LIBRARY 
 
 OF THE 
 
 UNIVERSITY OF CALIFORNIA. 
 
 RECEIVED BY EXCHANGE 
 
 Class 
 
The Weight of a Falling Drop and the 
 
 Laws of Tate. The Drop Weights 
 
 and Molecular Weights of Some 
 
 of the Lower Esters 
 
 DISSERTATION 
 
 SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIRE- 
 MENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY 
 IN THE FACULTY OF PURE SCIENCE IN COLUMBIA 
 UNIVERSITY IN THE CITY OF NEW YORK. 
 
 BY 
 
 FREDERICK W. SCHWARTZ 
 
 NEW YORK CITY 
 1911 
 
 EASTON, PA.: 
 
 ESCHBNBACH PRINTING Co, 
 1911. 
 
The Weight of a Falling Drop and the 
 
 Laws of Tate, The Drop Weights 
 
 and Molecular Weights of Some 
 
 of the Lower Esters 
 
 DISSERTATION 
 
 SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIRE- 
 MENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY 
 IN THE FACULTY OF PURE SCIENCE IN COLUMBIA 
 UNIVERSITY IN THE CITY OF NEW YORK. 
 
 BY 
 
 FREDERICK W. SCHWARTZ 
 
 NEW YORK CITY 
 
 1911 
 
 EASTON, PA.: 
 
 ESCHENBACH PRINTING Co. 
 1911. 
 
ACKNOWLEDGMENT. 
 
 To Professor J. Livingston R. Morgan the author wishes to 
 express his sincere thanks for advice, assistance and encourage- 
 ment afforded him throughout the work. F. W. S. 
 
 226927 
 
CONTENTS. 
 
 Introduction and object of the investigation 5 
 
 Apparatus and method 6 
 
 Results. ...!... 8 
 
 Summary 23 
 
The Weight of a Falling Drop and the Laws 
 
 of Tate. 1 The Drop Weights and 
 
 Molecular Weights of Some 
 
 of the Lower Esters* 
 
 OBJECT OF THE INVESTIGATION. 
 
 As has been shown in former researches, 2 the weight of a 
 drop of liquid falling from a properly constructed tip is pro- 
 portional, for any one diameter of tip, to the surface tension 
 of the liquid; and further, that when falling drop weights are 
 substituted for surface tensions in the formula of Eotvos, 3 
 as modified and presented by Ramsay and Shields, 4 the molec- 
 ular weights and critical temperatures of liquids can be calcula- 
 ted with an accuracy equal to that attained by the use of the 
 surface tensions from the capillary rise method, notwith- 
 standing the statements of Guye and Perrot 5 to the contrary. 
 The object of this investigation has been the testing of the 
 new definition of normal molecular weight in the liquid state 
 as given by Morgan and the comparison of the surface tensions 
 and critical temperatures of some of the lower esters, deter- 
 mined by capillary rise and drop weight methods. The esters 
 chosen for this investigation were methyl formate, ethyl 
 formate, propyl formate, amyl formate, methyl acetate, ethyl 
 acetate, propyl acetate, methyl propionate, ethyl propionate, 
 methyl butyrate and methyl isobutyrate. 
 
 With the aid of a simple form of apparatus devised by 
 Professor Morgan, the determination of the drop weights of 
 
 1 Tate, Phil. Mag., 4th Ser., 27, 176 (1864). 
 
 2 Morgan and Stevenson, Jour. Am. Chem. Soc., 30, No. 3; Morgan 
 and Higgins, Jour. Am. Chem. Soc., 30, No. 7. 
 
 3 Eotvos, Wied. Ann., 27. 
 
 4 Ramsay and Shields, Zeit. phys. Chem., 12, 1893. 
 
 5 Guye and Perrot, Arch. Sci. Phys. et Nat., 4 s., n (1901); 4 s., 15 
 (1903). 
 
liquids has been rendered more simple than by the methods 
 used by Morgan and Higgins and Morgan and Stevenson. 
 
 APPARATUS AND METHOD. 
 
