AND ^KETONIC ACIDS I7/
2.3 grams sodium.
35 cc. absolute alcohol.
13 grams acetoacetic ester.
12.6 grams benzyl chloride.
15 grams (about) benzyl acetoacetic ester.
30 cc. alcohol.
10 grams sodium hydroxide.
30 cc. water.
40 cc. hydrochloric acid (sp. gr. i.n).
Put 2.3 grams (i mol.) of sodium in a 100 cc. flask. Add
35 cc. of absolute alcohol, connect with an upright condenser,
and heat on a water-bath till the sodium is dissolved. Cool, add
13 grams (i mol.) of acetoacetic ester, which on shaking will
cause the sodium ethylate, which has separated, to dissolve. Add
12.6 grams (i mol.) of benzyl chloride, and heat on the water-
bath with an upright condenser for two hours. The solution
should now react neutral when a piece of dry reddened litmus
paper -is dipped in it and afterwards moistened. Cool, fitter
on a dry filter with the pump, and wash twice with a little al-
cohol. Distil the solution under ordinary pressure till the ther-
mometer reaches 110, and then under diminished pressure, lin-
ing an oil- or metal-bath. The Claisen distilling bulb may be used
with advantage (see 75, p. 172). The portion boiling at 160-
170 under a pressure of 12 mm., or i8o-i9O under a pressure
of TOO mm., will be nearly pure benzyl acetoacetic ester.
/COCH,
C 6 H. CH 2 CH<
X CO,C 2 H 5
A small portion, which boils at 70 higher, consists of dibenzyl
acetoacetic ester; 12-15 grams of the monobenzyl acetoacetic
ester should be obtained.
Put the benzyl acetoacetic ester in a 200 cc. flask, add 30 cc.
of alcohol, and 10 grams of sodium hydroxide dissolved in 30 cc.
of water. Boil with an upright condenser for an hour. Cool,
dilute with about 50 cc. of water, and extract twice with 10-20
178 ORGANIC CHEMISTRY
cc. of ether. Distil off the ether, dry the ketone which remains
in vacua over sulphuric acid, and distil ; or the ethereal solution
may be dried with ignited potassium carbonate before the ether
is distilled away.
Evaporate the alkaline solution to about 20 cc. and add 40 cc.
of hydrochloric acid (sp. gr. i.n). The hydrocinnamic acid
usually separates as an oil, at first, but will solidify on stand-
ing in a cool place for some time. Filter, and recrystallize from
hot water, reserving a very small crystal to cause the solidifica-
tion of the acid, in case it separates again as an oil.
The yield of the ketone and of the acid is about 3 grams each,
but better yields may be obtained by working with larger quan-
tities.
Benzyl acetone (i, 3-butylonephen C 6 H 5 CH, 2 CH 2 COCH 3 ) is a
liquid which boils at 235-236, and has a specific gravity of
0.989 at .
Hydrocinnamic acid crystallizes in long colorless needles, which
melt at 49. It boils at 280. It is easily soluble in boiling
water, and in alcohol and ether. It is volatile in water vapor.
It dissolves in 168 parts of water at 20.
78. Preparation of a Pyrazolone Derivative . Antipyrine,
CO N CH 3 i-Phenyl-2,3-dimethyl-pyrazolone.
I I
CH = C CH 3
Literature Knorr: Ber., 16, 2597; 17, 549, 2037; 28, 706; Ann., 238,
137; 2 79, 188; 293, i; Marckwald: Ibid, 286, 350; Nef : Ibid, 266, 131;
28 7 353; Bender: Ber., 20, 2747; Patents, Knorr: Ibid, *7> R, 149:
Meister, Lucius, and Briining: Ibid, 18, R, 725; 20, R, 609; 27, R, 282,
13 grams acetoacetic ester.
10 grams phenyl hydrazine.
10 grams i-phenyl-3-methylpyrazolone.
10 grams methyl iodide.
10 grams methyl alcohol.
HYDROXY AND ^KETONIC ACIDS 1/9
Put in a flask 13 grams of acetoacetic ester, add 10 grams of
phenyl hydrazine, and heat on the water-bath for two hours, or
till a drop of the mixture becomes perfectly solid on treating with
a little ether on a watch-glass. Pour the warm mass, with stir-
ring, into a small amount of ether, filter, wash with ether, and
dry.
The acetoacetic ester and phenyl hydrazine condense at first
with the formation of a hydrazide,
c \
C NH - NH C 6 H 5 ,
I!
C 2 H 5 C0 2 CH
and this, on heating, condenses, with loss of alcohol, to i -phenyl.
N
s\
3-methylpyrazolone, CO NH. In working with larger
I I
HC --= C CH 3
amounts it may be desirable to separate the water formed by the
first condensation as Knorr suggests, but the directions given
are satisfactory for small amounts. The phenylmethylpyrazolone
melts at 127, is almost insoluble in cold water, ether and ligrom,
more easily soluble in hot water, and very easily soluble in
alcohol. It dissolves both in acids and alkalies.
Put in a thick walled tube 10 grams of the phenylpyrazolone,
10 grams of methyl iodide, and 10 grams of methyl alcohol. Seal
carefully, (see p. 156), and heat in a bomb oven, or in an iron
tube (to guard against explosion) in a water-bath for two to
three hours. Cool, open the capillary by softening in a flame, cut
off the end, transfer the contents of the tube to a beaker, add a
small amount of a solution of sulphur dioxide, and some water,
boil to expel the alcohol, cool, add sodium hydroxide in slight
excess, and extract several times with a small amount of chloro-
form. Distil off the chloroform, and crystallize the antipyrine
ISO ORGANIC CHEMISTRY
from toluene. The yields are nearly quantitative, except for
the loss in manipulations.
Antipyrine crystallizes in leaflets, which melt at 116. It is
easily soluble in water, alcohol, benzene, and chloroform, diffi-
cultly soluble in ether and ligroin. The aqueous solution is
colored red by ferric chloride. Dilute solutions give a bluish
green color with nitrous acid.
79. Succinylosuccinic Ester.
C 2 H 6 O CO C = C(OH; CH,
CH 2 C(OH) == C CO O C 2 H 5 .
Literature Fehling: Ann., 49, 186; Herrmann: Ibid, 211, 306; Duis-
berg: Ber., 16, 133; Wedel : Ann., 219, 94; Baeyer: Ber., 19, 432; Mewes :
Ann., 245, 74; Baeyer u. Noyes : Ber., 22, 2168; Pinner: Ibid, 22, 2623;
Piutti: Gas. chim. ital., 22, 167.
50 grams succinic ester.
13.5 grams sodium.
2 cc. absolute alcohol.
Place in a 100 cc. round-bottomed flask 50 grams of succinic
ester (see p. 152) and 2 cc. of absolute alcohol. Press into the
flask 13.5 grams of sodium in the form of wire. (In such
cases it is desirable to know how much sodium will be left in
the press when the piston is forced to the bottom and allowance
should be made for this. The press must be cleaned with alcohol
and dried immediately after use. Instead of sodium wire finely
divided sodium prepared as directed on p. 170 may be used.)
During the addition of the sodium have a dish of cold water at
hand, and cool the flask by immersion in this, if the reaction
becomes violent. The flask should always be allowed to grow
warm, but should not become so hot as to melt the sodium.
When the sodium has all been added, and the reaction has pro-
gressed far enough so that the mixture no longer tends to grow
hot, connect the flask with an upright condenser and heat on a
water-bath for two hours. Stopper the flask and allow it to cool.
The mixture can be left at this po'nt over night without harm,
perhaps with advantage. The yield can be increased by longer
heating or longer standing, but the time taken is usually worth
HYDROXY AND KETONIC ACIDS l8l
more than the material saved. The contents of the flask -should,
at the end of the time, be converted into a dry, solid mass.
Put into a 500 cc. beaker 200 cc. of water and 150 cc. of dilute
sulphuric acid (25 per cent., sp. gr. 1.18). Set the beaker
in a large dish of cold water, and conduct to the surface of the
acid a slow current of carbon dioxide, which will prevent the
particles of unchanged sodium from taking fire as they dissolve
in the acid. Add the material from the flask to the acid in small
portions with vigorous stirring. It is frequently necessary to
break the flask to get the sodium salt, but the latter should not be
exposed to the air long before it is thrown into the acid.
The crude succinylosuccinic ester which separates is filtered off
on a plate, and washed with cold water. The crude ester, after
sucking as dry as possible, is then crystallized from hot alcohol.
For this purpose put in a 500 cc. flask about 300 cc. of alcohol
and add the ester only in such quantity that it dissolves quite
readily on boiling the alcohol on a water-bath. Filter hot and
very quickly on a plate, transfer the filtrate to a clean flask and
cool rapidly under the tap till the ester has crystallized. Filter
on another plate with a clean filter. Transfer the filtrate to the
first flask, add more of the ester, boil, filter, crystallize and collect
the crystals on top of the first lot. Repeat till all of the ester
has been crystallized, then wash the crystals once with pure alco-
hol and repeatedly with dilute alcohol.
Succinylosuccinic ester forms yellowish or greenish crystals
which melt at 127. It is almost insoluble in cold water, slightly
soluble in hot water, and difficultly soluble in cold alcohol. The
pure alcoholic solution has a beautiful blue fluorescence, and is
colored onion-red by ferric chloride. The ester dissolves in dilute
caustic soda, and is saponified with formation of the products of
both acid and ketonic decomposition by allowing the solution to
stand (Herrmann: Ann., 211, 322). A clean ketonic decom-
position with the formation of diketohexamethylene (cyclohex-
anedione 1.4) can be obtained by boiling with dilute sulphuric
acid. (Baeyer: Ann., 278, 91.)
By suspending in carbon disulphide and treating with the cal-
1 82 ORGANIC CHEMISTRY
culated' amount of bromine, it is converted quantitatively into
dihydroxyterephthalic ester.
80. Preparation of Ethyl Dihydroxymalonate and Ethyl Oxo-
malonate. (Ethyl ester of mesoxalic acid),
H O C0 2 C 2 H 5 C0 2 C 2 H 6
C and CO
/\ \
H O CO 2 C 2 H 5 CO 2 C 2 H 5
Literature Curtiss: Am. Chem. J., 35, 477; Curtiss and Spencer: J.
Am. Chem. Soc., 3 1 , 1054; Conrad, Bruckner: Ber., 24, 3000; Anschiitz,
Parlato : Ber., 25, 3615 ; Color of organic compounds, Curtiss : J. Am.
Chem. Soc., 3 2 , 795.
35 grams malonic ester.
35 grams oxides of nitrogen (NO and NO 2 ).
Put 35 grams of malonic ester (see p. 136) in a 100 cc. flask
and cool it to 13 with ice and salt or ice and commer-
cial hydrochloric acid. Pass into the weighed flask the oxides
of nitrogen prepared by dropping nitric acid (sp. gr. 1.42)
slowly upon 100 grams of arsenic trioxide while the mixture is
gently warmed. Pass the 'gases .through an empty flask or
wash bottle to condense moisture. Continue the passage of the
gas till the flask gains 35 grams in weight. Pack the flask in the
freezing mixture and allow it to stand over night, closing it with
a cork stopper bearing a tube closed with a Bunsen valve. 1 Then
allow the ice to melt and the mixture to come to room tempera-
ture, allowing it to stand for 24 hours longer. Note the loss in
weight. The color should now be dark green. Aspirate or blow
air through the liquid for 10-15 minutes to remove the excess
of oxides of nitrogen. Distil the residue under diminished pres-
sure, using a Raikoff receiver, (Chem. Ztg., 1888, 693), col-
lecting the distillate in three portions, the first containing water,
acetic acid and ester, the second, colorless dihydroxy malonic
ester and the third, to be collected when the distillate becomes
green, oxomalonic ester,
1 A piece of soft rubber tubing closed at the end with a glass rod and having two
short, longitudinal slits cut in its walls.
KYDROXY AND ATONIC ACIDS 183
To obtain the dihydroxymalonic ester from the green oxo-
malonic ester allow it to stand in the air for some hours with
occasional stirring. Water will be absorbed and the substance
will pass over into the colorless, crystalline hydroxy compound.
When the transformation appears to be complete filter on a plate
(p. 120) and suck as dry as possible. Stop the pump, moisten
the crystals with a little carbon disulphide and suck off again.
Repeat twice and then recrystallize from a mixture of equal
parts of ligro'in and benzene. Dihydroxymalonic ester crystal-
lizes in colorless plates which melt at 57. Yield 28 to 30
grams.
The anhydrous keto ester may be prepared by mixing the di-
hydroxy compound with twice its weight of phosphorus pent-
oxide (about 3 mols.) in a large distilling bulb and distilling
under diminished pressure after standing for twenty-four hours.
It boils at 115 under a pressure of 29 mm.
Dihydroxymalonic ester furnishes an illustration of the fact
that when a carbon atom is combined with one or two negative
groups it may retain two hydroxyl groups in combination. 1 To
show the dissociation of the compound put 0.25 gram in a test-
tube and warm very gently till it melts. Xotice that the liquid is
colorless. Raise the temperature to 9O-ioo. As the com-
pound dissociates and the water distils to the upper part of the
tube the thick oil which remains gradually becomes greenish in
color, the three carbonyl groups acting as a chromophore group.
The saturation of the central carbonyl group by the addition of
water, hydrochloric acid or other compounds destroys the chromo-
phore grouping. Cork the tube and allow it to stand and notice
the gradual recombination of the oxomalonic ester and water to
form the crystalline, colorless dihydroxy compound.
1 Another illustration is chloral hydrate. In crystallized oxalic acid three hydroxyl
groups are probably combined with a single carbon atom.
Chapter X
CARBOHYDRATES
The most important carbohydrates are sucrose,' maltose, lac-
tose, glucose and fructose, of the sugars, and dextrin, starch
and cellulose of the more complex compounds of' the group.
Sucrose or cane sugar is prepared from the juice of the sugar
cane, the sugar-beet or from the sap of the maple. It crys-
tallizes well from water and from alcohol and is easily obtained
in a high dgree of purity. Lactose, or milk-sugar is obtained
from the whey which remains after separating casein from milk
in the manufacture of cheese. Maltose is formed, together with
dextrin, by the action of the enzyme, diastase, of. malt, on starch.
Glucose is prepared, commercially, by the hydrolysis of starch
with dilute acids and crystallized rf-glucose is now an article of
commerce. In the laboratory it is more easily obtained from the
mixture of ^/-glucose and d'-fructose obtained by the hydrolysis
of sucrose. (Soxhlet: J. prakt. Chem. [2], 21, 244; Miiller: Ibid.
[2], 26, 83; Otto: Ibid, [2], 26, 91.) 181 ; 206, 207 ; Conrad: Ber., n, 2178;
Wolff: Ann':, 208, 105; Kent and Tollens : Ibid, 227, 229; Conrad
and Guthzeit: Ber., 18, 442; 19, 2572; Neugebauer: Ann., 227, 99; Risch-
bieth: Ber., 20, 1773; Wehmer and Tollens: Ann., 243, 314; Seissl : Ibid,
2 49, 275; Fittig: Ber., 29* 2583.
100 grams sugar.
400 cc. water
too cc. concentrated hydrochloric acid.
, Put in a 750 cc. flask 100 grams of cane-sugar, 400 cc. of
water, and 100 cc. of concentrated hydrochloric acid. Close the
flask with a tube containing water as in the preparation of cam-
phoric acid (see p. 122). Heat on a water-bath for 20 hours
Filter on a plate, boil the residue of humus with 100 cc. of
water and filter. To the combined filtrates add a solution of 35
grams of sodium hydroxide, and evaporate to about 100 cc.
Filter again, if necessary, and extract four or five times with
50-75 cc. of ether, distilling the ethereal extract and using the
same ether each time. For such cases it is convenient to put a
dropping funnel through the stopper of the distilling bulb so
that the ether may be introduced continuously and without re-
moving the bulb from the water-bath. A funnel should be placed
in the mouth of the dropping funnel to facilitate the pouring
CARBOHYDRATES 193
of the ether, and care must always be taken to avoid ignition of
the latter.
After distilling off the ether, transfer the residue to a smaller
distilling bulb, and distil under diminished pressure, raising the
temperature of the oil or air-bath slowly. Collect the portion
boiling at i4O-i6o under 15 mm., or at i6o-i8o under 80-100
mm. Put this portion in a wide-mouthed, tightly stoppered bot-
tle and allow to stand at o for some time, till it has solidified
as far as possible. Pour off the liquid part, warm the residue
gently till it melts, and allow it tc crystallize slowly at ordinary
temperatures. After draining off the liquid part the solid acid
will be nearly pure. Yield 10-15 grams.
The reactions which take place are, first, the inversion of the
cane-sugar to levulose and glucose, and then the decomposition of
these into levulinic and formic acids and water.
CH 2 OH
CHOH
CHOH
CHOH CH.COCH.CH.CO.H + HCO 2 H + H,O.
CHOH
CHO
Levulinic acid melts at 33, and boils with slight decomposi-
tion at 245-246 under 760 'mm. pressure, or I48-I49 under
15 mm. If heated for some time a"t its boiling-point, it is con-
verted into a mixture of a- and ^-angelica lactones,
CH 3 C = CH CH 2 CO and CH,= C CH.,CH 2 CO.
i i I
O H O 1
It gives with phenylhydrazine a crystalline hydrazone, and is
reduced to y-hydroxyvaleric acid by sodium amalgam. On acidi-
fying a solution of the sodium salt of this acid, valerolactone
separates.
Chapter XI
HALOGEN COMPOUNDS
Chlorine and bromine derivatives of the hydrocarbons may be
obtained by the direct action of the elements on the hydro-
carbons. In the fatty acid series of hydrocarbons this method of
preparation is of scarcely more than theoretical interest, partly
because the hydrocarbons are difficult to obtain in pure condition,
and partly because both primary and secondary halogen alkyls are
formed, and frequently di- and tri-substitution products as well.
If a complete replacement of the hydrogen by chlorine or
bromine is desired, the addition of a small amount of iodine great-
ly facilitates the action. (For the? chlorination of butane from
petroleum, see Mabery: Am. Chem. J., 19, 247.)
In the aromatic series direct replacement of hydrogen by
chlorine or bromine takes place easily, and pure products are
readily obtained. In this series, also, the presence of some sub-
stances greatly facilitates the reaction, the compounds most fre-
quently used for the purpose being ferric chloride or bromide.
The action of chlorine or bromine on aromatic hydrocarbons in
the cold and dark, but with, the addition of ferric chloride or
bromide, (or some powdered iron), causes a substitution of the.
hydrogen in the nucleus, anfl usually in the para or ortho posi-
tion with reference to the side chain. In the sunlight, or with the
boiling hydrocarbon, the substitution takes place in the side chain.
(Beilstein and Geitner: Ann., 139, 331; Jackson: Am. Chem. J.,
i,94: 2, i.)
The monohalogen derivatives of saturated hydrocarbons are
usually most easily obtained from the corresponding alcohols
by treatment with phosphorus trichloride, tribromide (or red
phosphorus and bromine), or pentaiodide,
3ROH + PBr 3 = 3RBr + H,PO 3 .
5ROH + 5! + P = sRI + H 3 PO 4 + H 2 O:
Dihalogen substitution products are often obtained from hy-
HALOGEN COMPOUNDS IQ5
drocarbons of the ethylene series by direct addition, giving com-
pounds in which the halogen atoms are combined with adjacent
carbon atoms. They may also be obtained from ketones or
aldehydes by treatment with phosphorus pentachloride or penta-
bromide, giving compounds in which the halogen atoms are com-
bined with the same carbon atom.
R \ R \
> CO + PC1 5 = > CC1, 4 POC1 3 .
R/ R/
Monohalogen derivatives of the ethylene series may be pre-
pared by treating di-halogen derivatives of the marsh gas series
with alcoholic potash or soda.
C M H 2n Br 2 + KOH = aH^Br -j- KBr -f H 2 O.
In the aromatic series halogen derivatives are often prepared
from the amines by passing through the diazonium compounds
( Sandmeyer's reaction ) .
RNH 2 HC1 -f HN0 2 RN = N -f 2 H 2 O.
I
Cl
RN = N + Cu 2 Cl, = RC1 + N 2 -h Cu 2 Cl 2 .
Cl
Finely divided metallic copper may be used in place of the
cuprous chloride (Gattermann's reaction).
For iodine derivatives a very clean reaction can often be ob-
tained by mixing such an acid diazonium solution as is described
on pp. 201 and 131 or one containing somewhat more acid, with
an excess of potassium iodide and warming the solution.
The action of hypochlorites, hypobromites, or hypoiodites upon
some organic compounds causes a substitution of halogen atoms
for hydrogen, a reaction which is of very great technical im-
portance in the preparation of chloroform and iodoform. In the
former case, when acetone is used, three hydrogen atoms in one
of the methyl groups appear to be at first replaced by chlorine.
2 CH 3 CO CH 3 + 3 Ca0 2 Cl 2 = 2CC1 3 COCH 3 + 3 Ca(OH) 2 .
The accumulation of negative atoms appears to render the
196 ORGANIC CHEMISTRY
trichloracetone unstable toward bases, and it decomposes in a
manner which recalls the "acid decomposition" of ^-ketonic
acids (see 112).
2CC1 3 COCH 3 + Ca(OH) 2 == 2CHC1 3 + Ca(CH 3 CO 2 ) 2 .
Most of the methods given for the preparation of halogen de-
rivatives of hydrocarbons may also be used for the preparation
of halogen derivatives of other carbon compounds.
Halogen derivatives of acids are prepared by treating the
acid, or, in many cases, either the chloride or bromide of the
acid, with the free halogen. Unless the temperature is unduly
raised so as to cause secondary reactions, aliphatic acids give by
this treatment only a derivatives. (Erlenmeyer: Ber., 14, 1318;
Hell : Ibid, 14, 891 ; Auwers : Ibid, 24, 2209, 2233 ; Michael : J.
prakt Chem. [2], 36, 92; Volhard : Ann., 242, 161.)
3 O,H 2W + I C0 2 H -|- P + nBr = 3 C,,H 2W BrCOBr +
HP0 3 + 5HBr.
ft derivatives may usually be obtained by treating aft unsat-
urated acids with the halogen acids. Bisubstitution products are
obtained by the addition of the free halogen to unsaturated
acids.
The direct treatment of aromatic acids with halogens gives
chiefly meta compounds.
88. Preparation of an Iodine Derivative of a Hydrocarbon from
an Alcohol. Methyl iodide, CH 3 I.
Literature. Dumas, Peligot : Ann., 13, 78; Rieth, Beilstein : Ibid, 126,
250; Walker: J. Chem. Soc., 61, 717.
3 grams red phosphorus.
9 grams methyl alcohol.
25 grams iodine.
Place in a 50 cc. distilling bulb 3 grams of red phosphorus,
add 9 grams (n cc.) of methyl alcohol, and then, in small por-
tions, and with careful cooling 25 grams of iodine. Allow the
mixture to stand in cold water for an hour and then distil from
the water-bath; using a good condenser. Shake the distillate
HALOGEN COMPOUNDS 197
twice with an equal volume of water, separating with a separa-
tory funnel (see 5 1 , p. 127), add once more an equal volume of
water and, with frequent shaking, caustic soda till the methyl
iodide is colorless. Separate again, transfering the iodide to a
small distilling bulb, add some fused, powdered calcium chloride
and distil again from the water-bath after about an hour, using
a thermometer. Yield 20-25 grams.