 The apparatus and methods used were the same as de- 
 scribed by Morgan. 1 The chemicals with the exception of amyl 
 formate were manufactured especially for this investigation 
 by the Hoffman and Kropff Chemical Company, and were 
 exceptionally pure and gave entire satisfaction. The amyl 
 formate was obtained from Messrs. Kimer and Amend and was 
 purified before use. 
 
 The following symbols and abbreviations have been use 
 throughout this work : 
 
 / = centigrade temperature. 
 T c = critical temperature. 
 
 A = weight in grams of vessel plus 25 drops of liquid. 
 B = weight in grams of vessel plus 5 drops of liquid. 
 C = average weight in grams of vessel plus 25 drops of 
 
 liquid. 
 D = average weight in grams of vessel plus 5 drops of 
 
 liquid. 
 
 D. W. = weight in milligrams of one drop of liquid. 
 K = drop weight constant. 
 K' = surface tension constant. 
 f = surface tension hi dynes per square centimeter. 
 d = density. 
 
 M = molecular weight in the liquid state. 
 For the calculation of K the following modified equation of 
 Ramsay and Shields has been used. 
 
 - where W = the drop weight in milligrams. 
 
 T c (t + 6) 
 
 Surface tension being proportional to drop weights, as 
 shown by Morgan the following equation was used to calculate 
 surface tension : 
 
 f = - ^ , from the proportion, ? : D. W. :: K' : K. 
 JK. 
 
 1 Morgan, Jour. Am. Chem. Soc., 33, No. 3. ; 
 
STANDARDIZATION OF TIP. 
 
 
 
 Benzene. 
 
 , M = 
 
 78. T c = 
 
 288.4. 
 
 
 t' 
 
 
 A. 
 
 B. 
 
 c. 
 
 D. 
 
 D.W. 
 
 10. 
 
 7 
 
 6515 
 
 7.0063 
 
 
 
 
 
 7 
 
 .6516 
 
 7.0062 
 
 
 
 
 
 7 
 
 6515 
 
 7 . 0064 
 
 
 
 
 
 7 
 
 .6514 
 
 7.0063 
 
 7 6515 
 
 7.0063 
 
 32.26 
 
 40.7 
 
 ii 
 
 0195 
 
 10.4610 
 
 
 
 
 
 ii 
 
 .0194 
 
 10.4612 
 
 
 
 
 
 ii 
 
 .0194 
 
 10.4611 
 
 
 
 
 
 ii 
 
 0193 
 
 10.4611 
 
 ii .0194 
 
 I0.46II 
 
 27-9I5 
 
 t. 
 
 
 d. 
 
 D. W. 
 
 w( M ) 2/s - 
 
 K. 
 
 Mean K. 
 
 10. 
 
 o 
 
 8895549 
 
 32.26 
 
 636 . 72 
 
 2-3374 
 
 
 40.7 
 
 
 
 .8568299 
 
 27.915 
 
 564 . 90 
 
 2-3372 
 
 2 -3373 
 
 
 
 Pyridine. 
 
 M = 79- T, = 
 
 346.6. 
 
 
 /. 
 
 
 A. 
 
 B. 
 
 c. 
 
 D. 
 
 D.W. 
 
 0. I 
 
 8 
 
 5643 
 
 7.6986 
 
 
 
 
 
 8 
 
 5642 
 
 7.6984 
 
 
 
 
 
 8 
 
 5643 
 
 7-6984 
 
 
 
 
 
 8 
 
 5644 
 
 7.6985 
 
 8.5643 
 
 7-69847 
 
 43 292 
 
 34.25 
 
 ii 
 
 7086 
 
 10.9472 
 
 
 
 
 
 ii 
 
 7084 
 
 10-9472 
 
 
 
 
 
 ii 
 
 7085 
 
 10.9474 
 
 
 
 
 
 ii . 
 
 7087 
 
 !0-9475 
 
 
 
 
 
 ii . 
 
 7088 
 
 10.9472 
 
 I I . 7086 
 
 10.9473 
 
 38.005 
 
 t. 
 
 
 d. 
 
 D.W. 
 
 W ( M ) 2/3 - 
 
 K. 
 
 Mean K. 
 
 0. I 
 
 i . 
 
 0014 43.292 
 
 796.31 
 
 2-3359 
 
 
 34-25 
 
 0. 
 
 9672 38.005 
 
 716.58 
 
 2 336o 
 
 2 -33595 
 
 The diameter of the tip was 5.53 millimeters. 
 
 The constant used throughout the work was the benzene 
 constant 2.3373. In the standardization of the tip, only the 
 results given by benzene were used, in order to make com- 
 parisons with the results of other observers who also used 
 benzene as a standardizing liquid. The K used was found 
 by use of the modified Ramsay and Shields formula using the 
 various benzene values. 
 
 The surface tensions were all calculated from the formula 
 as given previously, K' being the constant given by the in- 
 vestigators who used the capillary rise method. 
 
8 
 
 DISCUSSION OF RESULTS. 
 NEW LIQUIDS. 
 
 In Tables 24-48 are given the wf j and the T c values 
 
 /M\ 8/ 3 
 calculated from K in the relationship W ( -= J = K (T c t 6) 
 
 using the molecular weights of Young and Thomas, 
 together with the values from capillary rise. It will be re- 
 membered here that normal molecular weight (Morgan) is 
 shown by the attainment of the same calculated value of T c from 
 
 /M\ s > 
 the equation W( -j J = K(T C t 6) at all temperatures of 
 
 observation. 
 
 Agreement of the values of T c from drop weight and surface 
 tension would show then further, that D. W. : 7- :: K : K', 
 for the molecular weight, is the same and the density is the 
 same function of temperature in all cases. To prove the 
 relationship D. W. : 7- :: K : K/ directly, the values of 7- are 
 given both from drop weight and from curves in Tables 12-23. 
 
 In Tables i-n, the experimental results are given for the 
 esters. The agreement between the results of any one liquid 
 at any one temperature, show that great accuracy may be 
 attained in every case. An examination of columns, A, B, 
 C, D, in these tables shows in some series great differences at 
 various temperatures due to various weighing vessels used. 
 
 In Tables 12-23 are comparisons of the surface tensions by 
 drop weight and capillary rise methods. It will be seen that 
 remarkable agreements are obtained in nearly all cases, even 
 in those in which the results were extrapolated far beyond the 
 experimental points. It is to be doubted in some cases where 
 the agreement is not very close, that the K' for benzene from 
 capillary rise was determined with as great accuracy as it was 
 for the esters. This is to be especially noted in Table 14. 
 
 In Tables 16-23 the disagreement of the results of Ramsay 
 and Aston with tubes of different radii is often greater than 
 when compared with those results taken from the curve. 
 
9 
 TABLE i. Methyl formate. 
 
 /. A. B. C. D. D. W. 
 
 o.i 8.2323 7.6345 
 
 8.2323 7-6345 
 8.2325 7-6345 
 
 8.2324 7-6346 8.23237 7-63452 29.893 
 6.7 8.3898 7.8125 
 
 8.3898 7.8126 
 
 8.3897 7-8125 
 8.3897 7.8126 8.38975 7-81255 28.86 
 
 10. o 7-5554 6.9906 
 
 7-5553 6.9906 
 
 7-5554 6.9904 
 
 7-5555 6.9906 7-5554 6.99055 28.243 
 
 16.4 8.3485 7-8013 
 
 8.3486 7-8013 
 
 8.3485 7-8013 
 
 8.3484 7-8013 8.3485 7-8013 27.36 
 
 27.82 8.3071 7-7948 
 8 - 3072 7 7949 
 8.3071 7-7949 
 
 8.3073 7-7950 8.30717 7 7949 25.614 
 TABLE 2. Ethyl formate. 
 