Methyl iodide boils at 42.8, and has a specific gravity of
2.2852 at 15, or 2.2529 at 25. On heating with fifteen parts of
water at 100 it is converted into methyl alcohol and hydriodic
acid.
Because of its low boiling-point and high molecular weight
it escapes rapidly unless kept in small bottles tightly stoppered
with cork stoppers, or, better, in sealed tubes. A globule of
mercury is sometimes placed in the bottle to remove iodine. For
the preparation of large quantities of ethyl or methyl iodide
the method of Walker (he. cit.) is to be recommended.
89. Preparation of a Bromine Derivative of a Hydrocarbon
from an Alcohol with Sulphuric Acid and Potassium Bromide.
-Ethyl bromide, C 2 H 5 Br.
Literature Serullas : Ann. chim. phys. [2], 34* 99, (1827); Loewig:
Ann., 3i 288; Perkin : J. prakt. Chem., [2], 3*, 497; R- Schiff: Ber., i9i
563; Riedel: Ibid, 24, R. 105.
90 grams potassium bromide.
70 cc. water.
loo cc. alcohol.
100 cc. concentrated sulphuric acid.
10 cc. water.
Put 100 cc. of concentrated sulphuric acid in a flask, add slowly
with constant shaking, but within two or three minutes, 100 cc.
of alcohol. Cool thoroughly and pour the mixture into a 400 cc
distilling bulb or flask containing 90 grams of potassium bro-
mide, and 70 cc. of water. Distil quite rapidly, heating on a
wire gauze covered with a thin sheet of asbestos and using a
good condenser, as long as ethyl bromide comes over. A little
198 ORGANIC CHEMISTRY
water should be placed in the receiver to absorb some hydro-
bromic acid, which is given off. Separate the ethyl bromide
irom the aqueous layer and add to it, with careful cooling,
concentrated sulphuric acid till the acid separates below. This
will remove any ether which has been formed. Separate again,
wash twice with a small amount of water, put the bromide in a
distilling bulb with some fused, powdered ca 1 cium chloride and
distil, with a thermometer, after one or two hours. Yield 55 to
60 grams.
The reactions involved in the preparation are as f o'-lows .
C 2 H 5 OH + H 2 S0 4 C 2 H 5 HS0 4 -j- H 2 O
Ethyl sul-
phuric acid
C 2 H 5 HS0 4 + KBr C 2 H 5 KSO 4 + HBr
Ethyl potas-
sium sulphate
C 2 H 5 KSO 4 -f HBr = C a H 5 Br + HKSO 4 .
Ethyl bromide may also be prepared by the action of bromine
on red phosphorus and alcohol, but the method here given is
more satisfactory and gives a purer product, unless red phos-
phorus free from arsenic is available.
Ethyl bromide boils at 38.4, and has a specific gravity of
1.476 at 15. It must be kept in tightly corked, not glass stop-
pered bottles.
Ethyl bromide is sometimes used as an anaesthetic. For
this use it must be entirely free from arsenic. Arsenic, if pres-
ent, may be detected by burning the substance in a small spirit
lamp, and drawing the products of combustion through a solution
of caustic soda. The solution may then be tested for arsenic
by means of hydrochloric acid and a concentrated solution of
stannous chloride.
90. Preparation of a Bromine Derivative of an Aromatic Hy-
drocarbon. Para-dibrombenzene.
/Br (i)
C 6 H/
X Br (4)
Literature Couper : Ann. chim. phys. [3], 52, 309, (1858) ; Riese : Ann.,
164, 162; Jannasch: Ber., 10, 1355.
HALOGEN COMPOUNDS 199
50 grams benzene (,56.5 cc.).
210 grams bromine (67 cc.).
i gram iron filings.
Put 50 grams of benzene in a dry, 200 cc. flask. Add i gram
of iron filings or turnings, and close the mouth with a stopper
bearing a dropping funnel which dips below the surface of the
benzene, an 1 an exit tube. Put in the dropping funnel,, best out
of doors, 67. cc. of bromine. Place the flask in a water-bath
filled with cold water, and connect the exit tube with a tube
opening just above the surface of water in a large bottle. Allow
the bromine to flow slowly into the benzene. Toward the end,
aid the reaction by heating the water-bath slowly to the boiling-
point.
When the reaction is complete and no more vapors o-f bromine
appear, distil from the flask or from a distilling bulb, collect-
ing the portion boiling at 2oo-23O by itself. Crystallize from
a small amount of alcohol. Yield 50 to 60 grams of p-dibrom-
benzene.
Para-dibrombenzene crystallizes in white prisms or leaflets
which melt at 89, and boil at 219.
91. Substitution of Chlorine in the Side Chain of an Aromatic
Hydrocarbon. Benzyl chloride, C 6 H 5 CH 2 C1.
Literature. Cannizzaro : Ann., 96, 246; Beilstein, Geitner : Ibid, i39
332; Lauth, Grimaux : Ibid, M3 80; Schramm : Ber., 18, 608: Haase : Ibid,
26, 1053.
loo grams toluene.
100 grams manganese dioxide.
540 Cc. commercial hydrochloric acid.
Put in a 200 cc. flask 100 grams (115 cc.) of toluene and con-
nect it with an upright condenser. Place in the upper end of the
condenser a tight stopper bearing two glass tubes, one passing
just through the stopper and the other reaching nearly to the
bottom of the flask. Connect the first tube with a tube opening
just above the surface of water in a 'bottle. Or arrange one
tube passing through the stopper beside the condenser, and con-
nect the other with the top of the condenser, as in Fig. 38
200
ORGANIC CHEMISTRY
Heat the toluene to boiling and pass in chlorine generated in a
liter flask by the slow addition of 540 cc. of commercial hydro-
chloric acid to loo grams of manganese dioxide, the mixture be-
ing warmed gently and the gas purified by passing it through a
wash-bottle containing water, and then through one containing
concentrated sulphuric acid. The operation must be carried out
in clearjdaylight, or, if possible, in the direct sunlight.
Fig. 38.
When the evolution of chlorine has ceased, submit the product
in the flask to fractional distillation. The portion boiling below
150 consists chiefly of unchanged toluene and may be used for
a new preparation. After fractioning two or three times the
portion boiling at i76-i8i will consist of nearly pure benzyl
chloride. The yield varies according to the brightness of sun-
light in which the operation is conducted. In some cases the
weight of benzyl chloride may equal that of the toluene used.
Benzyl chloride is a colorless liquid with an unpleasant odor.
Its vapor attacks the eyes very strongly. It boils at 178 and has
a specific gravity of 1.113 at I 5- By long 1 boiling- with water it
HALOGEN COMPOUNDS 2OI
is converted into benzyl alcohol. Oxidizing agents oxidize it
to benzoic acid. The higher boiling portions contain some benzal
chloride, C 6 H 5 CHC1 2 , which boils at 203.5.
92. Preparation of a Bromine Derivative of a Hydrocarbon from
an Aromatic Amine. Parabromtoluene,
/CH 3 (i)
C 6 H/ . ._^
||r (4)
Literature Hiibner, \\~allacri: Afn'., 154, 293; Glinzer, Fittig: Ibid,
J 36, 301; Michaelis, Genzken : Ibid, 242, 165; Ladenburg: Ber., 7, 1685;
Sandmeyer: Ibid, 17, 2652; Schramm : Ibid, 18, 606; Gasiorowski u.
Wayss: Ibid, 18, 1936; Gattermann : Ibid, 23, 1218; Erdmann : Ann., 272,
141 ; Heller : Z. angew. Chem., 23, 389.
25 grams copper sulphate.
72 grams potassium bromide.
9 grams (5 cc.) sulphuric acid (1.84).
10 grams reduced copper or copper bronze, "Natur Kupfer C."
160 grams water.
21.4 grams para-toluidine.
80 cc. water.
29 grams sulphuric acid (15.7 cc).
100 grams ice.
14 grams sodium nitrite.
70 cc. water.
In a liter flask put 25 grams (i mol.) of crystallized copper sul-
phate, 72 grams (6 mols.) of potassium bromide, 100 cc. of water,
10 grams of reduced copper, or copper bronze, "Natur Kupfer
C," and 9 grams (5 cc., i mol.) of concentrated sulphuric acid.
Heat on an asbestos plate with an upright condenser to gentle
boiling till the solution is colorless. Meanwhile put in a beaker
21.4 grams (2 mols.) of paratoluidine, add 80 cc. of water and
29 grams (15.7 cc., 3 mols.) of concentrated sulphuric acid.
The toluidine should dissolve in the hot solution to insure its
complete conversion into the sulphate. Stir and cool till the
sulphate has separated in finely divided condition. Add 100
grams of ice and. when the temperature has fallen to o. add
202 ORGANIC CHEMISTRY
slowly, with stirring, 14 grams (2 mols.) of sodium nitrite dis-
solved in 70 cc. of water. After standing for five minutes the
solution should react for nitrous acid when a drop is placed
on starch potassium iodide paper. If it does not, a little more
of the nitrite must be added, but the least possible excess must
be used. Neither the diazonium solution, nor that of the cup-
rous bromide should be allowed to stand long after they are
prepared, because of the tendency of the former to decompose.
and of the latter to oxidize.
Cool the cuprous bromide solution very slightly, and add the
diazonium solution slowly, shaking vigorously and warming the
solution on a vigorously boiling water-bath. The whole of the
solution should be added within two to three minutes, if possible
without cooling it too far. The diazonium solution is best add-
ed through a funnel with a long, wide stem dipping beneath the
cuprous bromide solution.
It is impossible in any case, apparently, to secure a perfectly
clean reaction. Three different reactions may take place:
= N + H 2 = C 7 H 7 OH + N,+ HBr.
Br
N + Cu 2 Br 2 C 7 H 7 N=NC 7 H 7 + N 2 + 2CuBr 2 .
Br
C 7 H 7 N = N + Cu 2 Br 2 C 7 H 7 Br + N 2 + Cu,Br,.
Br
The first reaction takes place if the diazonium solution
poses before it is added to the cuprous bromide, or if it is added
to the hot solution in such a manner that it is not immediately
mixed with it, so that the diazonium compound has no oppor-
tunity to combine with the cuprous bromide. Hence the neces-
sity of vigorous shaking to secure a rapid and thorough mixture
of the solutions. The second reaction is apparently favored
when the diazonium-cuprous bromide remains in the cool solu-
tion undecomposed. The best conditions for the reaction appear
to be secured at the lowest temperature of rapid decomposition
HALOGEN COMPOUNDS 2O3
for the diazonium-cuprous compound. This temperature varies
in different cases. It is much higher for toluene para diazonium-
cuprous bromide than for the ortho compound, apparently be-
cause of the greater stability of the former. (See Erdmann: loc.
*.)
When the diazonium solution has all been added, distil over
the parabromtoluene in a rapid current of water vapor (see 22, p.
71), shake it with some sodium hydroxide solution to remove any
paracresol present, separate it from the solution, dry by allowing
it to stand for some time with solid caustic potash, pour off or
filter through a dry filter, and distil from a small distilling bulb,
using a condensing tube or distilling slowly into a bottle or tube.
Yield about 20 grams.
Parabromtoluene crystallizes in rhombic plates, which melt at
28.5. It boils at 185.2, and has a specific gavity of 1.3897 at
20
o . Oxidizing agents convert it into parabrombenzoic acid.
4
93. Preparation of a Bromine Derivative of an Acid. Hell-
Volhard-Zelinsky's Method. a-Bromobutyric acid, CH 3 CH 2 CH
Br.CO.,H. Bromo (2)-butanoic acid.
Literature Borodin: Ann., 119, 121; Xaumann : Ibid, 119, 115; Hell:
Ber., 14* 891; 21, 1726; Volhard: Ann., 242, 141; Ber., 21, 1904; Zelinsky:
Ibid, 20, 2026: Auwers and Bernhardi : Ibid, 24, 2216: Hell and Lauber :
Ibid, 7, 560.
17.6 grams butyric acid.
2.2 grams red phosphorus.
60 grams bromine (20 cc.).
Select a small Liebig condenser whose inner tube will pass
just inside of the neck of a 50 cc. round-bottomed flask. Cut
off the lip of the flask, put the end of the condenser in its mouth
and connect by means of a rubber tube, which slips over both,
as is done with some forms of condensers. (See Fig. 39).
Put in the flask 2.2 grams (^3 at.) of red phosphorus, and 17.6
grams (i mol.) of normal butyric acid. Add slowly from a
dropping tube with a glass stop-cock, or from a bulb drawn out
to a capillary below, through the top of the condenser, 60 grams
204
ORGANIC CHEMISTRY
( 11 /s at.) of bromine. The bromine is best measured from a
dry burette or measuring tube, in a good hood or out of doors.
The top of the condenser should be closed with a doubly per-
forated stopper, one hole carrying the dropping tube, and the
other a tube leading out of doors or just over the surface of a
solution of caustic soda in a bottle. Drop in the bromine slowly,
and warm very gently on a water-bath till the vapors of bromine
disappear, usually about an hour. Cool, and pour the contents
of the flask, in small portions, upon 50 grams of ice in a flask.
Fig. 39-
Shake vigorously, keeping the contents of the flask cold, till the
bromide of the bromobutyric acid is decomposed, and the odor of
phosphorus oxybromide has disappeared. Separate the acid,
from the aqueous solution, wash it once with a small amount
of water, and distil it under diminished pressure. The portion
boiling at I35-I4O, under a pressure of 35 mm. will be nearly
pure.
In working with a small amount of acid the bromination may
be effected with advantage by putting a weighed quantity of the
acid in a sealed tube, converting it into the chloride by the cal-
HALOGEN COMPOUNDS 205
culated amount of phosphorus pentachloride, putting in a bulb
containing two atoms of bromine for one molecule of the acid,
Dealing the tube, breaking the bulb containing the bromine by
shaking the tube, and heating, till vapors of bromine disappear,
in a water-bath. On cooling and opening the tube the phos-
phorus oxychloride may be decomposed by shaking with cold
water and, in case the chloride of the acid is not readily decom-
posed in this way, it may be taken up with ether, the solution
dried with calcium chloride, the ether distilled, and the chloride
decomposed by warming with glacial formic acid. See Baeyer :
Ann., 245, 175; Aschan: Ibid, 271, 265.
a-Bromobutyric acid boils with some decomposition at 212-
217. It boils without decomposition at I36-I38 under a
pressure of 35 mm. The specific gravity at 15 is 1.54. It
dissolves in about 15 parts of water. When treated with alcoholic
H C C0 2 H
potash it is converted into cis-crotonic acid, ||
H C CH 3
The yield is, however, poor, owing to the formation of hydroxy-
butyric acid and other substances.
94. Preparation of the Bromine Derivative of an Ester by Direct
Bromination. Ethyl ester of monobromomalonic acid.
Br C0 2 C 2 H 5
\ p/
/\
H C0 2 C 2 H 5
Literature Knoevenagel: Ber., 21, 1356; Conrad and Bruckner: Ber.,
2 4, 2997; Condensation to ethylene tetracarboxylic ester (Dicarbintetra-
carboxyl ester) Blank and Sampson: Ber., 3 2 > 860.
30 grams ethyl malonic ester.
30 grams (9.6 cc.) bromine.
Put in a loo cc. distilling bulb 30 grams of malonic ester.
Insert in the neck of the bulb a rubber stopper bearing a separa-
tory funnel. Put in the separatory funnel 30 grams (i mol.
= 9.6 cc.) of bromine. Connect the side tube of the bulb with a
tube which will deliver the hydrobromic acid evolved over water
in a 500 cc. bottle but the tube should not dip below the surface
2C>6 ORGANIC CHEMISTRY
of the water. The whole operation should be carried out in a
good hood. Drop the bromine into the ester slowly with constant
shaking and warming at first to 40 -50 to start the reaction.
After all of the bromine has been added warm gently for a
short time, on the water-bath, till the mixture becomes nearly
colorless. Cool thoroughly, add in small portions with constant
cooling a ten per cent, solution of sodium carbonate till the solu-
tion remains alkaline to litmus after shaking. Transfer to a
separatory funnel and draw off the bromomalonic ester below,
first filling the funnel nearly full of water and agitating gently so
that none of the heavy liquid floats in globules on the surface.
Dry the ester with calcium chloride, pour off or filter into a
Claissen distilling bulb (p. 172) and distil under diminished
pressure. The portion boiling at I2o-i25 under a pressure of
14 mm. is sufficiently pure for most purposes but retains some
dibromomalonic ester which cannot be entirely removed by
fractionation. The diethylester of bromomalonic acid boils at
235 with some decomposition and has a specific gravity of
1.426 at 15.
95. Preparation of a Chlorine Derivative of a Hydrocarbon
by the Use of Calcium Hypochlorite. Chloroform, CHC1 3 , trichlo-
romethane.
Literature Soubeiran : Ann. chim. phys. [2], 48, 131 (1831); Liebig:
Ann., i, 199; Belohoubek: Ibid, 165, 349; Goldberg: J. prakt. Chem. [2],
24, 109 (1881) ; Bechamp: Ann. chim. phys. [5], 22, 347 (1881) ; Orndorff
and Jessel : Am. Chem. J., 10, 365 ; E. R. Squibb : J. Am. Chem. Soc., 18,
231.
. 150 grams bleaching powder.
450 cc. water.
12 grams (16 cc.) acetone.
35 cc. water.
Put in a liter flask 150 grams of bleaching powder (containing
33 per cent, available chlorine), add 450 cc. of water, and insert
a stopper bearing a dropping funnel, a bent tube leading to a
condenser, and a third tube leading nearly to the bottom of the
flask. Introduce through the dropping funnel, slowly and
HALOGEN COMPOUNDS 2O 1 /
with frequent shaking, a mixture of 16 cc. of acetone with 35 cc.
of water. After the acetone has all been added and the flask no
longer grows warm spontaneously, distil the remainder of the
chloroform by passing in a current of steam. Shake the chlo-
roform several times with small quantities of water, separate, dry
by allowing to stand with fused calcium chloride, and distil from
the water-bath without separating from the calcium chloride.
Yield about 20 grams.
Chloroform is a colorless liquid with an ethereal odor and a
sweetish taste. It boils at 61, and has a specific gravity of
i. 5039 at 5 , and of 1.5264 at 5-. Pure chloroform de-
4 4
composes slowly, especially in the sunlight, with liberation of
chlorine, hydrochloric acid, phosgene, and other substances.* The
addition of one per cent, of alcohol renders it more stable. Pure
chloroform should not impart an acid reaction to water with
which it is shaken, nor should it react with a solution of silver
nitrate in the cold.
96. Preparation of an Iodine Derivative of a Hydrocarbon by
the Action of Iodine and Sodium Carbonate on Ethyl Alcohol.
lodoform, CHI 3 , triiodomethaneu
Literature Serullas : Ann. chim. phys. [2], 22, 172 ; 25, 311 ; Bouchardat :
Ann., 22, 225 ; Spindler : Ann., 231, 263 ; Forster, Meyer : J. prakt. Chem.
[2], 56, 354; Elbs, Herz: Chem. Zentralbl, 1897, II, 695: Quantitative
determination, Greshoff : Z. anal. Chem., 29, 209 ; 3 2 , 361 ; Schacherl :
Chem.-Zentralbl, 1897, I, 568.
10 grams crystallized sodium carbonate (or 3.6 grams of the
anhydrous salt).
50 cc. water.
10 grams alcohol.
10 grams iodine.
In a loo cc. flask dissolve 10 grams of crystallized sodium car-
bonate (or 3.6 grams of the anhydrous salt) in 50 cc. of warm
water, add 10 grams of alcohol, warm to 7o-8o and add in por-
tions 10 grams of iodine, but do not add iodine after the iodine
color no longer disappears after warming for a short time.
2C>8 ORGANIC CHEMISTRY
Cool, filter and wash the iodoform. Dissolve it in 15-20 cc. of
ether, wash the solution twice with water, dry it with calcium
chloride and allow the ether to evaporate spontaneously in a
small beaker or crystallizing dish. Yield 2-3 grams.
Iodoform crystallizes in leaflets or in hexagonal plates which
melt at 119. It is volatile with water vapor and is a powerful
germicide.
Chapter XII
4
NITRO COMPOUNDS
The nitro derivatives of aromatic compounds have been long-
est known and are most easily prepared. For a long time it was
thought that nitro derivatives of hydrocarbons of the marsh
gas series could not be prepared by the direct treatment of hy-
drocarbons with nitric acid. Kon'owalow has shown, however,
(Ber., 28, 1852, and 29, 2199), tnat such compounds may, in
many cases, be prepared by the use of dilute nitric acid, and
nitro compounds of the homologues of benzene may be pre-
pared containing the nitro group in the side chain by the same
method.
The method more usually employed for the preparation of
nitro compounds of the aliphatic series consists in treating alkyl
iodides with silver- nitrite.
RI + AgNCX = R NO 2 + Agl.
With aromatic hydrocarbons nitration is effected sometimes by
adding the hydrocarbon or other compound to the nitric acid,
and sometimes by the reverse process.
RH + HNO 8 = RNO 2 + H 2 O.
As the reaction is accompanied by a considerable evolution of
heat, the mixture must usually be made carefully, and in many
cases cooling is necessary. The strength of acid and the tem-
perature required vary greatly in different cases. Sometimes
it is necessary to reinforce the acid by the use of a mixture
with concentrated sulphuric acid. In general it is better to use
such a mixture and moderate the action by cooling rather than to
use nitric acid alone at a higher temperature. Benzene deriva-
tives with side chains are more easily nitrated than benzene
itself.
The nitro group usually enters in the para or ortho position
with reference to CH,, C 2 H 5 , OH, NH 2 , CI, Br, or I, but mainly
14
2IO ORGANIC CHEMISTRY
in the meta position toward CO 2 H, SO 3 H, CHO, CN, C1 3 , or
NO 2 . In the case of the amino group it is sometimes possible
to cause the group to enter in the ortho or meta position at will
by changing the conditions, or by introducing the acetyl group in
the amino group.
In order to secure a nitro group in a desired position it is
often necessary to introduce two groups, and then eliminate one
of them by reduction to the amino group and subsequent elimina-
tion of the latter through the diazonium reaction.
R _ N = N + C,H 5 OH == RH + C,H 4 O -f HNO 3 -f N,.
N0 3
Primary and secondary nitro compounds are soluble in solu-
tions of alkalies with the formation of salts having the struc-
x ONa
ture, = C = NXf (Nef : Ann., 280, 263; Ber., 29, 1218).
Tertiary nitro compounds, and nitro compounds of the aromatic
series except nitrophenols (Hantsch), do not form compounds of
this character.
Mononitro compounds of benzene and its homologues are
volatile with water vapor, and may frequently be separated from
dinitro compounds and other substances by this means.
The reduction of nitro compounds to amines and other com-
pounds will be considered in the following chapter.