 o.i 8.1827 7.6228 
 
 8.1827 7.6230 
 
 8.1828 7.6230 
 8.1828 7.6231 
 
 7.6231 8.18275 7.6229 27.993 
 
 6.0 8.3243 7-7809 
 
 8.3243 7.7810 
 8 . 3242 7 . 7808 
 
 8.3244 7-7809 8.3243 7-7809 27.17 
 10. o 8.3355 7.8028 
 
 8.3358 -7-8030 
 
 8-3357 7-8029 
 
 8-3357 7-8030 8.33567 7.80292 26.638 
 
 17.0 8.2888 7-7751 
 
 8.2886 7-7752 
 
 8.2889 7-7753 
 
 8.2889 7-7752 8.2888 7-7752 25.68 
 
 33 95 10.9059 10.4381 
 
 10.9058 10.4382 
 
 10.9059 10.4380 
 
 10.9060 10.4383 10.9059 10.43815 23.388 
 
10 
 
 TABLE 3. Propyl formate. 
 
 A. 
 
 B. 
 
 C. D. D. W. 
 
 7.5616 
 
 6 - 9895 
 
 
 7-56I5 
 
 6.9895 
 
 
 7-56I5 
 
 6 . 9894 
 
 
 7-56I5 
 
 6.9894 
 
 7 . 561 52 6 . 98945! 28 . 604 
 
 8.3638 
 
 7 8050 
 
 
 8.3639 
 
 7 8050 
 
 
 8.3638 
 
 7 8050 
 
 
 8-3638 
 
 7 . 8050 
 
 8.36382 7-8050 27.941 
 
 8 . 3492 
 
 7 . 8026 
 
 
 8-3494 
 
 7.8027 
 
 
 8 3494 
 
 7.8027 
 
 
 8 3494 
 
 7.8025 
 
 8.34935S:7 -80262 27.337 
 
 8-3283 
 
 7 7992 
 
 
 8.3284 
 
 7.7992 
 
 
 8.3284 
 
 7 7992 
 
 
 8.3283 
 
 7 7992 
 
 8-32835 7-7992 26.458 
 
 7-4595 
 
 6-9733 
 
 
 7-4593 
 
 6-9735 
 
 
 7-4594 
 
 6.9736 
 
 
 7-4595 
 
 6-9735 
 
 7.45942 6.97347 24.298 
 
 7 3903 
 
 6.9620 
 
 
 7 3903 
 
 6.9619 
 
 
 7 3902 
 
 6.9619 
 
 
 7 3905 
 
 6.9619 
 
 
 7 3902 
 
 
 7.3903 6.96192 21.419 
 
 5-4 
 
 10. o 
 
 17.0 
 
 34-75 
 
 60.3 
 
 TABLE 4. Amyl formate. 
 
 10. o 8.3484 7-7993 
 
 8 . 3486 7 . 7992 
 
 8.3485 7-7992 
 
 8.3485 7-7992 8.3485 7-79922 27.464 
 
 35.0 8.2813 7-7875 
 
 8.2813 7-7875 
 
 8.2814 7-7875 
 
 8.2812 7-7875 8.2813 7-7875 24.69 
 
 60. i 8.2176 7 7796 
 
 8.2176 7-7796 
 
 8.2177 7-7797 
 8.2177 7-7795 
 
 8.2177 8.21767 7.7796 21.904 
 
II 
 TABLE 5. Methyl acetate. 
 
 A. B. ~C. D. D. W. 
 
 o.i 8.2152 7.6292 
 
 8.2151 7.6291 
 8.2I5O 7.6291 
 
 8.2152 7.6290 8.2I5I2 7.6291 29.301 
 
 10. O 
 
 34-20 
 
 0. I 
 
 34.60 
 
 60.5 
 
 0. I 
 
 34.60 
 
 60. I 
 
 6 . 8070 
 
 6.2510 
 
 
 
 6 . 8069 
 
 6.2509 
 
 
 
 6 . 8068 
 
 6.2508 
 
 
 
 6 . 8068 
 
 6.2507 
 
 6.80687 6.25085 
 
 27.801 
 
 8.2822 
 
 7 7990 
 
 
 
 8.2823 
 
 7.7991 
 
 
 
 8.2822 
 
 7.7991 
 
 
 
 8.2824 
 
 7.7991 
 
 8.28227 7.79907 
 
 24. 16 
 
 TABLE 6. Ethyl acetate. 
 