The nitration of toluene has already been given on p. 126.
97. Nitration of an Aromatic Hydrocarbon. Nitrobenzene.
Literature Mitscherlich : Ann., 12, 305.
50 grams of benzene.
60 grams nitric acid. (1.42).
80 grams sulphuric acid (1.84).
Put 50 grams of benzene in a 300 cc. flask. Drop in slowly,
with vigorous shaking and during about 15 minutes a cooled
mixture of 60 grams of nitric acid (1.42) and 80 grams of sul-
phuric acid (1.84). Cool in running water so that the tempera-
ture does not rise above 5o-6o. When all of the acid has
NITRO COMPOUNDS 211
been added and the temperature no longer rises on vigorous
shaking, place the flask on the water-bath and heat for half
an hour with frequent shaking. Cool again, pour the contents
of the flask into 300 cc. of cold water, separate the nitrobenzene
from the acid solution, wash it once with water, dry with calcium
chloride and distil.
Nitrobenzene solidifies at a low temperature and melts at 5.
It boils at 210 and has a specific gravity at 2 7 4 ^ of 1.2033.
98. Preparation of a Dinitro Compound by Direct Nitration.
X N0 2 (i)
w-Dinitrobenzene, C 6 H 4 ^
X N0 2 (3)
Literature Deville: Ann. chim. phys., [3], 3 187 (1841); Muspratt,
Hofmann: Ann., 57, 214; Beilstein, Kurbatow : Ibid, 176, 43; Willgerodt:
Ber., 25, 608 ; V. Meyer, Stadler : Ibid, 17, 2649.
20 grams benzene (23 cc.).
50 cc nitric acid (1.42).
50 cc. concentrated sulphuric acid.
loo cc. concentrated sulphuric acid.
Put in a 300 cc. flask 20 grams (23 cc.) of benzene and add
in small portions a cooled mixture of 50 cc. of nitric acid (sp.
gr. 1.42) with 50 cc. of concentrated sulphuric acid. Shake
vigorously after each addition and cool somewhat, to prevent too
violent a reaction. When the mixture has all been added and
the whole shaken vigorously for some minutes, add in small por-
tions and shaking as before, but without cooling, 100 cc. of con-
centrated sulphuric acid. Heat to about 120, allow to cool to
about 80, and pour, with stirring, into 1500 cc. cold water. Fil-
ter off the dinitrobenzene and crystallize from alcohol. Yield
30 to 32 grams.
Metadinitrobenzene crystallizes in needles which are colorless
and odorless. It melts at 91 and boils without decomposition
at 297. 100 parts of alcohol at 20 dissolve 3.5 parts. Easily
soluble in hot alcohol. Practically insoluble in water.
or
212 ORGANIC CHEMISTRY
NO,
99. a-Nitronaphthalene,
Literature Laurent: Ann. chim. phys., [2], 59, 378; Beilstein, Kuhlberg:
Ann., 169, 83 ; Liebermann : Ibid, 183, 235 ; Piria : Ibid, 78, 32 ; Aguiar :
Ber., 5, 370.
20 grams naphthalene.
100 grams nitric acid (sp. gr. 1.33).
55 cc. nitric acid (sp. gr. 1.42).
25 cc. water.
Put in a beaker 20 grams of naphthalene, add 100 grams (75
cc.) of nitric acid (sp. gr. 1.33) and allow to stand for several
days. Dilute with water, filter, wash and dry. Moisten with a
very little alcohol and treat with carbon bisulphide, which dis-
solves the mononitro compound. Filter from the insoluble dinitro
compound, and evaporate the solution to dryness. (Beware of
flames.} The solution can be evaporated on a previously heated
water-bath in a hood, all flames in the neighborhood being extin-
guished. Recrystallize from alcohol. Yield 17 grams.
a-Nitronaphthalene crystallizes in fine yellow needles which
melt at 61. It boils at 304. It gives by oxidation nitrophthal-
ic acid, while the aminonaphthalene obtained by its reduction
gives by oxidation phthalic acid.
By reduction it gives a-naphthtylamine which is used for the
determination of nitrites in potable waters.
100. Preparation of a Nitro Derivative of an Amine and Elim-
/CH 3 (i)
ination of the Amino Group. w-Nitrotoluene, C 6 H 4 <(
X N0 2 (3)
Literature Monnet, Reverdin, Nolting: Ber., 12, 443; Nolting, Witt:
Ibid, 18, 1336 ; Buchka : Ibid, 22, 829 ; Noyes, Moses : Am. Chem. J., 7>
149; Noyes: Ibid, 10, 475; Schraube, Romig: Ber.. 26, 579.
NITRO COMPOUNDS 213
20 grams paraacetotoluide.
75 cc. nitric acid (1.42).
30 cc. concentrated sulphuric acid.
50 cc. alcohol.
10 grams potassium hydroxide.
13 cc. water.
15 grams nitrotoluidine.
60 cc. absolute alcohol.
12 cc. concentrated sulphuric acid.
8 grams (9 cc.) ethyl nitrite.
Prepare acetotoluide by boiling paratoluidine with twice its
weight of glacial acetic acid for two hours (see acetanilide, p.
157), pouring into cold water, filtering off, washing and drying.
Add 20 grams of the finely powdered substance in small por-
tions to a mixture of 75 cc. of nitric acid with 30 cc. of con-
centrated sulphuric acid. Stir with a thermometer during the
addition, and keep the temperature between 30 and 40 by
setting the beaker in cold water. When all has been added al-
low the beaker to stand for fifteen minutes and then pour the mix-
ture into cold water, filter off the nitroacetotoluide, wash and suck
and press as dry as possible on a plate. Put the substance in a
flask, add 50 cc. of alcohol, heat nearly to boiling, and add care-
fully a solution of 10 grams of potassium hydroxide in 13 cc.
of water. Heat on a water-bath for twenty minutes. Cool
thoroughly, filter off the nitrotoluidine on a plate, wash with alco-
hol diluted with two volumes of water, and dry thoroughly.
Put 15 grams of the nitrotoluidine in a 300 cc. flask and add
a warm mixture of 60 cc. of absolute alcohol with 12 cc .of con-
centrated sulphuric acid; cool thoroughly and add slowly with
vigorous shaking and cooling, 7.5 grams of ethyl nitrite (see 122,
p. 250). Allow to stand a few minutes, and then warm on the
water-bath till the evolution of nitrogen ceases. Cool, precipitate
the nitrotoluene by adding water, siphon off or decant most of the
aqueous solution, and distil the nitrotoluene which remains, in a
current of steam (see 22, p. 71). A small amount of nitrotolu-
214 ORGANIC CHEMISTRY
ene may be obtained by extracting the alcoholic mother-liquors
with ether, but in most cases it is not worth while to do that.
Separate the nitrotoluene from the water of the distillate, and dry
it in vacuo over sulphuric acid. Yield 8 to 10 grams.
Instead of the method given here, Meyer and Jacobson ad-
vise in their text-book (Vol. II, p. 158) to dissolve the nitroto-
luidine in a mixture of three parts of alcohol and three parts,
by weight, of concentrated sulphuric acid, cool, add the theoreti-
cal amount of sodium nitrite dissolved in the smallest possible
amount of water, and then warm on the water-bath as above.
In our experience the yields obtained in this way are much less.
Instead of adding ethyl nitrite, the mixture of nitric oxide
and nitrogen peroxide (usually called nitrous anhydride), ob-
tained by boiling arsenious oxide with nitric acid (sp. gr. 1.30-
1.35), may be passed into the acid alcoholic solution till it smells
strongly of the nitrous ester after standing a short time, or ethyl
nitrite may be passed in as it is generated at such a temperature
as to assume the gaseous form (see 122, p. 250).
Paraacetotoluide crystallizes in rhombic needles which melt at
153. It boils at 307.
3~Nitro-4-acetotoluide crystallizes from water in fine yellow
needles which melt at 94-95.
3-Nitro-4-toluidine crystallizes in red prisms, wnich melt at
Ii6-ii7. It is volatile with water vapor.
Meta-nitrotoluene melts at 16, and boils at 23O-23i. By
the chromic acid mixture it is oxidized to meta-nitrobenzoic acid.
By an alkaline solution of potassium ferricyanide it is much less
easily oxidized than ortho- or paranitrotoluene.
loi. Preparation of a Nitro Derivative of an Amine. />-amino-
(I)
150.
NITRO COMPOUNDS 215
10 grams />-toluidine.
100 grams concentrated sulphuric acid. (sp. gr. 1.84).
7.5 grams nitric acid (sp. gr. 1.48).
30 grams concentrated sulphuric acid.
500 cc. ice-water.
400 grams acid sodium carbonate.
Dissolve 10 grams of paratoluidine in 200 grams (120 cc.) of
cold concentrated sulphuric acid. Cool to o with a freezing
mixture (the most convenient is snow or ice and concentrated
commercial sulphuric acid, snow and salt is a little cheaper),
and drop in slowly a mixture of 7.5 grams (5 cc.) of nitric
acid (sp. gr. 1.48),- with 30 grams (17 cc.) of concentrated sul-
phuric acid, stirring and keeping the temperature below 5.
Allow the mixture to stand for half an hour, and pour into 500
cc. of ice-water, keeping the temperature below 25. Filter, add
looo cc. of water and neutralize with baking soda. About 400
grams will be required. Filter off and wash the precipitated
nitrotoluidine, and crystallize from dilute alcohol. Yield about
10 grams.
. In this nitration the large amount of sulphuric acid forms an
acid sulphate with the toluidine, and appears in that way to so
change the character of the amino group that the nitro group
enters in the meta position wijth regard to it. Compare the
preceding preparation.
Orthonitroparatoluidine crystallizes from water in broad, yel-
low, monociinic needles, which melt at 77.5.
102. Preparation of a Nitro Derivative of an Aromatic Acid.
xCCXH (i).
Meta-nitro-benzoic acid, C 5 H 4 <^
X N0 2 (3).
Literature Mulder: Ann., 34> 297; Gerland : Ibid, 91, 186; Griess: Ber..
8, 526; 10, 1871; Widmann: Ann. 193, 202: C. Liebermann : Ber., 10,
862; Ernst: Ztschr. chem., 1860, 477.
25 grams benzoic acid.
50 grams potassium nitrate.
75 grams absolute sulphuric acid (monohydrate).
2l6 ORGANIC CHEMISTRY
Warm 75 grams of absolute sulphuric acid 1 to 70 in a beaker,
and add, in small portions, a powdered mixture of 25 grams of
benzoic acid and 50 grams of potassium nitrate, stirring vig-
orously and keeping the temperature at So -go . When all has
been added, and the nitrobenzoic acid has separated as an oily
layer on the surface of the liquid, pour the contents of the beaker
into a porcelain dish, and allow the product to solidify. Separate
the cake of nitro acids from the acid potassium sulphate. Put
the nitro acids (about 75 per cent, of meta, 22 per cent, of the
ortho, and 2^ per cent, of the para acids are present in the mix-
ture) in a beaker with 100 cc. of water, heat till the acids melt, and
stir thoroughly. Cool, filter, and wash with cold water. Dis-
solve the acid, in 300-400 cc. of hot water, and add a clear con-
centrated solution of barium hydroxide (about 30 grams) to
alkaline reaction. Cool, filter, and wash. The barium salts of
the ortho and para acids pass into the filtrate, while a part of the
ortho acid remained in solution on treatment with water before.
The pure meta acid can be obtained by treating the barium salt
with 200 cc. of hot water and some sulphuric acid, filtering
hot from the barium sulphate, which separates, and cooling the
filtrate.
Meta-nitro-benzoic acid melts at 141- 142. It dissolves in
10 parts of hot water, and in 425 parts of water at 16.5. It
is very easily soluble in alcohol and ether. The barium salt is
soluble in 19 parts of boiling water, and in 265 parts of cold
water.
The ortho and para acids may also be separated from the
mixture obtained by the nitration of benzoic acid, but are more
readily obtained by the oxidation of the nitro-toluenes. (See
51, p. 126.)
1 Absolute sulphuric acid, called technically the "monohydrate," can be purchased or
may be prepared by cooling concentrated sulphuric acid to o or below, until it crystal-
lizes and pouring off the liquid portion, the crystals consisting of absolute sulphuric acid,
if the acid is sufficiently strong. The crystallization may be started with crystals obtained
by cooling a mixture of ordinary sulphuric acid with the fuming acid.
Chapter XIII
AMINES
The simplest method of preparing amines, and one which usually
gives pure compounds, consists in reducing nitro compounds.
RNO 2 + 6H = RNH 2 + 2H 2 O.
The reducing agents generally used are tin and hydrochloric
acid, iron and acetic acid (in manufacture), ammonium sul-
phide, and stannous chloride. This method of preparation is
general with aromatic compounds, but is not often used for
members of the marsh gas series, because of the difficulty of ob-
taining the nitro compounds required.
A method of great historical importance consists in treating
halogen derivatives with an aqueous solution of ammonia.
RBr + NH 3 = RNH 2 HBr.
The ease with which secondary and tertiary amines, and
quaternary ammonium salts are formed by this reaction detracts
from its usefulness, as the resulting mixtures are often difficult
of separation. (For a method of separation see pp. 160 and
267.)
To overcome the difficulty which arises from the formation of
secondary and tertiary amines when halogen compounds are
treated with ammonia, Gabriel has used, successfully, potassium
phthalimide. When this is heated with halogen compounds to
[5O-2OO in sealed tubes or open vessels, according to the nature
of the halogen compound, derivatives of the phthalimide are
formed. These may be saponified with separation of the chloride
of the primary amine by heating in sealed tubes at 200, with
three parts of fuming hydrochloric acid. (Ber., 20, 2224; 21,
566.2669.),
/CO, /COv
RC1 f C 6 H 4 < >NK = C.H 4 < >NR + KC1.
X CCK
/COv /COOH
C 6 H 4 < >NR 4- 2H,0 4 HC1 = C.H 4 < + RNH 2 HC1.
X CCK X COOH
2l8 ORGANIC CHEMISTRY
Another method of attaining the same end, which seems very
general in its application, has been worked out by Delepine
(Compt. rend., 120, 501; 124, 292). On heating hexamethylene
amine with halogen compounds in solution in chloroform, double
compounds are produced. When these are heated gently with
alcohol and concentrated hydrochloric acid they are decomposed
with the formation of a primary amine and methylene-diethyl
ether.
C 6 H 12 N 4 + RC1 = C 6 H 12 N 4 /
NCI
/R
C 6 H 12 N/ + i2C 2 H 6 + 3 HC1 = 3 NH 4 C1 +
Cl
)C 2 H 6
RNHHC1 + 6CH
OC 2 H 5
The method has been successfully used for the preparation of
benzyl amine and of allyl amine.
A very useful method consists in the reduction of oximes and
hydrazones.
-n T>
'\C = NOH + 4 H = \CHNH, + H 2 O.
R'/ R'/
R \ R \
>C = NNHC 6 H 5 + 4 H = >CHNH 2 + C 6 H 5 NH 2 .
R'/ R'/
The best reducing agent for the oximes appears to be absolute
alcohol and sodium. The same method may also be applied to
hydrazones, or the latter may be reduced by zinc dust and acetic
acid in alcoholic solutions.
Nitriles may be reduced to amines by absolute alcohol and so-
dium, and in some cases, also, by the use of zinc and hydrochloric
or sulphuric acid.
R _ c = N + 4 H R CH 2 NH 2 .
When acid amides are treated with bromine and sodium hy-
droxide, or, in many cases, if treated with an alkaline solution of
AMINES 219
sodium hypobromite, they are converted into amines with loss of
carbon dioxide.
R CONH 2 + NaOBr + 2NaOH == RNH 2 -f NaBr -f
H 2 O + Na 2 CO s .
The most plausible explanation of this reaction appears to be
that given by Stieglitz, based on the work of Nef (Am. Chem.
J-> 18, 751).
R CONH 2 -f NaOBr R CO NHBr + NaOH.
R C O
| w + NaOH == R C = O + NaBr + H 2 O.
N -nitrosodimethyl- or diethylaniline with caustic
soda.
/N(C,H 6 ), xONa
. C 6 H 4 < -f NaOH - C 6 H/ + NH(C 2 H 5 ) 2 .
\NO X NO
Complex amines containing chromophore groups and of im-
portance as dyes may be prepared by a great variety of methods,
especially by condensations, of which the preparation of mala-
chite green (p. 241) is an illustration. Heterocyclic compounds
in which the nitrogen atom forms a. part of the ring and in which
the nitrogen may or may not have the property of combining
with acids to form salts are also prepared in many ways. The
preparation of pyridine, piperidine, [uinoline, p. 238), indigo,
(p- 2 35)> an d collidine dicarboxylic acid ester are typical of
many similar preparations.
When a ketone or aldehyde is treated with a concentrated aque-
ous solution of potassium cyanide and ammonium chloride the
hydrocyanic acid and ammonia, present in such a solution by
hydrolysis, condense with the ketone or aldehyde to form an
a-amino nitrile. (Zelinsky, Stadnikoff. Ber., 39, 1/26).
R, R, /NH,
>CO + NH 3 + HCN - > C < 4 H 2 O.
R/ R/ \CN
The nitrile may be saponified to an a-amino acid by hydro-
chloric acid.
R v /NH. R x xNH.,
> C < + HC1 + 2H 8 = > C < + NH 4 C1.
R/ \CN W X CO 2 H
103. Tlie Preparation of an Amine by the Reduction of a Nitro
Compound. Aniline, C 6 H 5 NH S .
Literature. Unverdorben : Pogg. Ann., 8, 397; Runge: Pogg. Ann.,
31, 65; 3 2 > 331; Fritsche: Ann., 36, 84; 39> 76; Anderson: Ibid, 70, 32;
Hofmann : Ibid, 55> 200; 53, n; Wohler : Ibid, 102, 127; Merz, Weith :
AMINES 221
Ber., 13* 1298; Merz, Miiller : Ibid, ig 2916; Reverdin, Harpe : Ibid, 22,
1004.
25 grams nitrobenzene.
45 grams tin.
100 cc. commercial hydrochloric acid.
Put into a 500 cc. flask 25 grams of nitrobenzene and 45 grams
of tin. Add about 10 cc. of commercial hydrochloric acid,
(sp. gr. 1.16), and shake vigorously. If the solution becomes so
hot as to boil, cool it somewhat by dipping the flask in cold water.
When the reaction moderates add 10 cc. more of the acid, and
continue in the same manner till 100 cc. have been added
Warm on the water-bath till the odor of nitrobenzene disappears.
Cool, add, with further cooling if necessary, a solution of 75
grams of caustic soda in 100 cc. of water, and distil off the sepa-
rated aniline with water vapor, distilling about 100 cc. after the
distillate ceases to appear turbid. Add to the distillate 20 to 30
grams of salt and some ether, separate the ethereal solution,
dry it by allowing it to stand for some time, best over night,with
some powdered caustic potash, ptfur off into a distilling bulb,
distil the ether from the water-bath, and then the aniline with a
free flame. Yield 15 to 17 grams.
Aniline is a colorless oil with a slightly aromatic odor. It
melts at 8, boils at 183.7, an d has a specific gravity of 1.036
at o, and 1.0276 at 11.6. Aniline forms salts which crystallize
well, but these react acid toward test papers. Aniline dissolves
in 31 parts of water at 12.5. The hydrochloride is easily soluble
in alcohol and in water, and melts at 192. It is less easily soluble
in hydrochloric acid, a characteristic which may be used with ad-
vantage in the crystallization and purification of many of the
chlorides of organic bases. Aqueous solutions of aniline give
a violet color on the addition of a few drops of a solution of cal-
cium hypochlorite (chloride of lime).
104. Preparation of a Nitre-Ammo Compound by the Re-
duction of a Dinitro Compound. /-amino-0-mtrotoluene,
/CH 3 (i)
C K H S -NO, (2) .
(4)
222 ORGANIC CHEMISTRY
Literature See 101, p. 214; also Beilstein and Kuhlberg: Ann., i55, 13
15 grams toluene.
35 cc. nitric acid (1.42).
35 cc. sulphuric acid.
75 cc. sulphuric acid.
15 grams dinitrotoluene.
50 cc. alcohol.
8 cc. ammonia. (0.90).
Hydrogen sulphide.
Put 15 grams of toluene in a small flask and add in small
portions, 70 cc. of a mixture of equal volumes of concentrated
sulphuric and concentrated nitric acids, shaking vigorously and
cooling somewhat. After the mixture has all been added and the
reaction moderates, add 75 cc. of concentrated sulphuric acid,
shake vigorously, heat to about 130 and keep the mixture at that
temperature, shaking vigorously for about 15 minutes. Allow
to cool, pour into water, filter, wash, and crystallize the dinitro-
toluene from alcohol. 20 to 25 grams of pure dinitrotoluene,
melting at 70.5, should be obtained.
Put 15 grams of the dinitrotoluene in a flask, add 50 cc of
alcohol and 8 cc. of concentrated ammonia (0.90), pass in a
rapid current of hydrogen sulphide nearly to saturation, connect
the flask with a reversed condenser or condensing tube, and
heat on a water-bath for half an hour. Cool, saturate again
with hydrogen sulphide, and heat as before. Filter hot, cool the
filtrate, add water, and filter off the precipitated nitrotoluidine
after standing for some time. Purify by dissolving in dilute
hydrochoric acid, filtering, and precipitating again with am-
monia. Yield about 10 grams.
Orthonitroparatoluidine crystallizes from water in broad yel-
low monoclinic needles, which melt at 77.5. It is difficultly solu-
ble in water and carbon bisulphide, easily soluble in alcohol and
acids.
AMINES 223
105. Preparation of a Diamino Derivative of Benzene.
/NH, (i)
^-Phenylenediamine, C 6 H 4 ^ (/>-Diaminobenzene).
X NH 2 (4)
Literature Grethen : Ber., 9, 775 ; Beilstein, Kurbatow : Ann., 197, 83 ;
Nolting, Collins: Ber., 17, 262; Hobrecker: Ibid, 5, 920.
20 grams acetanilide.
75 cc. nitric acid (142).
30 cc. sulphuric acid (1.84).
20 grams nitroacetanilide.
30 grams tin.
80 cc. commercial hydrochloric acid.
Hydrogen sulphide.
Lime.
Prepare />-nitroacetanilide exactly as directed for nitroacet-
toluide (see p. 213). Put in a flask 20 grams of nitroacetanil-
ide and 30 grams of tin. Add 10 cc. of concentrated com-
mercial hydrochloric acid, and shake till the reaction begins to
moderate ; add more of the acid and shake as before, and con-
tinue till 80 cc. of acid have been added. Then heat on the water-
bath till the reaction is complete. The nitro group is reduced
and the acetyl group is alsq removed. Dilute with three or four
volumes of water, pour off from any undissolved tin, precipitate
the tin from the solution with hydrogen sulphide, and filter on a
Witt Plate or Hirsch funnel (see p. 120). The hydrogen sulphide
is best generated in a two-liter acid bottle from considerably
more than the theoretical amount of iron sulphide, which is
placed in the bottle with 1500 cc. of water. Somewhat more than
the theoretical amount of concentrated commercial sulphuric
acid is then added, in small portions, through the thistle tube.
The gas should be passed through a washing tube or wash-bottle
containing a little water. After the operation is over, the gener-
ator should be emptied at once, as the ferrous sulphate would
crystallize on standing. If any unused ferrous sulphide is left in
the bottle, and the latter is filled up at once with water to prevent
its oxidation, it can be saved for use again.
224 ORGANIC CHEMISTRY
Evaporate the filtrate to a small volume, filter again, if neces-
sary, through a hardened filter, and allow the chloride of the
phenylenediamine to crystallize.
To prepare the free amine, mix the chloride with an equal
weight of quicklime, and distil from a small retort. The para-
phenylenediamine may be recrystallized from benzene. Yield
10 to 12 grams.
Paradiaminobenzene crystallizes from benzene in shining leaf-
lets, which melt at 140 and boil at 260. It is moderately soluble
in hot water.
Paranitroacetanilide melts at 207.
1 06. Preparation of an Amine by the Decomposition of an Alkyl
Derivative of Aniline. Diethylamine, (C 2 H 5 ) a NH.
Literature. Hofmann : Ann., 74, 128, 135; Elsbach : Ber., 15, 690;
Piutti: Ann., 227, 182; Pictet : Ber., 20, 3422; Schloemann : Ibid, 26, 1020;
Reynolds: J. Chem. Soc., 61, 457; Kopp : Ber., 8, 621; Lippmann u.
Fleissner: Ibid, 16, 1422; Hofmann: Ann., 73, 91; Wallach : Ibid, 214,
275 ; Reinhardt and Staedel : Ber., 16, 29 ; Baeyer and Caro : Ibid, 7>
963.
30 grams aniline.
45 grams ethyl bromide.
20 grams sodium hydroxide.
60 cc. water.
35 grams ethyl aniline.
45 grams ethyl bromide.
20 grams sodium hydroxide.
60 cc. water.
30 grams diethylaniline.
150 cc. water.
120 cc. concentrated hydrochloric acid (1.19).
loo grams ice.
1 6 grams sodium nitrite.
80 cc. water.
70 grams sodium hydroxide.
210 cc. water.
225
Put in a small flask 30 grams of aniline and 45 grams of ethyl
bromide, and heat with a reversed condenser for one or two
hours, or until the mass solidifies. Cool, add 60 cc. of a solution
of sodium hydroxide (3 cc. I gram), with cooling, separate
the ethyl aniline, add to it 45 grams of ethyl bromide, and heat
with reversed condenser as before, till the mass solidifies. Dis-
solve in water, boil to expel any ethyl bromide which remains,
cool, add 60 cc. of caustic soda, and separate the diethyl aniline.
Dry with powdered potassium hydroxide, and distil, collecting
as much as possible of the portion boiling at 212 -2 15. (Ani-
line boils at 183.7, ethyl aniline at 206, and diethyl aniline at
213.5.)
Dissolve 30 grams of the diethyl aniline in 120* cc. of concen-
trated hydrochloric acid and 150 cc. of water, cool, add 100
grams of ice, and when the solution is near o add slowly, with
stirring, 16 grams of sodium nitrite dissolved in 80 cc. of water.
After an hour transfer the solution of nitrosodiethyl aniline,
/NO
C 6 HX , to a liter flask and add carefully, with shaking,
210 cc. of a strong solution of sodium hydroxide, connect with
a condenser by means of a bent tube, and distil, collecting the
distillate in a flask containing 20 cc. of concentrated hydrochloric
acid. The solution remaining in the flask may be used for the
preparation of paranitrosophenol.
The hydrochloric acid solution will contain diethylammonium
chloride, some ethyl aniline regenerated from nitrosoethyl aniline
which has distilled over, some .diethyl aniline, and probably other
substances. Evaporate on the water-bath to about 50 cc., trans-
fer to a 200 cc. flask, cool thoroughly, add, with cooling, 60 cc. of
sodium hydroxide (3 cc. = I gram), connect the flask by means
of a tightly fitting cork, with a glass tube one cm. in diameter
and about 60 cm. long, and held in a clamp at an angle of 45
with the perpendicular. About 15 cm. of the upper end of the
tube, which serves as a reflex condenser, should be bent down-
ward and this should dip into a flask containing 10 cc. of con-
centrated hydrochloric acid. If the lower portion of the tube
15
226 ORGANIC CHEMISTRY
is filled with glass beads a better separation will be effected. Dis-
til very slowly, in such a manner that the ethyl aniline and simi-
lar substances almost entirely condense and run back. Sometimes
it may be necessary to neutralize the distillate with 50 cc. of
sodium hydroxide, and distil again before a pure distillate can be
obtained. Finally evaporate the solution of diethylammonium
chloride nearly or quite to dryness, transfer to a flask or distilling
bulb, decompose with a very concentrated solution of sodium or
potassium hydroxide, and distil from the water-bath. To obtain
the amine free from water it must be dried with fused caustic
potash and distilled again. Yield 7 to 8 grams. ^
Diethyl amine boils at 55-56, and has a specific gravity of
0.7028 at 25. The hydrochloride melts at 2i5-2i7, boils at
32o-33O, and is very easily soluble in water, but difficultly solu-
ble in absolute alcohol.
107. Preparation of an Amine from an Oxime. Isopropyl
3X , 2
amine, x^x (2-atninopropane.)
Literature Sierch: Ann., 148, 263; Gautier: Ann. chim. phys., [4],
17, 251; Hofmann: Ber., 15, 768; Taf el : Ibid, 19, 1926; Goldschmidt: Ibid,
20, 728; Noyes: Am. Chem. J., i4i 226; 15, 540.
10 grams acetoxime.
20 grams sodium.
240 cc. absolute alcohol.
Put in a 200 cc. round-bottomed flask 20 grams of sodium,
connect with a long, reversed condenser, and pour through the
latter a solution of 10 grams of acetoxime in 60 cc. of absolute
alcohol. By means of a short tube, bent twice at right angles
and passing through rubber stoppers, connect the top of the
condenser with a U-tube containing 5 to 6 cc. of concentrated
hydrochloric acid. Because of the low boiling-point of iso-
propyl amine this is necessary, but with amines of higher molecu-
lar weight it is not required. When the first violent action
slackens, warm on an asbestos plate and add from time to time
through the condenser, more alcohol, whenever a crust forms
on the sodium. About 240 cc. of alcohol will be required. When
AMINES 227
the sodium has all dissolved, add 40 cc. of water through the
condenser, cool, and then distil off the alcohol and isopropyl
amine, collecting in a flask containing 12 cc. of concentrated hy-
drochloric acid, including that from the U-tube. Evaporate to dry-
ness, and preserve the amine in the form of its hydrochloride.
Yield 8 to 10 grams.
Isopropyl amine boils at 31.5, and has an ammoniacal, fishy
odor. Its specific gravity is 0.690 at 18. The hydrochloride is del-
iquescent and melts at i53-i55 cf . The chloroplatinate is diffi-
cultly soluble, and melts at 227-228. The salt is easily pre-
pared by adding chloroplatinic acid, ("platinic chloride"),
H,PtCl 6 , to a concentrated solution of the chloride. It can be
analyzed by careful ignition in a porcelain crucible.
108. Preparation of an Amine by the Reduction of a Cyanide.
o>-Phenyl-ethyl-amine, C 6 H 5 CH,CH 2 NH 2 . ( i l -amino-ethylphen.)
Literature Cannizzaro: Ann., 96, 247; Mann: Ber., 14, 1645; Stadel:
Ibid, 19, 1951 ; Hotter : Ibid, 20, 82 ; Spica, Columbo : Gaz. chim. ItaL,
5. 124; Bernthsen: Ann., 184, 304; Ladenburg: Ber., 18, 2956; 8, i9i 782;
Hofmann: Ibid, 18, 2740; Hoogewerf, van Dorp: Rec. trav. chim. Pays-
Bas., 5> 254; Filed, Piccini: Ber., 12, 1700.
30 grams benzyl chloride.
38 cc. alcohol.
18 grams potassium cyanide.
17 grams water.
5 grams benzyl cyanide.
6 grams sodium.
70 cc. absolute alcohol.
8 cc. hydrochloric acid (sp. gr. i.io).
Put in a round-bottomed flask 18 grams of pure powdered
potassium cyanide, 17 cc. of water, 30 grams of benzyl chloride,
and 38 cc. of alcohol. Connect with an upright condenser, and
boil on a wire gauze or asbestos plate for 3 to 4 hours. By
means of a separatory funnel separate the alcoholic solution,
containing the benzyl cyanide, from the lower aqueous layer and
distil the former. The alcohol and water may be distilled with
advantage from a water-bath under diminished pressure and the
228 ORGANIC CHEMISTRY
heating continued till the residual liquid is dry (see 55, p. 138).
In any case the portion boiling at 2io-24O will, if dry, be
sufficiently pure for this preparation. Yield of benzyl cyanide
20 to 22 grams.
Put in a 200 cc. round-bottomed flask 6 grams of sodium, cut
in small pieces, add a warm solution of 5 grams of benzyl cy-
anide in 30 cc. of absolute alcohol, connect with an upright con-
denser, and heat rapidly to boiling. Continue to boil and add
more alcohol as necessary, in all 70 to 80 cc., till the sodium is
dissolved. Distil off the alcohol and the phenylethylamine in a
current of steam, distilling as long as the distillate comes over
alkaline. Add to the distillate 8 cc. of hydrochloric acid, evapo-
rate to a small volume, filter, and evaporate to dryness. Transfer
the residue to a small test-tube, dissolve in 2 to 3 cc. of hot water,
cool, add 8 cc. of sodium hydroxide (3 cc. = i gram), and a
few cc. of ether, and shake vigorously. Allow the ethereal
layer to separate, and by means of a pipette with a fine capillary
tube, remove as much as possible of the aqueous solution from
below. Pour off the ethereal solution into a dry tube, rinse with
a little ether, and dry the ethereal solution by adding solid caustic
potash and leaving it for 24 hours. Transfer to a small (15 cc.
or less) distilling bulb, and distil the ether through a condenser
and then the amine directly into a small preparation tube. Yield
about 2.5 grams of the hydrochloride, and 1.5 grams of the dis-
tilled amine.
This method of reducing cyanides' led Ladenburg to the syn-
thesis of cadaverine from trimethylene cyanide,
CNCH 2 CH 2 CH 2 CN.
With ethylene cyanide and phenyl cyanide it gives less satisfac-
tory results, owing, in the latter case, to secondary reactions
which give partly benzene and sodium cyanide and partly so-
dium benzoate and ammonia.
Benzyl cyanide boils at 231.7. o>-Phenyl-ethylamine is a col-
orless liquid which has a slightly ammoniacal odor, and boils at
198. It has a specific gravity of 0.958 at 24.4. It is a strong base.
It is somewhat soluble in water, and is easily soluble in alcohol
AMINES 229
and ether. The hydrochloride, C 6 H 5 CH 2 CH 2 NH 2 HC1, crystal-
lizes from absolute alcohol in leaflets or plates, which melt at 217
and dissolve in i l /4 parts of water at 14. It is less easily solu-
ble in hydrochloric acid, easily soluble in alcohol. The chloro-
platinate is difficultly soluble in cold water.
109. Benzyl Amine. C 6 H 5 CH,2NH 2 , Aminomethylphen.
Literature Mendius : Ann., 121, 144; Bamberger, Ladter: Ber., 20,
1709; Cannizzaro: Ann., i34 128; Hof mann : Ber., 18, 2738; Taf el : Ibid,
iQi 1928; Curtius, Lederer: Ibid, 19, 2463; Leuckhart, Bach: Ibid, 19*
2128; Goldschmidt : Ibid, 19, 3232; Mason: J. Chem. Soc., 63, 1313;
Seelig: Ber.,- 23, 2971; Hoogewerf, van Dorp: Rec. trav. chim. Pays-Bas.,
5. 253 ; Delepine : Compt. rend., 120, 501 ; 124, 292.
50 cc. formaldehyde solution (40 per cent. ).
50 cc. ammonia (sp. gr. 0.90).
10 grams hexamethylene amine.
10 grams benzyl chloride.
30 cc. chloroform.
1 6 grams double compound of hexamethylene amine with
benzyl chloride.
45 cc. alcohol.
15 cc. concentrated hydrochloric acid.
Put in a 150 cc. distilling bulb 50 cc. of a 40 per cent, solu-
tion of formaldehyde and add in small portions, cooling some-
what, 50 cc. of ammonium hydroxide (0.90). Heat for 5 to 10
minutes on a water-bath, put in the mouth of the bulb a rubber
stopper bearing a fine capillary tube (see 75, p. 171), and distil
as rapidly as possible from the water-bath, under diminished
pressure, till the residue of hexamethylene amine appears dry.
Rinse out the amine with a mixture of two volumes of ether
with one volume of ajcohol and suck off on a Witt plate. Wash
with a little ether and dry on the water-bath. 10 grams of the
amine should be obtained. A small additional quantity of amine
may be obtained from the alcohol-ether mother-liquors.
Put in a small flask 10 grams of the hexamethylene amine, 30
cc. of chloroform, and 10 grams of benzyl chloride. Connect
with an upright condenser, and boil gently on a water-bath for
230 ORGANIC CHEMISTRY
half an hour. Allow to cool, filter, and wash with a little
chloroform. About 16 grams of the double compound,
/CH 2 C 6 H 5
C 6 H 12 N 4 <^ , should be obtained. An additional small
\C1
amount of the compound will separate from the mother-liquors
on standing.
Put in a distilling bulb 16 grams of the double compound, last
mentioned, and 60 cc. of a mixture of three volumes of alcohol
and one volume of concentrated hydrochloric acid. Connect with
an upright condenser, and heat on a water-bath for an hour,
then distil from the water- bath the methylenediethyl ether,
/OC 2 H 5
CH 2 2690; Preparation, Baum : Ber., 19, 502; From urine of the horse
or cow, Gregory: Ann., 63, 125.
2.5 grams aminoacetic acid.
30 cc. sodium hydroxide (10 per cent.).
4.5 grams benzoyl chloride.
Dissolve 2.5 grams (1/30 mol.) of glycocoll 1 in 30 cc. of a
ten per cent, solution of sodium hydroxide, add 4.5 grams (1/30
mol.) of benzoyl chloride and shake till the odor of the chloride
disappears. Filter, if the solution is not clear, and precipitate
the hippuric acid with a slight excess of hydrochloric acid.
Recrystallize from hot water.
1 Instead of free glycocoll the necessary amount of the copper salt may be dis-
solved in water and the copper precipitated as directed oil p. 231. The filtrate from the
copper sulphide may then be evaporated to a small volume and the solution used as
directed.
AMINES 233
Hippuric acid crystallizes in thick needles which melt at 187.5.
The preparation of hippu'ric acid here given is closely related
to the preparation of polypeptides by Fischer and the formation
of hippuric acid in the animal organism is very probably re-
lated to the synthesis of proteins in the processes of life.
112. Preparation of an a-Amino Acid Through the Amino-
nitrile. a-Aminoisobutyric acid, (CH 8 ) a CHNH 2 CO 2 H.
Literature Urech : Ann., 164, 268 ; Tiemann, Friedlander : Ber.. 14*
1971; Zelinsky, Stadnikoff : Ber., 39 1/26.
13 grams potassium cyanide.
10.6 grams ammonium chloride.
Water to dissolve each.
1 1. 6 grams acetone.
Concentrated hydrochloric acid.
Dissolve separately 13 grams (^5 mol.) potassium cyanide
and 10.6 grams (j/s mol.) of ammonium chloride in two small
flasks. Put the solution of ammonium chloride into a 100 cc.
strong, glass stoppered bottle, add n.6 grams ( l /s mol.) of ace-
tone, then the solution of potassium cyanide, insert the stopper,
mix quickly and tie the stopper down by means of a piece of
cloth placed over the top and tied tightly around the neck of the
bottle. Allow the mixture to stand in a warm place (4O-5O)
over night. Transfer the solution to a strong, round-bottomed
flask and add (under the hood} an equal volume of concentrated
hydrochloric acid. Connect with an upright condenser and boil
for two hours. Pour the solution into an evaporating dish and
evaporate to dryness either on the water-bath or on an asbestos
plate, but in the latter case care must be taken that the residue
is not overheated. Transfer the residue to a flask and extract
it repeatedly with a mixture of 10 parts of alcohol with one of
ether, which will dissolve the hydrochloride of the amino acid
but will leave the inorganic salts undissolved.
Distil off the alcohol and ether, dissolve the hydrochloride
of the amino acid in a small amount of water, add twice the
theoretical amount of lead carbonate and warm on the water-
234 ORGANIC CHEMISTRY
bath till effervescence ceases. Cool thoroughly, filter on a plate
and suck as dry as possible, moisten once with a very little water
and suck off again. Remove the lead contained in the nitrate
by means of hydrogen sulphide, and evaporate the filtrate till
the amino acid crystallizes. Yield 15 grams.
a-Aminoisobutyric acid crystallizes in plates which sublime at
28o-28i without melting. It is very easily soluble in water/'
difficultly soluble in alcohol, insoluble in ether.
113. Preparation of an Amino Acid from the Half Amide of a
/CO,H (i)
Bibasic Acid. Anthranilic acid, C 6 HX (2-Amino-
X NH 2 (2)
benzoic acid).
Literature Laurent : Jahresb., 1847-48, 589 ; Ann., 39, 91 ; Kuhara :
Am. Chem. J., 3, 29; Aschan : Be.r.,ig, 1402; Fritzsche : Ann., 39i 83;
Beilstein, Kuhlberg: Ibid, 163, 138; Bedson : J. Chem. Soc., 37, 752,
(1880) ; Hoogewerf, van Dorp: Rec. trav. chim. Pays-Bas., 10, 6, Marig-
nac: Ann., 42, 215.
20 grams phthalic anhydride.
80 cc. ammonia (0.96).
64 cc. hydrochloric acid (1.112).
16.5 grams phthalamidic acid.
100 cc. sodium hydroxide, (10 per cent.).
140 cc. sodium hydroxide (10 per cent.).
1 6 grams bromine (5.1 cc.).
35 cc. hydrochloric acid (1.112).
40 cc. acetic acid (30 per cent.).
Add 20 grams of finely powdered phthalic anhydride in por-
tions to 80 cc. of ammonia (sp. gr. 0.96 not stronger as strong
ammonia may cause the formation of phthalimide) in a 200 cc.
flask, shaking and cooling the mixture. When the anhydride is
nearly dissolved filter and to the filtrate add 64 cc. of hydro-
chloric acid (4 cc. = i gram), cool again thoroughly with shak-
ing, filter off on a plate, stop the pump> moisten with water, suck
AMINES 235
off and repeat once. Dry the phthalamidic acid, C 6 H/^ ,
\CONH 2
on filter-paper in the air, or, better, in vacua over sulphuric acid.-
The yield should be about 20 grams.
Put 140 cc. of a ten per cent, solution of sodium hydroxide
in a flask, add from a burette 16 grams (5.1 cc = I mol.) of
bromine, and dissolve it immediately by giving the flask a quick
rotary motion. 1 Dissolve 16.5 grams (i mol.) of phthalamidic
acid in 100 cc. of ten per cent, sodium hydroxide, and add the
solution of sodium hypobromite in portions of about 20 cc. at
intervals of one to two minutes, cooling after each addition.
Neither solution should stand but a few minutes before use.
Allow the mixture to stand for half an hour, add a little of a
strong solution of acid sodium sulphite to reduce the excess of
sodium hypobromite, and 35 cc. of hydrochloric acid (4 cc. =
I gram), carefully, on account of the effervescence. Evapo-
rate to about 100 cc. Filter, if necessary and add 40 cc. of
acetic acid (30 per cent.). Filter off the anthranilic acid after
cooling, suck it as free as possible of the mother-liquors and
recrystallize from hot water. Yield 10 to n grams.
For a discussion of the reactions involved in the transforma-
tion of the amide group into an amino group with loss of car-
bonyl see p. 219.
Anthranilic acid crystallizes in leaflets which melt at 144-
145. It is easily soluble in water. The aqueous solution shows
a blue fluorescence and tastes sweet.
The preparation of anthranilic acid from indigo is of especial
historic interest. The acid may also be prepared by the reduc-
tion of orthonitrobenzoic acid.
114. Preparation of Indigo from Anthranilic Acid,
/CO v /CO v
C.H 4 < >C:C/ >C 6 H,
/ \/
1 A hypobromite solution more nearly free from bromate may be prepared by putting
the bromine in a glass-stoppered wash-bottle, set in warm water and aspirating the vapor
of the bromine into the solution of sodium hydroxide contained in two wash-bottles set
in cold water.
236 ORGANIC CHEMISTRY
Literature Baeyer's synthesis of indigo: Ber., n, 1228, 1296; 13*
2254 ; Heumann's synthesis : Ber., 23, 3431 ; Mauthner and Suida : Mon-
atsh, 9, 728; History of the synthesis of indigo, Baeyer: Ber., 33> LI;
Brunck: Ber., 33, LXXI ; Henle : Anleit. zur org. prap. Prakticum, p. 63.
6.8 grams anthranilic acid.
5.7 grams chloracetic acid.
8.5 grams dry sodium carbonate.
50 cc. water.
Hydrochloric acid.
4 grams phenylglycine-0-carboxylic acid.
17 cc. sodium hydroxide (10 per cent).
10 grams sodium hydroxide.
10 grams potassium hydroxide.
Put 6.8 grams of anthranilic acid, 5.7 grams of chloracetic
acid, 8.5 grams of dry sodium carbonate and 50 cc. of water in
a 200 cc. flask, connect with an upright condenser and boil for
2 to 3 hours. Cool, add hydrochloric acid in slight ex-
cess, filter off the precipitated phenylglycine-0-carboxylic acid,
xNHCH 2 CO 2 H
C 6 H/ , after standing for some hours and recrys-
x:o 2 H
tallize it from water.
Dissolve 4 grams of the phenylglycine-o-carboxylic acid in
17 cc. of sodium hydroxide (10 per cent.), evaporate the so-
lution to dryness on the water-bath and dry the powdered resi-
due at 140.
In a not too small nickel crucible melt 10 grams of sodium
hydroxide and 10 grams of potassium hydroxide and heat till
the water is expelled and the hydroxides are in a state of quiet
fusion. Cool to 270, measuring the temperature with a ther-
mometer enclosed in a copper or iron tube, closed below. Add
the sodium salt previously prepared, stir and keep the mixture
at 26o-2jo for ten or fifteen minutes. This treatment
AMINES 237
causes the condensation of the acid to indoxylic acid,
NH
C(OH)
When the mass is cold, dissolve it in 50 cc. of water and boil
gently for half an hour. This causes the loss of carbon
dioxide and conversion of the indoxylic acid to indoxyl,
NH
C.HA >^CH. Add 100 cc. of water and draw or blow a
C(OH)
rapid current of air through the solution for several hours. This
will cause the oxidation and condensation of two molecules of
indoxyl to one of indigo. Yield about i gram.