 7-54 21 
 
 6.9834 
 
 
 
 7-5420 
 
 6.9834 
 
 
 
 7-5421 
 
 6.9832 
 
 
 
 7-5422 
 
 6.9832 
 
 7.5421 6.9833 
 
 27.94 
 
 7.4442 
 
 6.9767 
 
 
 
 7-4443 
 
 6.9768 
 
 
 
 7-4443 
 
 6.9767 
 
 
 
 7.4442 
 
 6.9769 
 
 
 
 7.4442 
 
 6 . 9766 
 
 7.44424 6.97674 
 
 23-375 
 
 7-3658 
 
 6 . 9646 
 
 
 
 7.3659 
 
 6 . 9647 
 
 
 
 7-3659 
 
 6 . 9646 
 
 
 
 7 3660 
 
 6 . 9646 
 
 7-3659 6.96462 
 
 20.064 
 
 TABLE 7. 
 
 -Propyl acetate. 
 
 
 8. 1884 
 
 7.6199 
 
 
 
 8.1885 
 
 7.6198 
 
 
 
 8.1886 
 
 7.6199 
 
 
 
 8.1887 
 
 7.6200 
 
 8.18855 7-6199 
 
 28-433 
 
 7.4602 
 
 6.9773 
 
 
 
 7-4603 
 
 6.9773 
 
 
 
 7.4602 
 
 6.9772 
 
 
 
 7 . 4602 
 
 6.9773 
 
 7.46022 6.97727 
 
 24. 148 
 
 ii . 1213 
 
 10.6972 
 
 
 
 ii . 1216 
 
 10.6973 
 
 
 
 11.1215 
 
 10.6974 
 
 
 
 11.1215 
 
 10.6974 
 
 11.12147 10.69732 
 
 2 I . 208 
 
12 
 
 TABLE 8. Methyl propionate. 
 
 A. B. C. D. D. W. 
 
 6.8100 6.2513 
 
 6. 8102 6.2513 
 
 6.8100 6.2512 
 
 6.8101 6.2510 6.81007 6.2512 27.944 
 34.65 0.9364 10.4426 
 
 10.9362 10.4425 
 
 10.9363 10.4425 
 
 10.9363 10.4427 10.9363 10.44257 24.687 
 
 59.75 10.8000 10.3701 
 
 10.8002 10.3703 
 
 10.8002 10.3702 
 
 10.8001 10.3699 10.8001 10.37012 21.499 
 10.8000 
 
 TABLE 9. Ethyl propionate. 
 
 6.7887 6.2480 
 
 6 . 7888 6 . 2480 
 6.7888 6.2478 
 
 6.7887 6.2478 6.78875 6.2479 27.043 
 
 33.89 9-8185 9-3356 
 
 . 9.8187 9.3356 
 
 9.8186 9-3355 
 
 9.8186 9-3356 9.8186 9-33557 24.152 
 
 59.15 10.7920 10.3682 
 
 10.7921 10.3682 
 
 10.7920 10.3681 
 
 10.7919 10.3680 10.7920 10.36812 21.194 
 
 TABLE 10. Methyl isobutyrate. 
 
 10.0 9.8776 9-3452 
 9-8775 9-3450 
 9-8773 9-3451 
 
 9.8776 9-3452 9-8775 9-345 12 26.619 
 
 33.87 9-8085 9-3336 
 
 9.8084 9-3337 
 
 9.8083 9-3335 
 
 9.8083 9-3338 
 
 9.8087 9.3338 9-80845 9-33366 23.740 
 
 10. i 9.7385 9-3260 
 9-7386 9-3261 
 
 9-3259 
 9-3259 
 9-3259 9 73862 9 32594 20.634 
 
13 
 
 TABLE n. Methyl butyrate. 
 t. A. B. c. D. D.W. 
 