115. Preparation of a Complex Secondary Amine from a
Primary Amine and a Bromine Derivative of an Ester. Ani-
/C0 2 C 2 H 5
inomalonic ester, C 6 H.NHCH<
X CO a C 2 H 5
Literature Curtiss : Am. Chem. J., ig 691.
11.95 grams ethyl ester of bromomalonic acid.
9.3 grams aniline.
Put in a small flask 11.95 grams (0.05 mol.) of the ethyl
ester of bromomalonic acid and 9.3 grams (o.i mol.) of aniline.
Allow the mixture to stand over night and then complete the
reaction by warming for half an hour on the water-bath. Cool,
add ether gradually to precipitate the aniline hydrobromide and
dissolve the ester. Filter from the hydrobromide, wash the
ethereal solution in a separatory funnel two or three times with
5 per cent, sulphuric acid to remove aniline and once or twice
with water. Dry the solution with fused potassium carbonate,
and evaporate the ether to crystallization. The ester may be
purified by recrystallization from alcohol. It crystallizes in
needles which melt at 44 -45. Yield almost quantitative.
238 ORGANIC CHEMISTRY
CH N
CH C CH
116. Skraup's Synthesis of Quinoline. | II |
CH C CH
CH CH
Literature Gerhardt: Ann., 42, 310; 44, 279; Baeyer: Ber., 12, 460,
1320; Konigs: Ibid, 12 ,,453; 13, 911; Wyschnegradsky : Ibid, 12, 1480;
Skraup, Monatshefte, i, 317; 2, 141; J. Walter: J. prakt. Chem., 49
549 ; Knueppel : Ber., 2Q 703 ; Marckwald : Ann., 279, 3.
24 grams nitrobenzene.
38 grams aniline.
100 grams concentrated sulphuric acid.
120 grams glycerol.
Put in a liter flask the mixture given above, connect with a
wide upright condenser, warm slowly till the reaction just begins, 1
remove the flame quickly till it moderates, and then boil for two
hours. Cool somewhat, add 100 cc. of water, and distil in a
current of steam (see 22, p. 71) as long as the distillate smells
of nitrobenzene. Cool, add 300 cc. of caustic soda (3 cc. =
i gram), and distil over the quinoline with a current of steam.
To destroy the aniline which is present, add to the distillate
50 cc. of concentrated hydrochloric acid, and then a strong solu-
tion of sodium nitrite, till the solution smells of nitrous acid.
Heat to boiling till the diazonium compound is decomposed ;
add 100 cc. of caustic soda, and distil the quinoline again with
water vapor. Collect the quinoline with a little ether, distil off
the ether, dry the residue with solid caustic potash, pour off, and
distil. Yield about 40 grams.
Quinoline boils at 237. It gives an orange-yellow, difficultly
soluble precipitate with chloroplatinic acid, (C 9 H 7 N) 2 H 2 PtCl 6 .
The nitrobenzene used in the synthesis acts as an oxidizing
agent, and Knueppel has shown that it may be replaced with
advantage by arsenic acid. The reaction is ,
C 6 H 5 NH 2 + C 3 H 8 3 + O = C 9 H 7 N + 4 H 2 O.
1 If this operation is conducted carelessly the reaction may become explosively vio
lent.
AMINES 239
The same reaction may be applied to a great many derivatives
of benzene, naphthalene and anthracene.
117. Preparation of a Quinazoline from an Acyl Anthranilic
Nitrile. 2.7-Dimethyl-4-ketodihydroquinazoline or 2.7-Dimethyl-
4-hydroxyquinazoline.
/N --= C.CH, /N - C.CH S
CH 3 C 6 H 3 / n CH 3 C 6 H/ |
\CO NH \COH- N
Literature General discussion of quinazolines, Bogert: J. Am. Chem.
Soc., 3 2 784; Preparation of Dimethyl-ketodihydroquinazoline, Bogert
and Hoffman: J. Am. Chem. Soc., 27, 1296, 1299.
4 grams homoanthranilic nitrile.
5 cc. acetic anhydride.
1.5 grams acetyl homoanthranilic nitrile.
50 cc. potassium hydroxide (10 per cent.).
50 cc. hydrogen peroxide (3 per cent).
/CH, i.
Put 4 grams of homoanthranilic nitrile, 1 C 6 H 3 NH 2 3. ,
\CN 4.
and 5 cc. of acetic anhydride in a long test-tube and boil gently
with a micro burner for two hours, covering the mouth of the
tube with a small watch-glass and taking care not to boil so vig-
orously that the anhydride escapes. Pour the solution into water
and crystallize the acetyl homoanthranilic nitrile from dilute
acetic acid and from alcohol. It crystallizes in colorless needles,
which melt at 136.
Put 1.5 grams of acetyl homoanthranilic nitrile in a 150 cc.
flask, add 50 cc. of a 10 per cent, solution of potassium hydroxide
and 50 cc. of a 3 per cent. ("10 volume") solution of hydrogen
peroxide and warm at 4O-5o for two hours. The alkaline
X CH 3 I.
1 The nitro nitrile, CeH 3 NOo 3. , may be prepared by Sandmeyer's reaction (p. 131)
^CN 4.
from wx-nitro-^-toluidine (p. 213) (see Bogert and Hoffman, J. Am. Chem. Soc., 27, 1294
Bogert and Hand, Ibid, (24, 1035) Noyes, Am. Chem. J., 10, 477). The nitro-nitrile is re-
duced to tht amino-nitrile by stannous chloride and hydrochloric acid (Bogert and Hoff-
man, J. Am. Chem. Soc., 27, 1295).
240 ORGANIC CHICMISTKV
hydrogen peroxide solution saponifies the nitrile to the amide
and the latter condenses to form the quinazoline. The latter dis-
solves either in strong acids or in strong bases (why) ? Add
10 cc. of concentrated hydrochloric acid (1.19) and then a
slight excess of ammonia. Crystallize the precipitated quinazo-
line from alcohol.
2.7-Dimethyl-4-ketodihydroquinazoline crystallizes in needles
which melt at 255.
118. Preparation of a Derivative of Pyridine by Condensation.
CH 3
C
/%
- Collidinedicarboxyllic ester, C H 5 CO, C C CO 2 C 2 H 6 .
II
C C
/ v \
CH 3 N CH 3
Literature Hantsch : Ann., 215, 8; Michael: Ibid, 225, 123; Bamberger :
Ber., 24, 1763.
20 grams acetoacetic ester.
5 grams aldehyde ammonia.
10 grams dihydrocollidinedicarboxyllic ester.
Arsenious anhydride.
Nitric acid (sp. gr. 1.30-1.33).
Put in a small beaker 20 grams of acetoacetic ester, and add
five grams of aldehyde ammonia. Warm gently till the reac-
tion begins, remove the flame for a short time, and then boil, with
stirring, for four or five minutes in all. Add a little alcohol,
and allow to cool till the dihydrocollidinedicarboxyllic ester crys-
tallizes; filter, wash once with dilute alcohol, and then with
water. A small amount of less pure ester may be obtained by
diluting the filtrate.
The reaction takes place in some such manner as the follow-
ing:
AMINES 241
CH 3
C 2 H 5 CO, C ;OH H; C^OH HiCH CO 2 C,H 5 =
ir : \ : i:i::/
CH N;H 2 0;C
CH 3 CH 3
CH 3
C.,H 5 CO, C == C CH C0 2 C.,H S
4- 3H,0.
CH 3 CH N = C CH :i
Put 10 grams of the crude ester in a small flask, add 20 cc. of
alcohol, and pass in a rapid stream of the oxides of nitrogen,
generated by warming arsenious oxide with nitric acid of sp.
gr. 1.301.33, passing the gases through an empty Drechsel
wash-bottle to condense water. Rubber connections must be
avoided as far as possible, because the gas attacks them. Con-
tinue the passage of the gas till a drop of the solution dissolves
clear in dilute hydrochloric acid. Evaporate the alcohol on the
water-bath, add ?. strong solution of sodium carbonate, and take
up the collidinedicarboxyllic ester with ether. Dry the ethereal
solution with ignited potassium carbonate, and distil from a small
distilling bulb. Yield 7 to 8 grams.
The dihydro ester crystallizes in colorless plates, which melt
at 131. Its solutions show a beautiful blue fluorescence. It is
almost insoluble in water, and in dilute acids, difficultly soluble
in cold alcohol, easily soluble in hot alcohol, and in chloroform.
It dissolves in concentrated hydrochloric or sulphuric acid.
Collidinedicarboxyllic diethyl ester boils at 308 -310. It is
easily saponified by alcoholic potash, giving a potassium salt
difficultly soluble in alcohol. Collidine may be obtained from this
potassium salt by mixing it with calcium hydroxide and distil-
ling.
119. Preparation of a Leuco Base and Dye by Condensation of
an Aldehyde with an Aromatic Amine. Malachite Green.
( /,C 6 H 4 ~= N(CH 8 ),Cn
3 I C H. -- C< | . 2ZnCl,.2H,O.
\C.H 4 -N(CHJ, !
242 ORGANIC CHEMISTRY
Literature. Condensation of aromatic hydrocarbons with aldehydes,
Baeyer: Ber., 6, 963; Preparation of Leucomalachite green, O. Fischer:
Ann., 206, 83, 122, 129; Dobner: Ann., 217, 250-253; E. Fischer: Anleiting
z. Darst, org. Praparte, p. 71 ; Henle : Anleitung zur anorg. prap. prakti-
cum p. 153; Preparation and constitution of rosaniline and pararosaniline,
O. and E. Fischer: Ann., 194, 242, 285; Ber., n, 1079; 13, 2204; Crystal-
violet, Hofmann : Ber., 18, 767; Carbinol and quinoid formulae, Friedlander:
Ber., 26, 173; Nomenclature and classification of triphenylmethane dyes r
Baeyer and Villiger : Ber., 37, 597, 2848; Theory of colored and colorless
compounds, Hantsch : Ber., 33, 278, 752 ; 38, 2143 ; Gomberg : Ber., 40, 1868,
1875; Baeyer and Villiger: Ber., 37, 597, 2848; 38, 569; Ann., 354> 152;
Wilstatter : Ber., 41, 1458 ; Curtiss : J. Am. Chem. Soc., 3 2 795 ; Isorrepsis,
Baly and Stewart: J. Chem. Soc., 89, 498, 513; Development of the coal
tar dyes, Caro : Ber., 25, R. 955.
12 grams dimethyl aniline.
5 grams benzaldehyde.
10 grams fused zinc chloride.
3.3 grams leuco base.
40 cc. normal hydrochloric acid.
2.4 grams lead peroxide.
3.5 grams zinc chloride.
Saturated solution of salt.
Put 12 grams of dimethylaniline, 5 grams of benzaldehyde and
10 grams of fused zinc chloride in a porcelain dish and warm
on a water-bath for some hours, stirring occasionally and add-
ing a few drops of water if the mixture becomes too vis-
cous. Transfer the mixture to a flask or distilling bulb and
drive out the excess of dimethyl aniline with a current of
steam. Cool, pour off the aqueous solution of zinc chloride,
dissolve the leuco base, tetramethyldiaminotriphenylmethane,
4 - N(CH 8 ),
, in a considerable amount of hot
C 6 H 4 N(CH 3 ) 2
alcohol, filter, if the solution is not clear, and allow to crystal-
lize. If the base separates as an oil at first, dissolve again in
more alcohol. After the crystals have been separated an ad-
ditional crop may be obtained by evaporating the mother-liquors.
The base melts at 102.
,
CH^
\
AMINES 243
Dissolve 3.3 grams of the leuco compound in 40 cc. of hot,
normal hydrochloric acid, dilute with 300 cc. of water and add
gradually, with vigorous shaking, 2.4 grams of lead peroxide
mixed with about 20 cc. of water 1 . Shake vigorously for about
10 minutes in all. Add an aqueous solution of 3.5 grams of zinc
chloride and then, gradually, a saturated solution of salt until a
portion of the mixture gives a colorless nitrate. Filter and wash
once with a salt solution. Dissolve the compound in hot water
and reprecipitate again with a saturated salt solution.
Dissolve a little of the malachite green in strong hydrochloric
acid and note the effect of dilution with water. Dissolve some
of the dye in water and add ammonia, then dilute hydrochloric
acid. Reduce some of the substance to the leuco base by means
of zinc and dilute hydrochloric acid. See Dobner: Ann., 217,
251 and 252.
1 The per cent, of pure lead peroxide in the reagent must be known and enough
taken to give 2.4 grams of the pure compound.
Chapter XIV
DIAZO, HYDRAZO, NITROSO AND OTHER
NITROGEN COMPOUNDS
A considerable number of other nitrogen compounds beside
amines and nitro derivatives are known. Most of these are ob-
tained by reduction of nitro compounds, by oxidation of amines,
or by condensations with the use of the compounds resulting
from such reduction or oxidation. Unless otherwise stated, the
following methods apply to the aromatic series only. In some
cases similar derivatives of the marsh gas series are known, but
usually they require different methods of preparation.
Azoxy compounds are formed by boiling nitro compounds with
a solution of caustic potash in methyl or ethyl alcohol, or with
a solution of sodium ethylate, or methylate, the alcohol acting as
the reducing agent.
2 R-NO 2 30 R N N R.
v
O
The method cannot be applied to compounds having a methyl
group para to the nitro group, because condensation to deriva-
tives of dibenzyl, C 6 H 5 CH 2 CH 2 C 6 H,, or stilbene, C 6 H 5 CH :
CHC 6 H 5 , takes place.
Azo compounds are prepared by the reduction of azoxy com-
pounds by distillation with iron filings, by the direct reduction
of nitro compounds with zinc dust and alcoholic potash, or by
the oxidation of hydrazo compounds by means of the oxygen of
the air acting on a solution in alcohol containing a little alkali.
R-N N-R O R N^N R.
O
2 R_NO 2 40 = R N=N R.
R_NH NH R -f O = R N=N R + H 2 6.
Aminoazo, R N=N R. NH 2 , and hydroxyazo (usually
DIAZO, HYDRAZO, NITROSO, ETC. 245
called in German text-books "oxyazo"), R N=N R OH,
compounds are formed by the condensation of diazonium
compounds, with amines or phenols. As the condensation
takes place usually in neutral, or slightly acid solutions, but
does, not. as a rule, occur in either strongly alkaline or strong-
ly acid solutions, Bamberger supposes the reaction to take
place between the diazonium hydroxide and the other compound.
/Ber., 28, 444.)
R N = X OH + H R NH 2 ==
R_N=N R NH 2 + H 2 O.
This kind of condensation takes place most readily with ter-
tiary amines, and with primary metadiamines. Primary and
secondary amines, on the other hand, condense in acetic acid
solutions, with the formation of diazoamino compounds.
R_N=N OH + R NH 2 = R N=N NHR + H 2 O.
These diazoamino compounds, when allowed to stand with
cold dilute hydrochloric acid, or when warmed with the hydro-
chloride of the amine, dissolved in the free amine, usually pass
over into the corresponding aminoazo compound ; e.g. :
C 6 H 5 N=N NHC 6 H 5 > C 6 H 5 N= N-C 6 H 4 NH 2 .
Diazoamino benzene Aminoazobenzene
This combination ("Kuppelung") of diazonium compounds
with amines and phenols, and the transformation of diazoamino
into aminoazo compounds, are of great technical importance. O.
N. Witt has pointed out that dye-stuffs must have two character-
istics; they must have a color group ("chromophore"), e.g., the
azo, or nitio group, and they must also have a salt- forming
group, ("auxochrome"), e.g., hydroxyl, or the amino group,
which will enable the substance to combine with the fibei
in dyeing. The azo compounds are all of them colored, but only
those of them which contain some "auxochrome" group as well
can be used in dyeing.
All organic coloring matters are changed to colorless com-
pounds by reduction. These colorless compounds have received
the general name of "leuco" compounds (see p. 241 also)
("Leukoverbindungen," from Greek Aev*os. white). The leuco
246 ORGANIC CHEMISTRY
compounds corresponding to the azo compounds are the hydrazo
compounds. These may be prepared from the azo compounds
by reduction with alcoholic ammonium sulphide, or with zinc
dust and alcoholic potash or soda. They may also be prepared
by direct reduction of nitro compounds with zinc dust and al-
coholic potash.
R_N=N R + 2H = R_NH NH R.
2 R NO a + loH R_NH NH R + 4H 2 O.
Diazonium compounds are formed by the action of nitrous
acid on amines in acid solutions.
RNH S HC1 + HNO, == R N = N +- 2H 2 O.
I
Cl
On account of their instability, diazonium compounds are not
usually separated, but are used for synthetical purposes im-
mediately after preparation. Several illustrations of such use
have already been given. (See pp. 702, 131, 201.)
Hydrazines are prepared by the reduction of diazonium com-
pounds with stannous chloride, with acid sodium sulphite, or with
acid sodium sulphite, zinc dust and acetic acid, followed by the
decomposition of the resulting sulphonic acid with hydrochloric
acid.
R - N = N -f 2SnCl 2 + 4HC1 R NH NH. > HCl-h2SnCl 4 .
I
Cl
R N = N + HNaSO, R N N SO s Na + HC1.
I
Cl
R_N=N SO 3 Na + 2H = R NH NH SO 3 Na.
R_NH NH SO 3 Na + HC1 + H O =
R NH NH 2 HC1 + NaHSO 4 .
Hydrazones are formed by the condensation of hydrazines
with aldehydes or ketones, usually in neutral or acetic acid so-
lution.
R \ / R
R _NH NH.+ >CO = R-NH N C< + H,O.
R/ \R
DIAZO, HYDRA2O, NITROSO, ETC. 247
Hydrazones are also formed by the condensation of diazo-
nium compounds with substances containing a methylene group
between two carboxyl groups. Owing to a different view of the
structure of these compounds, which prevailed before they had
been fully studied, they are frequently called azo compounds.
C 6 H 5 N = NOH + CH./
\COAH,
OH H
C,H 5 NH N C CO 2 C 2 H 5 =
COAH,
/C0 2 C 2 H 5
H NH N == C<
\COH
C 6 H 5 NH N == C< H f O.
i^i**i
Hydrazone of mesoxalic acid
On the supposition that the structure was represented by the
/CO.C.H,
formula C 6 H S N=NCH< , this was called ben-
N CO,C,H,
zenazomalonic ester, a name still used.
Hydrazides are formed by the condensation of hydrazines,
with compounds containing hydroxyl, the condensation taking
place readily only when the hydroxyl is more or less acid in its
properties.
R NH NH X
RNH -NH 2 + RCOOH >C = O + H 2 O.
R/
The name is given from the analogy with amides.
Osazones are formed by the action of an excess of phenyl hy-
j
' CHOH
drazine on substances containing the group \ . A part of
CO
I
the phenyl hydrazine combines at once to form a hydrazone, a
second part oxidizes the alcoholic group to a ketonic or aide-
248 ORGANIC CHEMISTRY
hyde group, and the latter reacts with more of the hydrazine.
I
C = N NHC 6 H 5
giving finally the group, | . The osazones
C = N NHC 6 H,
I
have been of especial importance in the study of sugars.
120. Preparation of a Hydrazo Compound. Hydrazobenzene,
C 6 H 5 NH NH C 6 H 5 .
Literature Hofmann : Jahresb., 1863, 424; Alexejew: Ztschr. Chem.,
1867, 33 ; 1868, 497 ; E. Erdmann : Ztschr. angew. Chem., 1893, 163.
30 grams nitrobenzene.
200 cc. alcohol.
40 cc. sodium hydroxide (3 cc. - - i gram).
45 grams zinc dust.
Put in a 500 cc. flask 200 cc. of alcohol, 30 grams of nitro-
benzene, and 40 cc. of a solution of caustic soda (3 cc = i
gram). Heat on a water-bath to about 75, putting in the
mouth of the flask a cork hearing a tube to act as an air con-
denser. Add a small amount of zinc dust, shake and add more,
in small portions, till the reaction begins. If the action becomes
violent, check it by dipping the flask in cold water. Continue
the warming and addition of zinc dust till the solution becomes
nearly colorless. Filter hot on a plate, cool quickly, filter off
the hydrazobenzene as rapidly as possible, wash with a little
alcohol, transfer it to a flask and add at once some alcohol con-
taining a little ammonium sulphide to prevent oxidation. Boil
the residue of zinc dust with the mother-liquors, filter and
separate the hydrazobenzene as before, and repeat a third time.
Then recrystallize the whole from hot alcohol containing am-
monium sulphide,, working as rapidly as possible, to prevent oxi-
dation, and finally dry the product in a vacuum desiccator, over
sulphuric acid. In recrystallizing, water may be added to the
hot, filtered alcoholic solution till it begins to be turbid, to cause
the more complete separation of the hydrazobenzene, and the
product may be washed with dilute, instead of pure alcohol. It
may also be crystallized from ligrom. Yield 19 to 20 grams.
DIAZO, HYDRAZO, NITROSO, ETC. 249
Hydrazobenzene crystallizes in colorless leaflets, which melt at
131. It is easily soluble ; n alcohol and ether, almost insoluble
in water. It is very easily converted into azobenzene, even by
the oxygen of the air. By warming with hydrochloric acid, it is
converted into benzidine, NH 2 C 6 H 4 C 6 H 4 NH 2 . It is de-
composed by heat into azobenzene and aniline.
121. Preparation of an Azo Compound. Azobenzene,
C 6 H 5 N=N C 6 H 5 .
Literature Mitscherlich : Ann., 12, 3ii;-Zinin: J. prakt. Chem., 36,
93, (1845) ; Claus: Ber., 8, 37; Griess : Ibid, 9, 132; Frankland and Louis:
J. Chem. Soc., 37, 560, (1880); Spiegel: Ber., 18, 1481 ; Mills: J. Chem.
Soc., 65, 51, (1894}: Steromeric forms, Gortner and Gortner : J. Am.
Chem. Soc., 32, 1294.
10 grams hydrazobenzene.
170 cc. alcohol.
1 cc. sodium hydroxide (3 cc. = i gram).
Put in a 300 cc. flask 10 grams of hydrazobenzene, 170 cc. of
alcohol, and i cc. of a solution of caustic soda. Close the flask
with a stopper bearing an upright condenser, and a glass tube
leading nearly to the bottom of the flask. Heat on a water-bath
and draw or force through the solution a slow current of air
for three to four hours. Filter, if necessary, distil off most of
the alcohol and allow the azo-benzene to crystallize after adding
a little water. Yield 7 to 8 grams.
Azobenzene crystallizes in red plates, which melt at 68. It
boils without decomposition at 295. It is soluble in 12 parts of
alcohol at 16.
122. Preparation of a Diazonium Compound. Benzene diazo-
nium chloride, C 6 H 5 N = N.
Cl
Literature. Griess : Ann., 113, 201; "7, i; "i, 257; i37 39; Ber.,
24, R., 1007; V .Meyer and Ambiihl : Ibid, 8, 1073; Knoevenagel: Ibid, *3,
2994; Hausser and Miiller : Bull. soc. chim. [3], 9, 353, (1893).
2 grams aniline hydrochloridei
8 cc. alcohol.
2 cc. (1.8 grams) amyl nitrite, or
1.3 cc. (1.23 grams) ethyl nitrite.
250 ORGANIC CHEMISTRY
Dissolve 2 grams of aniline hydrochloride in 8 cc. of abso-
lute alcohol in a test-tube. Cool with ice-water, add a drop of
concentrated hydrochloric acid, and then very slowly, with cool-
and and stirring, 2 cc. of amyl nitrite, or 1.3 cc. of ethyl nitrite. 1
Allow to stand in ice-water for a short time, and then filter off
the benzene diazonium chloride and wash it with a very little
alcohol, containing a 1'ttle hydrochloric acid, and with ether.
Separate into several portions and dry on filter-paper, in the
air. On account of the explosive character, the portions dried
should not exceed 0.1-0.2 gram each.
Small portions may be warmed with water, alcohol, or con-
centrated hydrochloric acid, to illustrate the decompositions of
the substance, but for most purposes of synthesis, the free di-
azonium compounds, or salts, are not prepared. See pp. 70,
131, 201.
123. Preparation of an Amino-azo Compound through the Di-
azoamino Compound. />-Aminoazobenzene,
/N-N-C.H, (i)
C 6 H/
X NH 2 (4)
Literature Griess : Ann., 121, 258; Staedel and Bauer: Ber., 19, 1952;
Niementowski and Roszkowski : Z. physik. Chem., 22, 145.
50 cc. aniline.
60 cc. concentrated hydrochloric acid.
13 grams aniline hydrochloride.
200 cc. water.
3.5 grams sodium nitrite.
17.5 cc. water.
10 grams crystallized sodium acetate.
5 grams diazoaminobenzene.
15 grams aniline.
3 grams aniline hydrochloride.
i Ethyl nitrite may be prepared a* follows: Prepare a solution of 10 grams of sodium
nitrite in 50 cc. of water and 5 cc. of alcohol, and a second solution of 5 cc. of concentrated
sulphuric acid, 50 cc. of water and 5 cc. of alcnhol. Cool each to o, and add the acid solu-
tion to the nitrite solution, with a pipette, which is inserted beneath the surface of the
liquid, cooline thoroughly. After a few minutes, separate the ethyl nitrite, which rises
to the top of the liquid, using a cold separatory funnel. Keep the nitrite in a tube, sur-
rounded with ice. It boils at 17. If larger quantities of the nitrite are desired, the solu-
tions may be prepared in the proportions given, and the nitrite solution put in a flask or
distilling bulb, connected with a condenser, fed with ice-water. The solutions should be
at 2o -2.s. On running the acid solution in slowlv, the ethyl nitrite will distil over, and
may be collected in a receiver, surrounded with ice. (Wallach and Otto: Ann., 053, 251.)
DIAZO, HYDRAZO, NITROSO, ETC. 251
Prepare some aniline hydrochloride by dissolving 50 cc. of
aniline in 6 cc. of concentrated hydrochloric acid, cooling thor-
oughly, filtering with a plate on a hardened filter, and drying on
the water-bath.
Dissolve 13 grams of the aniline chloride in 200 cc. of water,
bring the temperature to 25, and add, with stirring, 3.5 grams
of sodium nitrite, dissolved in 17.5 cc. of water. Keep the tem-
perature at 27-3O by cooling, if necessary. Add, at once, a
previously prepared solution of 10 grams of crystallized sodium
acetate, stir thoroughly and allow the whole to stand for 15
minutes. Filter off the diazoaminobenzene, wash and dry in
vacuo over sulphuric acid. The yield is 9 to 10 grams. To
obtain a pure, light yellow product it is best to dissolve immed-
iately, without drying, in ligroin, on the steam-bath, pour off
from the water and cool the ligroin solution till crystallization is
complete.
Dissolve 5 grams of the dry diazoaminobenzene in 15 cc. of
aniline, in a small flask, add 3 grams of dry, powdered aniline
hydrochloride, warm in a water-bath at 40, for an hour, and al-
low the mass to stand for a day, or until the solution no longer
evolves nitrogen when a small portion is warmed with alcohol
and hydrochloric acid. Add 40 cc. of hydrochloric acid (sp. gr.
i.io), cool, filter, and wash with dilute hydrochloric acid. Dis-
solve the hydrochloride of the aminoazobenzene in about 500 cc.
of hot water, adding enough hydrochloric acid to prevent hy-
drolysis but not more. Filter, if necessary, and add 20 to 25 cc.
of concentrated hydrochloric acid. On cooling, the hydrochlo-
ride will separate almost completely in crystalline form. Filter,
wash with dilute acid, and dry.
If the free aminoazobenzene is desired, it can be obtained by
warming the chloride with twice its weight of alcohol, and adding
concentrated ammonia till it dissolves. On further addition of
water, the base separates in orange-yellow leaflets, which may
be recrystallized from benzene. Yield of the chloride about
4^ grams.
^-Aminoazobenzene crystallizes in orange-yellow, rhombic
prisms, which melt at 127, and boil without decomposition at
252 ORGANIC CHEMISTRY
360. It is almost insoluble in water, easily soluble in alcohol
and ether. It is reduced by tin and hydrochloric acid to aniline
and paraphenylenediamine. The chloride is hydrolyzed by water
It is known as aniline yellow, and in sb'ghtly acid solution colors
wool and silk intensely yellow.
Diazoaminobenzene melts at 98, and is slightly explosive.
124. Preparation of an Azo Compound by the Combination
of a Diazonium Compound with an Amine. />-Sulphobenzene-
azo-a-napthylamine,
SO S H NH,
(4)-Sulphobenzene-azo~(4)-amino-( i ) -'naphthalene.
Literature Griess : Ber., 12, 427.
5 grams sulphanilic acid.
10 cc. sodium hydroxide (10 per cent.).
200 cc. water.
10 cc. hydrochloric acid (sp. gr. i.i).
1.7 grams sodium nitrite.
8.5 cc. water.
3.5 grams a-naphthylamine.
6 cc. hydrochloric acid (sp. gr. i.i).
200 cc. water.
Dissolve 5 grams of sulphanilic acid in 10 cc. of sodium hy-
droxide and 20 cc. of water, by warming in a flask. Cool, di-
lute to about 200 cc., add 10 cc. of hydrochloric acid (i.i) and
then 1.7 grams of sodium nitrite dissolved in 8.5 cc. of water.
Dissolve 3.5 grams of a-naphthylamine in 6 cc. of hydrochloric
acid and 200 cc. of hot water. Cool, and add the solution of
paradiazonium benzene sulphonic acid. Mix thoroughly by
UIAZO, HYDRAZO, NITROSO, ETC. 253
pouring from one beaker to another and back several times.
Allow to stand for several hours, then heat on the water-bath, or
over the free flame, till the precipitate becomes crystalline, and
much less voluminous. Filter hot, and wash.
a-Naphthylamine-azobenzene-/>-sulphonic acid crystallizes in
microscopic needles of a dark violet color. It is almost insolu-
ble, even in boiling water, and is also very difficultly soluble in
alcohol. The dilute solutions are of a bright red or pink color,
and, since the compound is formed quantitatively when nitrous
acid acts on an excess of an acid solution containing sulphanilic
acid and a-naphthylamine, it is often used for the determination
of nitrites in potable water.
Since the substance is a sulphonic acid, it dissolves to clear
orange-red solutions in very dilute solutions of caustic soda, or
ammonia, but the addition of more sodium hydroxide to such
solutions, even if quite dilute, will cause the precipitation of the
red, crystalline, sodium salt, C 16 H 12 N 3 SO 3 Na.
125. Preparation of an Azo Compound by Coupling a Diazo-
nium Compound with an Amine. Helianthine (Methyl orange,
Sodium salt of 4,4-Dimethylaminoazobenzene sulphonic acid).
(CB 3 ) 2 NC 6 H 4 N=N C a H 4 SO 3 Na.
Literature Griess : Ber., 10, 258 ; Theory of indicators, Kremann : Z.
anorg. Chem., 33> 87 ; Bredig : Z. anorg. Chem., 34 -202 ; Stieglitz : J. Am.
Chem. Soc., 25, 1112: Veley: Z. phys. Ch., 57 148; A. A. Noyes: J. Am.
Chem. Soc., 3 2 i 815; Preparation by the sulphonation of dimethylamino-
azobenzene, Nolting: Ber., 20, 2996.
Solution of diazobenzene sulphonic acid.
15 grams ice.
10 cc. sodium hydroxide (10 per cent.).
3 grams dimethyl aniline.
\y 2 grams glacial acetic acid.
3 grams sodium hydroxide.
15 cc. water.
Prepare a solution of ^-diazobenzene sulphonic acid as de-
scribed in the preceding preparation. Add 15 grams of ice and
10 cc. of sodium hydroxide, (10 per cent), then, at once, a mix-
254 ORGANIC CHEMISTRY
ture of 3 grams of dimethyl aniline and 1^2 grams of glacial
acetic acid. After 5-10 minutes add 10 cc. of a solution of so-
dium hydroxide (3 cc. = I gram). Filter on a hardened filter,
suck dry and recrystallize the sodium salt (methyl orange)
from water.
If anthranilic acid is used instead of sulphanilic acid for this
preparation, methyl red, (CH 3 ) 2 N.C 6 H 4 N=N C 6 H 4 CO 2 H
will be obtained. It is a valuable indicator for weak bases. (Ber.,
40, 2698.)
126. Preparation of a Hydrazine. Phenyl hydrazine,
C 6 H 6 NHNH 2 .
Literature E. Fischer: Ann., 190, 67; Ber., 17, 572; V. Meyer, u.
Lecco: Ibid, 16, 2976; Reychler: Ibid, 20, 2463; Overtoil: Ibid, 26, 19;
Altschul: Ibid, 25, 1849.
18.6 grams aniline.
1 60 cc. hydrochloric acid (sp. gr. 1.19).
14 grams sodium nitrite.
70 cc. water.
50 grams tin or 120 grams stannous chloride.
150 cc. hydrochloric acid (sp. gr. 1.19).
40 cc. sodium hydroxide (3 cc. = I gram).
Prepare a solution of stannous chloride by dissolving 50 grams
of feathered tin in 150 cc. of concentrated hydrochloric acid
or by dissolving 120 grams of crystallized stannous chloride in
100 cc. of concentrated hydrochloric acid. Add 18.6 grams of
aniline (i mol.) to 100 cc. of concentrated hydrochloric acid,
stirring vigorously. Set the beaker in ice-water, or a freezing
mixture, and when the temperature has fallen nearly to o, add
150 grams of ice, and then, from a drop funnel, drawn to a
narrow tube at the end, or having a narrow tube attached, and
dipping nearly to the bottom of the solution, add slowly and with
constant stirring, a cold solution of 14 grams (i mol.) of sodium
nitrite in 70 cc. of water. The temperature should not rise above
5. When all has been added, the solution, after standing two
minutes, should react for nitrous acid, when a drop is diluted
DIAZO, HYDRAZO, NITROSO, ETC. 255
and tested with stacch potassium iodide paper. If it does not, a
little more sodium nitrite must be added, using the least possible
excess. As soon as possible, add slowly, with stirring, the solution
of stannous chloride, which must, meanwhile, have been cooled
to o, or below. Add, if necessary, more ice, to keep the tem-
perature below o during the addition of the stannous chlo-
ride. Stir very thoroughly, and allow to stand for an hour.
Filter off the hydrochloride of the phenyl hydrazine, which
separates, suck and press it as free as possible from the mother-
liquors, and wash once with a small amount of dilute hydro-
chloric acid. Evaporate the nitrate to about 150 cc.> best
in a large beaker heated over a free flame on wire gauze
Cool, and separate the hydrochloride of the phenyl hydra-
zine, which crystallizes, as before. Dissolve the hydrochlo-
ride in a small amount of warm water, add an excess of a
strong solution of sodium hydroxide, cool, collect the phenyl
hydrazine with a little ether, separate, distil off the ether, dry by
allowing to stand in vacuo over sulphuric acid, or dry with fused
caustic potash, pour off and distil, best under diminished pres-
sure. Some- ammonia is formed during the distillation, which
may be removed by allowing the product to stand over sulphuric
acid. The phenyl hydrazine may be further purified by a second
distillation, or by allowing it to solidify at a low temperature,
and pouring off the liquid portion. Yield, about 18 grams.
Phenyl hydrazine boils at 242, and solidifies at a low tem-
perature, melting at 19. Its specific gravity is 1.097, at 2 3-
It is a violent poison. On adding a solution of phenyl hydrazine
acetate to a hot solution of copper sulphate, it is oxidized with
the formation of benzene. With aldehydes, ketones, and sugars,
phenyl hydrazine gives characteristic condensation products. See
PP. 89, 191.
127. Preparation of a Derivative of Hydroxylamine by the Elec-
trolytic Reduction of a Nitro Compound. /?-Phenylhydroxylamine,
C 6 H 5 NHOH.
Literature Brand: Ber., 38, 3077; Bamberger : Ber., 27, 1347, 1548;
Wohl : Ber., 28, R, 1079 ; Apparatus for electrolytic reduction, Brand :
Elektro-Chemische Reduktion organische Nitroverbindungen und ver-
256 ORGANIC CHEMISTRY
wandter Verbindungen ; Ahren's Sammlungen, 13, 51; Elbs : Uebungsbsp.
elektrolyt. Darst. chem. Praparate, Bredt : Ann., 366, 13.
Dilute sulphuric acid (1:20 by volume).
50 grams nitrobenzene.
20 grams sodium acetate.
15 cc. glacial acetic acid.
350 cc. water.
Wind a small lead pipe around a porous cell having a capacity,
of 750 cc. and place this within a battery jar or porcelain beaker
just wide enough to contain it. The space between the jar and
porous cell is to be filled with dilute sulphuric acid ( i :2O by
volume). The. lead pipe serves as anode and the whole ap-
paratus is kept cool by passing cold water through it. For
cathode a piece of nickel gauze with a surface on one side of
3 or 4 square decimeters is used. This is bent in such a man-
ner that an efficient mechanical stirrer (27, p. 76) can play within
it in the porous cup. Place in the porous cell 50 grams of nitro-
benzene, 20 grams of sodium acetate, 15 cc. of glacial acetic acid
and 350 cc. of water. This mixture must be kept thoroughly
stirred during the passage of the current. A current of 6 to 10
amperes, or of 2 to 3 amperes per square decimeter of cathode
surface should be used. The voltage required will depend on
the resistance but 10 to 12 volts should be enough. The cur-
rent is best supplied by a storage battery, if available. No hy-
drogen will appear at the cathode till the theoretical quantity
of electricity has been used and the current should be broken
soon after that point has been reached. One ampere of elec-
tricity will furnish 0.000606 gram of hydrogen per minute.
Filter the cathode liquid, wash out the porous cup with a little
warm water and add to the united filtrate clean, finely powdered
salt nearly to saturation. The /?-phenylhydroxylamine crystal-
lizes in long, silky, colorless needles which melt at 81. It may
be recrystallized from ligroin. Yield 25 to 30 grams. Care
must be taken not to bring solutions of phenylhydroxylamine in
contact with the skin as it causes on some people painful irrita-
tion and swelling.
Chapter XV
SULPHUR COMPOUNDS
In the aliphatic series sulphonic acids are obtained by the
oxidation of mercaptans (sulphur alcohols), with nitric acid, or
with potassium permanganate.
RSH + 3 = R S0 2 .OH.
They are also formed by heating the sodium salt of an acid
ester of sulphuric acid with sodium sulphite in concentrated so-
lution at a temperature of i io-i2o.( Mayer : Ber., 23, 909).
R O SO 2 O Na + Na 2 SO 3 = R SO 2 ONa + Na 2 SO 4 .
Fatty acids react with sulphur trioxide and their anhy-
drides with sulphuric acid, or with the chloride of sulphuric acid
/Cl
SO./ , to form sulphonic acids, which contain both sulphonic
X)H
and carboxyl groups, and are bibasic. The sulphonic group usually
combines with the a-carbon atom.
In the aromatic series sulphonic acids are almost exclusively
prepared by the action of sulphuric acid, sulphur trioxide, the
fuming acid or the chloride of the acid on hydrocarbons and
their derivatives. The sulphonic group usually enters into the
para or ortho position with regard to NH 2 , OH, CH 3 , OR, Cl,
Br, and I, but in the meta position with regard to CO 2 H, SO,H,
COH, COCH 3 , CN, CC1 S , or NO,. As with nitration, homo-
logues of benzene are more easily sulphonated than benzene
itself. The strength of the acid to be used, and the temperature
vary with different cases, and must be established by trial with
small amounts, or by a consideration of the conduct of analogous
compounds.
RH + H 2 SO 4 = R SO 2 OH + H 2 O
RH + SO,HC1 = RSOoCl + H 2 6.
The sulphonic acids are, in most cases, easily soluble in water,
and as a large excess of sulphuric acid must be used for their
17
258 ORGANIC CHEMISTRY
preparation, it is usually- necessary to separate the acids after
dilution with water. Two methods are commonly used. The
older method and the one almost universally applicable, consists
in neutralizing the diluted solution with calcium carbonate, or
barium carbonate, and filtering from the insoluble sulphates, the
calcium and barium salts of the sulphonic acids being usually
soluble in water. From these salts the sodium or potassium salts
can then be prepared, by use of sodium or potassium carbonate.
The second method consists in saturating the diluted solution
with salt, which will, in many cases, cause the precipitation of the
sodium salt, even in cases where the latter is comparatively easily
soluble in pure water (see p. 159 and 28, p. 79).
Sulphonium compounds are prepared by treating alkyl sul-
phides with alkyl iodides, or by treating metallic sulphides with
an excess of alkyl iodide.
R 2 S + RI = R 3 SI.
R \
Na 2 S + 3RI = R SI + aNal.
R/
The sulphonium hydroxide can be prepared from the iodides,
or other halogen salts, by treatment with silver oxide and water.
These hydroxides are strong bases, resembling the quaternary
ammonium hydroxides, and the iodoso and iodonium compounds.
The preparation of benzene sulphonic acid and the sulphone-
chloride and amide has been given in a previous chapter, (p.
159).
128. Preparation of a Sulphonic Acid of an Amine. Sulpha-
/NH 2 (i)
nilicacid, C 6 H 4 ^ . (Paraamino-sulphobenzene.)
\S0 2 OH (4)
Literature Gerhardt: Ann., 60, 310; Buckton, Hofmann: Ibid, 100,
163; Limpricht: Ibid, *77, 80; Laar: Ber., 14* 1933; Schmidt: Ann., 120,
132; Winther: Ber., 13, 1941.
30 grams aniline.
90 grams (50 cc.) concentrated sulphuric acid.
Put 90 grams of concentrated sulphuric acid in a small flask,
add in small portions, with shaking, 30 grams (30 cc.) of aniline,
SULPHUR COMPOUNDS 259
and heat in an oil-bath at i8o-i9O for four to five hours, or
until a drop of the solution, after diluting, and adding caustic
soda, shows no separation of aniline. Allow to cool, pour into
250 cc. of cold water, cool, filter, and wash. Recrystallize from
hot water, adding a little bone-black: Yield 30-35 grams.
Sulphanilic acid crystallizes with two molecules of water, in
rhombic plates, which effloresce readily. It dissolves in 166 parts
of water at 10. It carbonizes on heating to 28o-3OO. It
xSO 3 Na
forms no salts with acids. The sodium salt, C 6 H 4 ^
2H 2 O, and the barium salt, j C 6 H 4 < | Ba -f
X
r /so 3
H
NHJ
crystallize well.
Sulphanilic acid is used in water analysis for the estima-
tion of nitrites (see 124, p. 252). The sulphonic derivatives of
amines are of great technical importance, since the sulphonic
group furnishes the "auxochrome" group necessary for dyestufrs
,KH 2 (i)
(see p. 245). Sulphanilic acid, metanilic acid, C 6 H 4 preparation from
ethylene bromide, 49.
Acetylene tetrabromide 48,
Acetyl group, oxidation of, 98, 107.
Acetylides, 48, 49, 50.
Acid amides, converted into amines,
218, 234.
Acid chloride, a ketone by conden-
sation of, 101; preparation of, 144,
148.
Acid decomposition o f acetic ester,
112, 174; of 0-ketonic acids, 176*
196.
Acids, chlorides of, 144; decomposi-
tion of dibasic, 114; derivatives of,
144; formation of bibasic, 107;
from a halogen derivative of a hy-
drocarbon, 139; halogen deriva-
tives of, 196, 203; identification,
266; preparation, 106; preparation
by decomposition of bibasic acids,
115* preparation by oxidation of
an alcohol, 116; preparation from
an amine, 108, 131 preparation
from esters or glucosides, 114, 121;
preparation of a bromine deriva-
tive of an, 203; reduced to hydro-
carbons, 40; unsaturated, reduc-
tion of, i34i 136.
Acid sodium sulphite, double com-
pounds with, 59 ; preparation, 97.
Acrolein, 70.
Active forms of mandelic acid, 169.
Acyl anthranilic nitrile, preparation
of a quinazoline from an, 239.
Acyl derivative O f an amine, 157; of
a hydroxy acid, 156; of an amino
acid, preparation, 232.
2 7 6
INDEX
Alcohol, absolute, 67; by Barbier-
Grignard synthesis, 66, 745 from
aromatic aldehyde by potassium
hydroxide, 72; from glucose or
fructose, 185 ; from saponification
of an ester, 152; preparation of an
acid by oxidation of, n6; specific
gravity of, 3 2 J unsaturated, 69; 64;
from amines, 64, 7; identification,
268; oxidation of, 89, 106, n6;
preparation of hydrocarbon from,
45J reduced to hydrocarbons, 40.
Aldehyde ammonia, 91.
Aldehyde, condensation with amine
to leuco base, 241; preparation of
from an a-hydroxy acid, 166; 86;
by Etard's method, 86; by the
Barbier-Grignard reaction, 67 ;
from a monochlor derivative of
an aromatic hydrocarbon, 96; from
glyoxylic acids , 88 ; from a-hy-
droxy acids, 87 ; from nitro com-
pounds, 87; identification, 271;
oxidation of, 106; reactions of,
88; test for, 91.
Alicyclic compounds, 40.
Aliphatic series, nitro compounds of
the, 209.
Alizarin, 78; reduction to anthracene,
61.
Alkaloids, identification, 272.
Alkyl dithiocarbonic acid from a pri-
mary amine, 268.
Alkyl-sulphonamides, 160.
Alloxan from uric acid, 163.
Allyl alcohol, 69, 115.
Allyl amine, 218.
Auminium chloride, o-benzoylbenzoic
acid by means of, 104; condensa-
tion by means of, 38, 58, 101, 104;
preparation, 59J synthesis of hy-
drocarbons by use of, 58.
Aluminium hydroxide, use in clear-
ing solution, 231-
Amalgam, magnesium, 113; sodium,
i35-
Amide, from an acid, 156; from the
chloride of an acid, 145, 158, 260;
from ammonium salts of acids,
145; from cyanides, 108; from es-
ters, 146; identification, 266.