 10. o 8.3627 7-8043 
 
 8.3626 7.8042 
 
 8.3627 7.8042 
 
 8.3625 7.8042 8.36262 7.80422 27.92 
 
 34.8 8.2869 7-7885 
 
 8.2867 7.7885 
 
 8.2868 7.7885 
 
 8.2868 7.7885 8.2868 7-7885 24.915 
 
 59.85 8.2217 7-7824 
 
 8.2218 7.7824 
 
 8.2217 7-7824 
 
 8.2216 7.7824 8.22168 7.7824 21.964 
 8.2216 
 
 SURFACE TENSION. 
 TABLE 12. Methyl formate. 
 
 t. >R. & S. 1 . r- From curves, (w ~ ) 
 
 20. o 24.64 24.11 
 
 30.0 23.09 22.72* 
 
 40.0 21.56 21.34* 
 
 50.0 20.05 T 9 95* 
 
 60.0 18.58 18.57* 
 
 70.0 17-15 17.19* 
 
 TABLE 13. Amyl formate. 
 
 t. r H. & G. 2 r- Prom curve S. (w *-""' 
 
 43.8 21.64 21.51 
 
 77.8 18.40 18.12* 
 
 109-2 I5-52 I5-05* 
 
 1 Ramsay and Shields, Zeit. phys. Chem., 1893. 
 
 2 Homfray and Guye, Jour, de Chem. Phys., 1903, i. 
 
14 
 TABLE 14. Ethyl acetate. 
 
 2.106 
 
 /. 
 
 r- r. From curve S. ( w ~ 1 
 v 2.3373^ 
 
 9-5 
 
 24.71 G. & B. 1 24.05 
 
 12.9 
 
 24.14 R. &G. 2 23.74 
 
 20. o 
 
 23.60 R. &S. 22.82 
 
 3i-3 
 
 21.87 R. &G. 21.43 
 
 46.9 
 
 20.11 R. &G. 19.63 
 
 55-o 
 
 19.06 R. &G. 18.70 
 
 55-6 
 
 18.82 G. & B. 18.63 
 
 65-9 
 
 17.76 R. &G. 1745* 
 
 73-5 
 
 17.07 R. &G. 16.57* 
 
 77.0 
 
 16.63 G. & B. 16.17* 
 
 80.0 
 
 16.32 R. &S. 15-83* 
 
 90.0 
 
 15.14 R. &S. 14.67* 
 
 IOO.O 
 
 13.98 R. &S. 13-53* 
 
 
 TABLE 15. Methyl isobutyrate. 
 
 j 
 
 , 2.no8 x 
 
 *. 
 
 f R. & G. y* Fiom curve o. f zf j 
 
 10.5 
 
 24.06 24.03 
 
 30-5 
 
 21.82 21. 81 
 
 41 .0 
 
 20.63 20.68 
 
 55-o 
 
 19. 18 19. 18 
 
 75-o 
 
 17.02 17. 04* 
 
 86.6 
 
 15.78 15.80* 
 
 
 TABLE 16. Ethyl formate. 
 
 r = 
 
 0.01843 cm. r = 0.01046 cm. 
 
 /. 
 
 r R. & A. 8 r R & A. r from curve S. 
 
 IO.O 
 
 24.08 24.22 24.18 
 
 46-5 
 
 19.50 I9.7I 19.68* 
 
 78-5 
 
 15.68 15.68 15-73* 
 
 TABLE 17. Methyl acetate. 
 r 0.01843 cm. r = 0.01046 cm. 
 
 /. rR-&A. r R - & A. j- from curve S. 
 
 10.0 25.22 25.06 25.23 
 
 46.2 20.32 20.49 20.29* 
 
 78.3 16.28 16.35 15-89* 
 
 1 Guye and Baud, Arch, des Sci. Phys. et Nat., 4 s., Vol. n. 
 
 2 Renard and Guye, Jour, de Chem. Phys., 1907, 5. 
 
 3 Ramsay and Aston, Zeit. phys. Chem., 15 (1894), Part i. 
 
 *A11 values thus marked were extrapolated beyond points on curve. 
 T K = 2.106 being a mean of R. & S. and R. & G. 
 
TABLE 18. Propyl formate. 
 
 r = 0.01843 cm. 
 
 r = 0.01046 cm. 
 
 t. r R- & A. 
 
 r R. & A. r from curve S. 
 
 10. o 25.02 
 
 25.06 24.81 
 
 46 . 2 20 . 67 
 
 20.71 20.83 
 
 78.2 17.52 
 
 17.44 17-61* 
 
 TABLE 19. Methyl propionate. 
 
 r = 0.01708 cm. 
 
 r = 0.01046 cm. 
 
 /. r R. & A. 
 
 r R & A. r from curve S. 
 
 10. o 25.23 
 
 25-5I 25.36 
 
 46.2 20.85 
 
 20.98 2 I. 08 
 
 78.2 17.11 
 
 17.26 17.30* 
 
 TABLE 20.- 
 
 Propyl acetate. 
 
 r = 0.01708 cm. 
 
 r = 0.01046 cm. 
 
 t. rR.&A. 
 
 r R. & A. r from curve S. 
 
 10. o 24.00 
 
 24 .88 24 . 69 
 
 46 . 2 20 . 86 
 
 20.84 20.71 
 
 78-2 17-35 
 
 17.41 17.36* 
 
 TABLE 21. Ethyl propionate. 
 
 r = 0.01708 cm. 
 
 r = 0.01046 cm. 
 
 /. r R. &A. 
 
 r R. & A. r from curve S. 
 
 10. o 24.57 
 
 24.57 24.54 
 
 46.2 20.58 
 
 2O.62 2O.6O 
 
 78.2 17.24 
 
 17.22 17.20* 
 
 TABLE 22. Methyl isobutyrate. 
 
 r = 0.01708 cm. 
 
 r 0.01046 cm. 
 
 t. r R. & A. 
 
 r R. & A. r from curve S. 
 
 10. 24.11 
 
 24.08 24.16 
 
 46.2 20.29 
 
 20.04 2O.22 
 
 78.2 16.70 
 
 16.64 16.78* 
 
 TABLE 23.- 
 
 -Methyl butyrate. 
 
 r = 0.01843 cm. | 
 
 r = 0.01046 cm. 
 
 t. rR. &A. 
 
 r R. & A. r from curve S. 
 
 10. o 25.63 
 
 25.50 25.34 
 
 46 . 2 2 I . 50 
 
 21.39 21.40 
 
 78.2 18.15 
 
 18.05 I7-98* 
 
 *A11 values thus marked were extrapolated beyond points on curve. 
 
i6 
 
 In Tables 24-29 are given the critical temperatures of 
 various investigators using the K as indicated in the tables. 
 It is rather difficult to compare directly these results with those 
 obtained by the drop weight method. 
 
 In Tables 25-27 with ethyl acetate it may be seen that the 
 results agree well although differences in temperature are 
 considerable. 
 
 Comparing Table 24 with Table 38 (methyl formate) it will 
 be noticed that the critical temperatures do not agree as well 
 as might be expected, but this may be well explained by 
 polymerization at the higher temperatures. 
 
 In Tables 25-27 and 43 (ethyl acetate) the results in 43 
 show a closer agreement with those of Young than with those 
 of other workers. 
 
 In Tables 29 and 41 (amyl formate) the results in 41 also 
 show a closer agreement with those determined experimentally. 
 
 In Tables 30-37 the differences between the critical tem- 
 peratures determined with different tubes are quite noticeable, 
 while with Tables 39, 40, 42-48 will show very good agree- 
 ment. 
 
 From these agreements of critical temperatures calculated 
 in Tables 38-48 it may be stated that a liquid which will give 
 the same critical temperature at various expeiimental tem- 
 peratures has normal molecular weight. Those liquids which 
 do not, are either associated or as in this case decomposed 
 at the higher temperatures. After working for some time 
 with the formates, it became quite evident that an explanation 
 was necessary, in view of the non- concordant results that were 
 obtained, there being a general trend in the calculated critical 
 temperatures with variation of temperature. It was decided 
 to investigate the effect of heat on several of the formates, 
 those chosen being propyl and amyl formate. 
 