Amine, dimethyl and diethyl from
/>-nitrosodimethyl- or diethylani-
line, 220; acid amides converted
into, 218, 234; acid from, 108, I3 1 ;
acyl derivative of, I 57> converted
into alcohols, 64, 7J aromatic con-
verted into hydrocarbons, 41 ; aro-
matic, from phenols, 219 ; by the
reduction of a cyanide, 272; by re-
duction of a nitro compound, 220;
by reduction of hydrazones, 218;
by reduction of oximes, 218, 226;
for dyes, 220 ; formation of sec-
ondary and tertiary, 217; from an
alkyl derivative of aniline, 224;
from an oxime, 226; from Marsh
gas series, 217; halogen deriva-
tives from the, 195, 201; identifi-
cation, 267 ; nitriles reduced to,
218; preparation, 217; preparation
with' phthalimide, 217; preparation
by use of hexamethylene amine,
218, 229; separation of primary,
secondary and tertiary, 160 ; sul-
phonic acid of, 258.
Aminoacetate, copper, 231.
Aminoacetic acid, secondary and ter-
tiary, 232; hippuric acid from, 232.
a-Amino acid from a-amino nitrile,
220, 233.
Amino acid from a halogen deriva-
tive of an acid, 231; preparation
of an acyl derivative of an, 232 ;
from the half amide of a bibasic
acid, 234.
Aminoazobenzene, 245, 250, 251.
INDEX
277
Aminoazo compounds, 244; prepara-
tion of through the diazoamino
compound, 250.
2-Aminobenzoic acid, 234.
Aminoethanoic acid, 231.
i^Aminoethylphen, 101.
i 2 -Aminoethylphen, 227.
Amino group, elimination of, 212; re-
placement by bromine, 201; re-
placement by cyanogen, 13* re-
placement by hydrogen, 41, 212;
replacement by hydroxyl, 7 re-
placement by the ethoxy group.
41.
a-Aminoisobutyric acid, 233.
Aminomethylphen, 229.
Aminonaphthalene by reduction of
a-nitronaphthalene, 212.
a-Amino nitrile from an aldehyde or
ketone, 220, 233.
/>-Amino-o-nitrotoluene, 214, 221.
2-Aminopropane, 226.
/j-Amino-sulphobenzene, 258.
Ammonia, distillation of, 18, 19.
Ammonium acetate, 156.
Amyl alcohol, oxidation, 116.
Amyl nitrite, use to prepare a di-
azonium compound, 250.
Anesthetic, ethyl bromide as an, 198.
a- and ^-Angelica lactones, 193.
Anhydride of a bibasic acid, 150;
of an acid, 144* *49, 150.
Anhydrous keto ester from dihy-
droxy compound, 183.
Anilides, 146.
Anilinomalonic ester, 237.
Aniline, anilinomalonic ester from,
237; formation by reduction of a
phenyl hydrazone, 101 : fractional
distillation and the determination
of boiling-points, 25; hydrobro-
mide, 237; hydrochloride, 251;
preparation, 220; ^reparation of
an amine by means of, 244.
"Aniline yellow," 252.
Anisole, 83.
Anthracene, 60, 103.
Anthranilic acid, 234; by reduction
of nitrobenzoic acid, 235; prepara-
tion of indigo from, 235.
Anthraquinone, 103; from o-benzoyl-
benzoic acid, 104; sulphonic acid,
79-
i.2-Anthraquinonediol, 78.
Antifebrin, 158.
Antipyrine, 178.
Antiseptic, salicylic acid, 166.
Apparatus for determination of
boiling-points, Mulliken's, 270 ;
Smith and Menzies', 269; for dis-
tillation with steam, 71 ; for dis-
tillation under diminished pressure,
171 ; for fractional distillation, 26,
36; for melting-points, 31 ; for stir-
ring, 77J for sublimation, 80.
Aromatic acid, preparation of a nitro
derivative of an, 215.
Aromatic compounds, nitro deriva-
tives, 209.
Arsenic acid in Skraup's synthesis,
238.
Arsenic, detection in ethyl bromide,
198.
Autoclave, use for alkali fusions, 79.
Auxochrome groups, 245, 259.
Azobenzene, 249.
Azo compounds, identifications, 268;
preparation from a diazonium com-
pound, 252, 253; by reduction, 244.
Azo dyes, 259, 252.
Azotometer, calibrating. 13.
Azoxy compounds, 2/1/1
Azulmic acid, 132.
Barbier-Grignard syntheses, 65, 74,
105.
Barium, determination of in salts of
organic acids, 24,
Barium nitrate, oxidation of benzyl
chloride by, 96-
2 7 8
INDEX
Barium salts of nitro benzole acids,
129.
Barometer, correction for, 14.
Bases, indicator for weak, 254.
Bath, Volhard, 53.
Baumann-Schotten reaction, 154, 155.
Beckmann's mixture for oxidizing
alcohols, 86.
Beckmann's rearrangement, 102.
Benzalacetone, 99, 100.
Benzaldehyde, benzyl alcohol from,
72; condensation with acetone, 99J
condensation of with a methyl
group, 100; condensation to ben-
zoin, 97 J condensation with di-
methyl aniline, 242; in Perkin's
synthesis, 113, 133; mandelic acid
from, 167 ; preparation, 96.
Benzal chloride, 201.
Benzamide, 1,61.
Benzanilide, 102.
Benzenazomalonic ester, 247.
Benzene-azo-a-naphthylamine s u 1 -
phonic acid, 252.
Benzene, bromination of, 198; con-
densation of an acid chloride with,
101; condensation with phthalic an-
hydride, 104; diphenyl from, 56;
mononitro compounds of, 201; ni-
tration of, 210, 21 1 ; nitro com-
pounds of the homologues of, 209;
preparation, 50; preparation of a
diamino derivative of, 223; reduc-
tion of, 40, 5> sulphonation of,
i59'> test for, 53.
Benzene diazonium chloride, 249.
Benzene sulphonamide, 160.
Benzene sulphonechloride, 160.
Benzidine, 249.
Benzil from benzoin, 97, 98.
Benzilic acid from benzil, 98.
Benzoic acid, ;benzene_ from, 5; by
oxidation of benzyl chloride, 125,
201 ; characteristics of ortho hy-
droxy derivatives, 174; nitration
of, 216; o-sulphamide of, 260, 261.
Benzoic ethyl ester, 153.
Benzoic sulphinide, 261.
Benzoin, preparation, 97 J oxidation
to benzil, 98.
Benzonitrile, 161.
Benzo.phenone, boiling-point for coK
rection of thermometer, 102 ; pre-
paration, 101; reduction by hy-
driodic acid, 57 stereoisomerism
of oximes of, 98.
Benzoquinone, 77.
Benzoyl aminoacetic acid, 232.
o-Benzoylbenzoic acid, 103, 104.
Benzoylbromanilide, 102.
Benzoyl chloride, benzamide from,
i6i benzophenone from, 101; use
in Schotten-Baumann reaction, 104.
Benzyl acetoacetic ester, 177.
Benzyl acetone, 178.
Benzyl alcohol, from benzaldehyde,
72; from benzyl chloride, 201.
Benzyl amine, 218, 229.
Benzyl chloride, benzaldehyde from,
96; oxidation to benzoic acid, 125;
preparation, 199.
Benzyl cyanide, 228.
Bibasic acids, decomposition of, 114,
115; preparation of an ester of a,
152.
Bleaching powder, preparation of
chloroform with, 195, 206.
Boiling capillary, 125.
Boiling-points, correction of for pres-
sure, 29 ; determination with small
amounts, 269, 270; o.f carbon tetra
chloride and aniline, 25, 27.
Bromine, measurement of, 204.
Bromination, 204, 205.
Bromine derivative O f an acid, 203;
of a hydrocarbon from an aromat-
ic amine, 201; o f an ester, 205;
of the hydrocarbons, 194, 197, 198.
Bromine, test for, 265.
INDEX
279
Bromoform, 92.
/>-Bromobenzoic acid, 203.
Bromobenzoylanilide, 102.
Bromo-(2)-butanoic acid, 203.
a-Bromobutyric acid, 203.
Bromoisobutyric ester, trimethyl suc-
cinnic acid from, 112.
Bromomalonic acid, ethyl ester of,
237-
/>-Bromotoluene, preparation, 201; p-
xylene from, 55-
Bruhl's apparatus, go.
Bunsen pump, 173.
Bunsen valve, 182.
Butane, chlorination of, 194.
Butanoic acid, 119.
2-Butanone, 106.
3-Butanonic ethyl ester, 170.
i,3-Butylonephen, 178.
Butyric acid, bromination, 203; sep-
aration from propionic acid, ng,
107.
Cadaverine, synthesis of from tri-
methylene cyanide, 228.
Calcium acetate, 37.
Calcium chloride, combination of ben-
zyl alcohol with, 73; drying with,
26, 117, 127, 170, 207.
Calcium, determination of in salts
of organic acids, 24.
Calcium hypochlorite, preparation of
chloroform by, 195, 206.
Camphoronic acid, 124.
Camphor, oxidation, 123; preparation
of a hydrocarbon from, 56.
a-Camphoramidic acid, ammonium
salt of, 124, 125.
j3-Camphoramidic acid, sodium salt
of, 124, 125.
Camphoric acid by oxidation of a
cyclic ketone, 107, 122.
Camphoric anhydride, 124.
Camphoric imide, 124.
Cane-sugar, inversion, 188; levulinic
acid from, 192.
Carbamide, 158.
Carbides, hydrocarbon from, 47-
Carbohydrates, 184; complex rear-
rangements produced in, 185 ; fur-
fural from, 190 ; levulinic acid
from, 192-
Carbon compounds, analysis of, i ;
qualitative examination of, 264.
Carbon tetrachloride, fractional dis-
tillation and the determination of
boiling-points, 25.
Carbonyl chloride, urea from, 158.
Carius* method for determining halo-
gens, sulphur and phosphorus, 20.
Cellulose, 184; solution of, 189.
Chapman pump, 173.
Chloracetic acid, malonic ester from,
136; preparation of indigo from,
236.
Chloral hydrate, 183.
Chloride of lime, sodium hypochlor-
ite from, ioo.
Chloride of sulphuric acid, prepara-
tion and use in sulphonation, 260.
Chlorides of acids, 144.
Chlorination, direct of butane, 194.
Chlorine derivatives of the hydrocar-
bons, 194, 206; preparation, 200;
substitution in side chain of an
aromiatic hydrocarbon, i99> test
for, 265.
Chlorobenzoic acid, 85.
Chloroform, triphenylmethane from,
58; preparation, 206.
Chloroplatinic acid ("platinic chlo-
ride"), salts with amines, 227.
Chromic acid, oxidation with, 89,
103, 116, 1 19, 260.
Chromic anhydride, oxidation by, 103.
Chromophore group, 183, 245.
Cinnamic acid, from benzalacetone,
99; dibromide, 134; Perkin's syn-
thesis, 113, i33 135; reduction of,
134-
280
INDEX
Cinchonine salt, crystallization to
effect separation, 169.
Ciscrotonic acid, 205.
Claisen distilling bulb, 172.
Claisen researches on condensation,
109, no.
Collidine, 241.
Collidinedicarboxyllic ester, 240.
Colloidal solution, clearing of, 231.
Condensation^ by means of aluminum
chloride, 38, 58, 101, 103; by
means of zinc chloride, 142, 242;
of acetic to acetoacetic ester, 109,
i7 of acetoacetic ester with a
halogen compound, 176? of aceto-
acetic ester with itself, I75J of
acetone with benzaldehyde, 99J of
an aldehyde with the sodium salt
of an acid, 165; of an aldehyde
with itself by potassium cyanide,
97 > of a diazonium compound
with amines and phenols, 245, 250,
252.
Condensation products o f aldehydes
and ketones, 88.
Condenser, upright, 68.
Copper aminoacetate, 231.
Copper as catalyzer, 84.
Copper compounds from all deriva-
tives of acetylene, 50.
Corn cobs, furfural from, 190.
Correction for barometer, 14; of
boiling-points for pressure, 29; for
thermometer, 28.
Coupling reactions, 245.
/>-Cresol, 70.
r/^-Crotonic acid, 205.
Crystallization, fractional, 121, 129.
Cuprous bromide, 202.
Cyanacetic ester, I39; condensations
with, 112.
Cyanhydrines, 108; of glucose, 185;
preparation of a-hydroxy acid
through, 167; saponified to an ct-
hydroxy acid, 164, 167; prepara-
tion, 164.
Cyanides from amides, 161; from a
halogen derivative of a hydrocar-
bon, 139, 227; from aromatic
amines, 108, 13*1 Ladenburg meth-
od of reduction, 228; preparation
of an amine by the reduction of a,
227; saponifkation of, 107, 108,
133, 138, 140; test for, 265.
Cyclic ketones, 86.
Cyclohexane, 50.
i.4-Cyclohexanedione, 181.
Cymene from camphor, 40, 56; from
geranial, 40.
Dehydracetic acid, 174.
Density, determination of, of ethane,
42.
Determination of elements of sub-
stances, 264; of specific gravity,
32.
Dextrin, 184, 187.
Dextrosazone, 191.
Diacetyl succinic ester, 175.
Di-acetyl tartaric ethyl ester, 154.
Dialkyl-sulphonamides, 160.
/>-Diaminobenzene, 223.
Diastase, 184.
Diazoamino benzene, 251.
Diazoamino compounds, 245 ; trans-
formation into aminoazo com-
pounds, 245.
/>-Diazobenzene sulphonic acid, 253.
Diazo compounds, 244.
/>-Diazonium benzene sulphonic acid,
252.
Diazonium compounds, 246; azo com-
pound from, 250, 252; cyanide
from, 131; discussion of decompo-
sition in Sandmeyer's reaction, 202;
halogen compound from, 201; hy-
drazine from, 254; hydrocarbons
from, 41, 213; identification, 268:
phenol from, 70; preparation', 249.
Diazonium-cuprous bromide, 201.
INDEX
28l
Diazonium derivative of p. toluidine,
201.
Diazonium reaction, use in preparing
a nitro compound, 210, 212.
Dibenzalacetone, 99.
Dibenzyl, 244; from benzoin, 98.
Dibenzyl acetoacetic ester, 177.
Dibromoallyl alcohol, 70.
/7-Dibromobenzene, 198.
Dibromocinnamic acid, 134.
Dibromoethane, 44.
Diethylamine, 224.
Diethylammonium chloride, 225.
Diethyl aniline, 225.
Diethyl tartaric ester, 155.
Dihalogen substitution products, 194.
Dihydrocollidinedicarboxyllic ester,
240.
Dihydroxy acids, 65.
Dihydroxy malonic acid, ethyl ester
of, 182; from uric acid, 163; 182;
from the green oxomalonic ester,
J 83; dissociation of, 183.
Dihydroxyquinone from a sulphonic
acid, 78.
Dihydroxyterephthalic ester, 182.
Diketohexamethylene, 181.
4^4-Dimethylaminoazobenzene s u 1 -
phonic acid, sodium salt of, 253.
Dimethylaniline, condensation with
benzaldehyde, 242; condensation
with diazobenzene sulphonic acid,
253.
2,7-Dimethyl-4-hydroxyquinazoline,
239-
2,7-Dimethyl-4-ketodihydroquinazo-
line, 239.
i.4-Dimethylphen, 54.
Dimethyl sulphate, 83.
?/?-Dinitrobenzene, 211.
Dinitro compound, reduction of, 221.
Dinitrotoluene, preparation and re-
duction, 222.
Dioximes O f benzil, 98.
Diphenyl, 56.
Diphenylgycolic acid from benzil, 98.
Diphenylmethane, 57, 59.
Diphenylmethanone, 101.
Diphenylmethanonemethyllic (2) acid,
103.
Diphenyl sulphone, 159.
Dipropylketone, 119.
Distillation, fractional, 26, 30, 36, 55,
127, 157, 172, 200, 206; of wood,
34 under diminished pressure,
171; with steam, 7 X > 117, 128.
Distilling bulb, Claisen, 172; Hop-
kins, 19* Ladenburg, 172.
Drying substances, under diminished
pressure, 138; with calcium chlo-
ride, 26, 197, 117, 127, 198, 207;
with potassium hydroxide, 26, 226,
228.
Dye, amines for, 220 ; by condensa-
tion of an aldehyde, 244; azo,
245, 250, 252.
Dyestuffs, auxochrome group for,
259; characteristics, 245.
Electrolytic reduction, 136, 255; of a
nitro compound, 255.
Elements, determination, 264.
Elimination of an amino group, 212.
"Enol" form, no, 165.
Enzyme, preparation of a sugar by
action of an, 187.
Eosin, i 43 ;
Esterification, theory of, 147.
Esters, 147; acids from, 114, 121,
152; amides from, 146; from chlo-
rides of acids, 148; from a halo-
gen derivative of an acid, 136;
identification, 266; of a hydroxy
acid and an acetyl derivative,
154; preparation, I5 1 * ^2, i53>
154; preparation by condensation
by sodium ethylate, 170; saponifi-
cation of, 152.
Etard's method for aldehydes, 86.
Ethanal, 89.
Ethanediol, 75.
282
INDEX
Ethane, preparation and determina-
tion of density, 4 2 -
Ethanoic acid, ethyl ester of, 51 1-
Ethanoic anhydride, 149.
Ethanoyl chloride, 148.
Ether, dry, 82, 175; extraction of
mandelic acid with, 167; phenyl,
of salicyclic acid, 84, 105.
Ethers, 81.
Ethyl acetic ester, 151.
Ethyl alcohol, absolute, 67.
Ethyl benzoate, triphenyl carbinol
from, 74-
Ethyl aniline, 225.
Ethyl bromide, 197, 198.
Ethylene, preparation, 44-
Ethylene bromide, 44; acetylene
from, 49; ethylene cyanide from,
140; glycol from, 75-
Ethylene cyanide, conduct on re-
duction, 228 ; preparation, ' 139-
Ethylene dibromide, 44.
Ethylene glycol, 75.
Ethylene series preparation of hy-
drocarbons of, 44-
Ethyl dihydroxymalonate, priepara-
tion of, 182.
Ethyl ether, 81.
Ethyl oxomalonate, preparation of,
182.
Ethyl nitrite, preparation, 250.
Ethyl potassium sulphate, 198.
Ethyl succinic ester, 152.
Ethyl sulphuric acid, ethyl bromide
from, 198.
Ethyl zinc iodide, 62.
Extraction with ether, rules, 167,
1 68, 169.
Fat, saponification of, 121.
Fatty acids, separation of two, 119*
121 ; sulphonic acids of, 257.
Fehling's solution and its effect on
sugars, 185.
Ferric bromide, used in bromination,
194, J 99-
Ferric choride, color reaction, 166,
174-
Filtration o f a hot solution for
crystallization, 181; with a Witt
plate or Hirsch funnel, 120.
Fittig's synthesis o f hydrocarbons,
55-
Fluorescein, 142.
Formaldehyde, condensation, 113,
1 14 ; hexamethylene amine from,
228.
Formic acid, 115; from glucose, 193.
Friedel and Crafts reaction, 38; ap-
plication to phthalic anhydride,
103; benzophenone by, 101; tri-
phenylmethane by, 58.
Fractional crystallization, 130.
Fractional distillation, 26, 30, 36, 55,
172, 200, 206.
^'-Fructose, 184.
Furfural from pentoses, 185, 190;
test for, 191.
Furfuramide, 191.
Furoin, 191.
Fusel oil, oxidation, n8.
Gattermann's reaction, 195.
Germicide, iodoform, 208.
General operations, 25.
Geryk pump, 173.
Glucoheptonic acid, 185.
Glucosazone from rf-glucose and d'-
fructose, 185; preparation, 191-
rf-Glucose, 184.
Glucose, formation of levulinic acid
from, 185, 192.
Glucosides, acids from, 114.
Glutaric acid and derivatives, 145.
Glutaric ester, 112.
Glycerol, allyl alcohol from, 69; use
in preparing formic acid, "S-
Glycocoll, preparation, 231; hippuric
acid from, 232.
Glycol, ethylene, 75-
Glycolic acid, 76, 232.
Glycols, 65.
INDEX
28 3
Glyoxylic acids, aldehydes from, 88.
107.
Grignard-Barbier synthesis, 65, 74-
Guano, uric acid from, 162.
Halogen alkyls, 194.
Halogen compounds, 194; synthesis
of an acid by condensation of ace-
toacetic ester with a, 176; decom-
position with sodium ethylate, 49
from the amines, 195, 201.
Halogen derivatives, identification,
267; of acids, 196, 203.
Halogens, determination of by Car-
ius' method, 20; determination of
by Pringsheim's method, 21 ; de-
termination of by reduction with
sodium and absolute alcohol, 23;
test for, 265.
Halogen derivatives, treating, with
aqueous solution of ammonia, 217,
231.
Hell-Volhard-Zelinsky's method o f
preparation of a bromine deriva-
tive of an acid, 203.
Helianthine, 253.
Hempel column o f beads, 36.
4-Heptanone, 106, 119-
Heptylic acid, 185.
Herzfeldt's formula for determining
sucrose in pres'ence of other sug-
ars, 189.
Hexamethylene amine, use in pre-
paring amines, 218, 229.
Hexamethylene compounds trans-
formed to pentamethylene by hy-
driodic acid, 40.
Hippuric acid, 232.
Hirsch funnel, 120.
Hofmann's reaction for preparing
amines, 219, 234.
Homoanthranilic nitrile, 239.
Hydrazides, 247; formation of, 179-
Hydrazines, 246 ; preparation of
phenyl, 254.
Hydrazobenzene, 248.
Hydrazo compounds, 244; identifica-
tion, 268; preparation of a, 248-
Hydrazones, amines by reduction of,
218; formed, by condensation of
hydrazines with aldehydes or ke-
tones, 246; by condensation of
diazonium compounds, 247 ; of fur-
fural, 191 ; of mesoxalic acid, 247.
Hydriodic acid, reduction of ketones
by, 57- .
Hydrocarbon, bromine derivative,
197; bromine derivative of from
an amine, 201; by the Barbier-
Grignard reaction, 65; from car-
bides, 41, 48; from halogen com-
pounds and sodium, 54J identifica-
tion, 271 ; iodine derivative, 196;
nitration of an aromatic, 126, 210;
oxidation of, 106; preparation of,
38; preparation by reduction with
zinc dust, 60.
Hydrochloric acid, reagent, 272.
Hydrocinnamic acid, by reduction of
cinnamic acid, I34J from aceto-
acetic ester, 176.
Hydrocyanic acid, use in benzalde-
hyde, 97.
Hydrogen sodium sulphite, double
compound of aldehydes and ke-
tones, 89.
Hydrogen sulphide, reduction of a
nitro compound by, 222.
Hydrolysis of a platosan, 190.
Hydroxypropylbenzoic acid, 56.
Hydroquinone, 76.
a-Hydroxy acid from an aldehyde,
166; preparation, 108, J 65-
Hydroxy acid, preparation from a
phenol, 165; ester and acetyl de-
rivative of, 154; ortho- and para-
from phenols, 164.
Hydroxyanthraquinone from phenol
phthalein, 142.
Hydroxyazo compounds, 244.
o-Hydroxybenzoic acid, 165.
284
INDEX
/j-Hydroxybenzoic acid, 166.
Hydroxybutyric acid, 205.
Hydroxylamine, preparation of a de-
rivative of, by electrolytic reduc-
tion of a nitro compound, 255.
7-Hydroxyvaleric acid, 193.
Hypobromite, sodium, preparation of
pure, 235; use in Hofmann's reac-
tion, 236.
Hypochlorite, preparation of chloro-
form by use of, 206; action on or-
ganic compounds, 195.
Imide, camphoric, 124.
Imides f rom acids, 146 ; identifica-
tion, 266.
Immiscible solvents, 167.
Indicator for weak bases, 254.
Indigo, preparation from anthranilic
acid, 235; synthesis of, 113.
Indoxyl, 237.
Indoxylic acid, 237.
Inversion of sucrose, 185. .
Iodides, reduction of to the hydro-
carbon, 39, 42.
Iodine derivatives, 195; of a hydro-
carbon from an alcohol, methyl
iodide, 196; of a hydrocarbon,
iodoform, 207.
Iodine, test for, 265.
Iodoform, 92, 207.
lodonium compounds, 258.
lodoso compounds, 258.
Isatine, test for thiophene, 263.
Isocinnamic acid, 134.
Isocyanides, 108.
Isonitrile, formation from primary
amine, 267.
Isonitroso acetone, 93.
Isopropyl amine, 226.
Isothiocyanate, formation, 268.
Isovaleric acid, by oxidation of iso-
amyl alcohol, 106, 116.
Ketones, 86; to oxidation of alco-
hols, 98; by the Barbier-Grignard
reaction, 67 ; by Friedel and Craft's
reaction, 87, 101; from a_hydroxy
acids, 87; from nitro compounds,
87 ; identification, 271 ; oxidation of
106, 119; oxidation of cyclic, 122;
reactions of, 88 ; reduced to hy-
drocarbons, 40, 57-
Ketonic acids, 164; esters of, 165.
/3-Ketonic acids, decomposition of,
112; acid decomposition of, 178,
196.
Ketonic decomposition, 174; of ace-
toacetic ester, 112.
KnoevenageFs synthesis, 113.
Kohnlein's method of preparing hy-
drocarbons, 39.
Kolbe's synthesis, 164, 165.
Kraft's use of sulphonic acids, to
prepare ether, 81.
"Kuppelung," 245.
Lactone, angelica, 193; valero, 193.
Lactose, or milk sugar, 184.
Ladenburg's distilling bulb, 172.
Ladenburg's method of reducing cy-
anides, 227.
Law of partition for immiscible sol-
vents, 168.
Laws of substitution in aromatic
compounds, 209, 257.
Liebig's condenser, 62.
Leuco base, preparation by conden-
sation of an aldehyde, 241.
Leuco compounds, 245.
Levulinic acid from glucose, 185.
192.
Levulosazone, 191.
Liebermann's reaction for identifica-
tion of primary amines, 267.
Magnesium acetate, 121.
Magnesium bromide to purify ether,
83.
Magnesium ethylate, 113.
Malachite green, 241.
Malonic acid, 138; decomposition, 112.
Malonic ester, obtaining derivatives
of, TII; preparation, 136.
INDEX
285
Maltose, 184, 187.
Mandelic acid, 166, 167, 169.
Mannesmann tube, 79.
Manometer, 173; calibrating, 174.
Marsh gas series, amines from, 217;
nitro derivatives of hydrocarbons
of the, 209.
Melting-points, correction for, 28,
30 ; determination of, 29.
Mesoxalic acid, ethyl ester of, 182;
from alloxan, 163; hydrazone of,
247.
Metaldehyde, 91.
Metals, determination of, 24.
Metallic compounds from all deriva-
tives of acetylene, 50.
Metanilic acid, 259.
Methane, 41.
Methanoic acid, 115.
Methine group, 165.
Methyl alcohol, 197.
3-Methylbutanoic acid, 116.
3-Methyl butanol, oxidation, 116.
2-Methylbutanols, 1 18.
Methylcyanide from acetamide, 157.
Methylene-diethyl ether, 218, 230.
Methylene group, 165.
Methyl iodide, 55 ; action on phenyl-
pyrazolone, i?9J preparation, 196-
/>-Methyl-isopropylphen, 56.
/j-Methyl phenol, 70.
Methyl orange, 253.
Methyl red, 254.
Mercaptans, oxidation of, 257.
Mercuric oxide dissolved by solution
of acetamide. 157.
Mesitylene from acetone, 40.
Mesoxalic acid ester, preparation.
182.
Mesoxalic acid from uric acid, 163.
Monobenzyl acetoacetic ester, 177.
Monobromomalonic acid, ethyl ester
of, 205.
Monochloracetic acid, aminoacetic
acid from, 231; malonic ester from,
136.
Monohalogen derivatives O f saturated
hydrocarbons, I94J of the ethyl -
ene series, 195-
"Monohydrate" sulphuric acid, 216.
Monoximes of benzil, 98.
Mordants, effect on alizarin, 80.
Mulliken's apparatus for boiling-
points, 270.
Murexide reaction, 163.
Mustard oils, 268.
Naphthalene, nitration of, 212; tetra-
hydride, 40.
a-Naphthtylamine, 212.
a_Naphthylamine-azobenzene-/> - s u 1 -
phonic acid, 253.
a-Naphthylamine, condensation prod-
uct from, 252; sulphonic acids of,
259-
j3-Naphthylamine, sulphonic acids of,
259.
Nickel, preparation of finely divided
nickel, 5 1 -
Nitration, 209; of acetanilide, 223;
acetotoluide, 213; benzene, 210,
21 1 ; benzoic acid, 215; naphtha-
lene, 212; toluene, 126; toluidine,
214; urea, 94 J laws of position of
groups in, 209; preparation of a
dinitro compound by direct, 211.
Nitric acid, oxidation of benzoin
with, 98; oxidation of benzyl alco-
hol, 125.
Nitriles 147 ; formation of in Hof-
mann's reaction, 219 ; *rom amides,
161; identification, 266; reduced to
amines, 218, 229.
Nitrites, determination of in potable
waters, 212.
/j-Nitroacetanilide 223, 224.
3-Nitro-4-acetotoluide, 213, 214.
286
INDEX
Nitrobenzene, 210; azobenzene from,
248; quinoline from, 238; reduc-
tion to /3-phenylhydroxyl aminCj
256.
Nitrobenzoic acids, 216.
ra-Nitrobenzoic acid, 214, 215.
o_Nitrobenzoic acid, 126; reduction
of, 235.
/>-Nitrobenzoic acid, 126.
Nitro compounds, 209; identification,
267; primary, secondary and ter-
tiary, 210; reduction to an amine,
22O, 221.
Nitro derivative of an amine, 214;
of aromatic acid, 215.
Nitrogen compounds, derived from
amines, 244.
Nitrogen, determination of by the
"absolute" method, 9 ; determination
of by the Kjeldahl method, 18;
logarithmic table for reduction of
cc. to grams, 15; oxides, 182; test
for, 264, 265; weight of in one
cubic centimeter of the gas, 16.
a-Nitronaphthalene, 212.
Nitrophthalic acid, 212.
Nitrophenols, 210.
Nitroso compounds, 244.
/-Nitrosodiethylaniline, diethyl amine
from, 220, 225.
/>-Nitrosodimethylaniline, dimethyl
amine from, 220.
Nitrosoethyl aniline, 225.
Nitrosophenol, formation, 267.
/>-Nitrosophenol, 225.
Nitrotoluenes, 127, 128.
tw-Nitrotoluene, 212, 214.
o- or />-Nitrotoluene, oxidation by
potassium ferricyanide, 214.
3-Nitro-4-toluidine, 213, 214.
2-Nitro-4-toluidine, 215, 222.
Nitrourea, 158.
Nitrous acid, test for, 255.
"Nitrous anhydride," 214.
Oil of bitter almonds, 96.
Oleic acid, 122.
Optical isomers o f sulphonium com-
pounds, 262.
Osazone, preparation of an, 191, 247.
Oxalic acid, decomposition, 114, 115-
Oxidation o f a cyclic ketone, 122;
of an alcohol to an aldehyde, 89;
of an alcohol to an acid, 116; of,
an alcohol, to a ketone, 98; of a
side chain, 126; with a chlorate,
79; with a nitrate, 96; with nitric
acid, 98, 125; with potassium per-
manganate, 126; with sodium hy-
ipochlorite, 99 with ,sodium or
potassium pyrochromate, 77> Il6 J
with chromic anhydride, 103.
Oximes, amines by reduction of, 218,
226; from benzil, 98; from benzo-
phenone, 102 ; monobrombenzo-
phenone, and Beckmann's rear-
rangement, 102 ; preparation, 89,
93-
Oxomalonic ester, 182.
"Oxyazo" compounds, 245.
"Oxy" compounds, see hydroxy.
Palmitic acid, 122.
Paraldehyde, 91.
Pararosaniline from triphenylmeth-
ane, 59-
Partition coefficient, 167.
Penicilium Glaucum destroys levo
form to effect separation, 170.
Pentacetyl glucose, 185.
Pentamethylene compounds from
hexamethylene, 40.
2-Pentanone, 106.
Pentosans, 185.
Pentoses, formation of furfural
from, 185, 190.
Perkin's synthesis, 113, 133.
Phen, 50.
"Phenathylsaure," 176.
1 4-Phendiol, 76.
Phenethylol, 73.
Phenethylolic acid, 166.
INDEX
287
Phenmethylol, 72.
Phenolphthalein, 141, 142.
Phenols, 64; aromatic amines from,
219; from sulphonic acids, 64, 78;
hydroxy acids from, 164, 165;
identification, 268, 270; phenol
phthalein from, 141 ; preparation
of the benzoyl derivative of a, I54J
preparation through a diazonium
compound, 7 reduced to hydro-
carbons, 40, 61-
Phen-3-propanoic acid, 134, 176.
Phenyl benzoate, 154.
Phenyl cyanide, 161; conduct on re-
duction, 228.
i -Phenyl-2,3-dimethyl-pyrazolone, 178.
/>-Phenylenediamine, 223.
Phenyl ether o f salicylic acid, 84.
w-Phenyl-ethyl-amine, 227; hydro-
chloride, 229.
Phenylglycine-o-carboxylic acid, 236.
Phenyl hydrazine, hydrazones and
osazones from, 247; hydrazone
from, 100; preparation, 254; 89,
100.
-Phenylhydroxylamine, 255.
Phenylmethylcarbinamine, 101.
Phenyl methyl carbinol, 73.
Phenyl methyl ether, 83.
i-Phenyl-2,3-dimethyl-pyrazolone, 178.
i-Phenyl-3-methylpyrazolone, 179.
Phenyl propiolic acid, 134.
Phenyl sodium carbonate, 164.
Phenyl sulphonamide, 159.
Phenyl sulphonechloride, preparation,
159; use in separating amines, 160.
Phenyl xanthenol, 105.
Phosgene, urea from, 158.
Phosphorus, determination of by Car-
ius' method, 20.
Phosphorus oxybromide, 204; action
on acids and salts, decomposition,
205 ; to prepare succinic anhydride,
150.
Phosphorus pentachloride, action on
acids 144, i53> action on ketones,
195; action on salts, 159-
Phosphorus pentoxide, cymene from
camphor by means of, 56; nitrile
from amide by, 147 ; to dry ether,
74-
Phosphorus trichloride, action on
acids, 144, 148.
Phosphorus trisulphide, use in pre-
paring thiophene, 262.
Phthalic anhydride, anthranilic acid
from, 234; o-benzoylbenzoic acid
from, 104; condensation of with a
hydrocarbon, 103; preparation of a
condensation product from, I4 1 -
Phthalamidic acid, 234, 235.
Phthalic acid, from aminonaphtha-
lene, 212.
Phthalimide, 234; use in preparing
amines, 217.
Pinacone from acetophenone, 73.
Platinum black, 76.
Platinic chloride, see chloroplatinic
acid.
Polarimeter, 185.
Polymorphism, 134.
Polypeptides, 233.
Potassium bromide, ethyl bromide
from, 197; for Sandmeyer's reac-
tion, 201.
Potassium cyanide for condensation
of an aldehyde, 97-
Potassium, determination of, 24.
Potassium ferricyanide, as oxidizing
agent, 214; oxidation of toluene
sulphonamides by, 261.
Potassium hydroxide soldtion, vapor
pressure of, 14.
Potassium permanganate, oxidation
of nitro toluene with, 128; oxida-
tion of unsaturated hydrocarbon
to a glycol with test for unsat-
urated compounds, 135.
288
INDEX
Potassium phenolate, hydroxy ben-
zoic acid formed with, 164.
Potassium phthalimide, use in pre-
paring amines, 217.
Potassium pyrochromate, separation
of o- and />-toluenesulphamides by
oxidation with, 260.
Primary amines, test for, 267.
Primary secondary and tertiary
amines, separation of, 160, 267,
carboxyl, esterification of, 147; ni-
tro compounds, 210.
Pringsheim's method for determin-
ing sulphur and halogens, 21.
Propanoic acid, 119.
Propanone, 92.
Propanone oxime, 93.
i,3-Propenol, 69.
Propionic acid separation from buty-
ric acid, 107, H9'
Proteins, synthesis of, 233.
"Pseudo" form o f benzene sulphon-
amide, 161.
Pyrazolone derivative, preparation
of, 175, 178.
Pyridine derivative from acetoacetic
ester, 175, 240.
Pyridine, preparation o>f a deriva-
tive of, 240. '
Pyrimidine compounds from aceto-
acetic ester, 175.
Pyrogenic neaction for preparing hy-
drocarbons, 56-
Pulfrich inversion refractometer, 83.
Qualitative examination o f carbon
compounds, 264.
Quinazoline, preparation from an
acyl anthranilic nitrile, 239.
Quinoid form of phenolphthalein, 142.
Quinoline, Skraup's synthesis of, 238;
use in preparing hydrocarbons
from halogen compounds, 39.
Quinones, 88; hydroquinone from, 76;
from oxidation of a hydrocarbon,
103.
Raikoff receiver, 182.
Reaction, general for aldehydes, 91.
Rearrangement, Beckmann's, 102.
Rearrangements produced in carbo-
hydrates by dilute acids or en-
zymes, 185.
Reagents, 272.
Reagent, Schweitzer, 185, 189.
Receiver, Raikoff, 182.
Reducing agent for oximes, 218, 226;
for nitro compounds, 217, 220, 221.
Reduction by alcohol, 132; ammo-
nium sulphide, 217, 222; hydriodic
acid, 40, 57, 58; iron and acetic
acid, 217; nickel, 50; iodine and al-
cohol, 23, 226, 227; sodium and
moist ether, 73 > sodium amalgam,
J 34J by stannous chloride, 217,
254* tin and hydrochloric acid, 217,
221; zinc-copper couple, 4 2 J zinc
dust, 60; zinc dust, alcohol and
sodium hydroxide, 248 ; electrolytic,
136, 255; of a hydrazone to an
amine, 218; of a hydrocarbon,
Sabatier's method, 40, 50, 54; of a
diazonium compound to a hydra-
zine, 254; of an oxime to an amine,
226; of a nitro compound to an
amine, 220; to a hydrazo com-
pound, 248; to a hydroxylamine
derivative, 255 ; of a ketone by
sodium, 73 by hydriodic acid, 40,
57J halogen compounds to deter-
mine halogens, 23; of monohalo-
gen derivatives to the hydrocar-
bon, 39, 42; of unsaturated acids,
J 34, 136.
Refractometer, 83.
Replacement O f an amino group by
bromine, 201; cyanogen, 131; hy-
drogen, 41, 213; hydroxyl, 70.
Resorcinol, fluorescein from, 142.
Reversed condenser, 68.
Rochelle salt, use in Fehling's solu-
tion, 1 86.
INDEX
289
Rotation of sucrose and of invert
sugar, 1 88.
Sabatier's method for reduction of a
hydrocarbon, 5-
Saccharimeter, 185.
Saccharin, 261.
Saccharomyces ellipsoideus destroys
dextro form to effect separation,
I/O.
Salicylic acid, antiseptic properties,
166; from sodium phenolate, 164,
165; phenyl ether of, 84.
Sandmeyer reaction, 108; for a ni-
tronitrile, 239; for halogen com-
pounds, 195, 201; for preparation
of chlorobenzoic acid, 85.
Saponification o f cyanides, 107, 131*
138, 139; of an ester, 152-
Schotten-Baumann reaction, 154, 155,
1 60.
Schweitzer's reagent, 185, 189.
Secondary amine, preparation, 225,
237; test for, 267.
Semicarbazine, the hydrochloride of,
95-
Semicarbazones, 89, 95-
Separatory funnel, 127.
Separation of two fatty acids, 119,
121.
Skraup's synthesis O f quinoline, 238.
Smith, Alex, and Menzies' apparatus
for boiling-point, 269.
Soda-lime, use to prepare a hydro-
carbon, 50.
Sodium amalgam, 135; reduction ot
an unsaturated acid by, i34> 135.
Sodium anthraquinone sulphonate,
79-
Sodium benzene sulphonate, 159.
Sodium, determination of, 24.
Sodium ethylate, condensations by
action of, no, 170, 176; acetylene
by means of, 495 properties, 69.
Sodium hydroxide, reagent, 273.
19
Sodium hypobromite, preparation of
pure, 235.
Sodium hypochlorite, oxidation with,
99.
Sodium nitrite, reagent, 273.
Sodium phenolate, salicyclic acid
formed with, 164, 165-
Sodium pyrochromate, use for oxida-
tion, 77> n6.
Sodium sulphite, acid, preparation of,
97-
Sodium, wire O r small pellets, 170.
Solvents, use of, 130.
Specific gravity, determination of,
32; of alcohol, 32.
Stannous chloride, reduction by
means of, 254.
Starch potassium iodide paper, test
for nitrous acid, 255.
Starch, 184.
Steam distillation, 71.
Stearic acid, 121.
Stearin, 114.
Stereochemistry O f oximes of ben-
zil, 08.
Stereoismerism, 98, 134.
Stilbene, 244.
Stirring, apparatus for, 77.
Strontium, determination of in salt
of organic acids, 24.
Sublimation, apparatus for, 80.
Substitution, laws of in aromatic
compounds, 209, 257.
Succinate, sodium, use in preparing
thiophene, 262.
Succinic acid, 139; diethyl ester of,
152; mono-ethyl ester of, i5 x -
Succinic anhydride from the acid,
150.
Succinic ester, succinylosuccinic ester
from, no.
Succinylosuccinic ester^ no, 165, 180.
Sucrose, (cane sugar), 184; deter-
mination of specific rotation, 188;
inversion of, 185.
2QO
INDEX
Sugar, determination of the specific
rotation of invert, 188; levulinic
acid from, 192; effect of Fehling's
solution on, 185; preparation by
action of an enzyme, 187; quanti-
tative methods for determination,
185.
Sulphanilic acid, azo compound from,
252; preparation, 258.
o-Sulphamide of benzole acid, 261.
/>-Sulphobenzene-azo-a-naphthylamine
252.
Sulphonamide, phenyl, 79 J toluene,
2 59> preparation of, 259; use in
separating amines, 160.
Sulphonate, sodium benzene, 159;
sodium anthraquinone, 79.
Sulphonation, 79, 159, 259.
Sulphonechloride of toluene from
chloride of sulphuric acid, 259.
Sulphonechlorides, preparation of,
i59, 257.
Sulphone, diphenyl, 159.
Sulphonic acids, 257; by oxidation of
mercaptans, 257; from aniline, 258;
from anthraquinone, 795 from ben-
zene, 159 i from toluene, 259; iden-
tification, 271.
Sulphonium compounds, 258, ?6i.
Sulphonium hydroxide from iodides,
258.
Sulphur alcohols, 257.
Sulphur compounds, 257.
Sulphur, determination of by Car-
ius' method, 20 ; determination of
by Pringsheim's, method, 21 ; quad-
rivalence of, in the sulphonium
compounds, 262; test for, 265.
Sulphuric acid, chloride of, prepara-
tion and use in sulphonation, 2,60,
condensation by, 105, 141; "mono-
hydrate" or "absolute," 215, 216;
reagent, 272.
Tallow, saponification of, 121.
Tartaric acid, diacetyl diethyl ester
of, 155; diethyl ester of, I54J struc-
ture, 156.
Terephthalic acid from cymene, 56;
from toluic acid, 133 ; from p-
xylene, 55.
Tertiary amines, test for, 267.
Tetrabomflurorescein, 143.
Tetraldehyde, 91.
Tetramethyldiaminotriphenylmethane
242.
Thiele apparatus for determining
melting-points, 31.
Thermometer, correction of, 28.
Thiocarbonic acids, derivatives of,
268.
Thiophene, 262.
Toluene, p-bromo, ^-xylene from,
55 > chlorination, 200; nitration,
126, 122; sulphone chloride from,
259-
o-Toluene sulphonamide, 259.
/j-Toluene sulphonamide, 259.
o-Toluene sulphonechloride, 260.
/>-Toluene sulphonechloride, 260.
/>_Toluic acid, 131, 133; from cymene,
56; from /?-xylene, 55.
/>-Toluidine, />-acettoluide from, 213;
p-cresol, from, 71 ; nitration of,
214; ^-tolunitrile from, 131; p-
toluic acid from, 131, 132.
Tolunitrile, 131.
Trichloromethane, 206.
Triiodomethane, 207.
Trimethylene cyanide, synthesis of
cadaverine from, 228.
Trimethyl succinic acid from bro-
moisobutyric ester, 112.
Trimethylsulphonium iodide, 261.
Trinitrotriphenylmethane, 59.
Triphenyl carbinol, 74.
Triphenylchlormethane, trip h e n y 1 -
methyl from, 60.
Triphenylmethane, 38, 58.
Triphenylmethyl, 60.
INDEX
291
Triphenylmethyl peroxide, 60.
Tubes, sealing of, 20, 156.
Unsaturated acids, reduction of,
i34, 136.
Unsaturated alcohol, 69.
Unsaturated compounds, permanga-
nate test for, 135.
Upright condenser, 68.
Urea, from alloxan, 163 ; from phos-
gene, 158; nitrate of, 158; nitro-,
94 ; to destroy nitrous acid, 72.
Urethane obtained, to prepare amines,
219.
Uric acid, 162.
Urine, uric acid from, 162.
Vacuum distillation, 171.
Valerolactone, 193.
Vapor pressure of water and of 40
per cent, potassium hydroxide, 14.
Vinyl bromide, 49.
Volatile liquids, preservation of, 175,
197.
Volhard bath, 53.
Volhard's method of preparing a
bromine derivative of an acid, 203.
Walker's method for preparation of
ethyl or methyl iodide, 197.
Washing soluble substances, 123.
Water, vapor pressure of, 14.
Witt plate, 229.
Wood, distillation of, 34-
Wood's metal for vacuum distilla-
tions, 171.
Xanthone, 85, 105.
/>-Xylene, synthesis, 54-
Zinc alkyl compounds, hydrocarbons
from, 39, 63.
Zinc chloride, condensation by means
of, 242.
Zinc copper couple, zinc methyl by
use of, 61; ethane by use of, 42.
Zinc dust, reduction with, 60.
Zinc ethyl, 61.
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