 Propyl formate was heated for two and one-half hours at 
 60 under atmospheric pressure and allowed to cool slowly 
 to room temperature. 
 
 Unheated sample gave drop weight at 10.0 = 27.337. 
 
 Heated sample gave drop weight at 10.0 = 27.434 deter- 
 mined immediately. 
 
17 
 
 Heated sample gave drop weight at 10.0 = 27.430 after 
 1 6 hours. 
 
 Heated sample gave drop weight at 10.0 = 27.366 after 
 10 days. 
 
 Another sample was heated similarly and cooled suddenly 
 to 0.0 and the drop weight immediately determined which 
 gave 27.337. 
 
 These results show that some change had taken place which 
 was apparently reversible and which is influenced largely by 
 time and temperature. 
 
 Amyl formate was heated to 230 in a sealed tube with a 
 small amount of mercury for three and three-fourths hours. 
 On opening the thoroughly cooled tube considerable pressure 
 was noticed. 
 
 Unheated sample gave drop weight at 10.0 = 27.464. 
 
 Heated sample gave drop weight at 10.0 = 27.309. 
 
 In both cases a decided differences of odor was noticed be- 
 tween the heated and unheated samples. As an explanation 
 for this variation it may be assumed to be due to polymerization 
 for lack of more confirmatory evidence. Polymerization at 
 higher temperatures has been noticed by Young and Thomas 1 
 in the case of the formates and by Homfray and Guye 2 with 
 liquids such as ethyl lactate. However Smiles 3 states "it is 
 doubtful that the effect of temperature is related to the chemical 
 constitution of the liquid." The formates, then may be 
 classed as the exceptions to the statement of Gossart 4 "that 
 the temperature coefficient is the same for substances of the 
 same class," although his measurements deal only with the 
 alcohols, acids, esters and some chlorine derivatives. 
 
 CRITICAL TEMPERATURE. 
 
 The following were calculated from the results of Ramsay 
 and Shields 5 using K = 2.1012. 
 
 1 Young and Thomas, Trans. Chem. Soc., 1893. 
 
 2 Homfray and Guye, Jour, de Client. Phys., 1903, i. 
 
 3 Smiles, Text-book, relations between chem. constitution and some 
 physical properties, 1910. 
 
 4 Gossart, Ann. chim. phys., [6] 19173 (1890). 
 
 5 Ramsay and Shields, Zeit. phys. Chem., 1893. 
 
i8 
 TABLE 24. Methyl formate. 
 
 r(P % T, 
 
 20.0 383.9 208.70 
 
 30.0 363-7 209.09 
 
 40.0 343.2 209.33 
 
 50.0 322.6 209.53 
 
 60 . o 302 . 5 209 . 96 
 
 70.0 282.7 210.54 
 
 190.0 37.7 213.94 
 
 200.0 19.2 215.13 
 
 211. 4-0 217.89 
 
 TABLE 25. Ethyl acetate. 
 
 20.0 500.7 264.29 
 
 80.0 367 .2 260.75 
 
 90.0 344.4 259.90 
 
 100. o 321.7 259.10 
 
 no.o 299.0 258.29 
 
 120.0 277.1 257.87 
 
 245.0 7-2 254.42 
 
 The following were calculated from the results of Guye and 
 Baud 1 using K = 2.1012. 
 
 TABLE 26. Ethyl acetate. 
 
 K*) 2 "- 
 
 9-5 5I9-6 262.78 
 55-6 413-0 258.15 
 77-o 373-o 260.51 
 
 The following were calculated from the results of Renard 
 and Guye 2 using K = 2.1108. 
 
 TABLE 27. Ethyl acetate. 
 
 K")*- 
 
 12.0 509.0 260.04 
 
 31.3 470.0 259.96 
 
 46-9 437-0 259.93 
 
 55-o 418.0 259.02 
 
 65-9 394-0 258.55 
 
 73-5 381-0 259.99 
 
 1 Guye and Baud, Arch. Sci. Phys. et Nat., 4 s., Vol. n. 
 
 2 Renard and Guye, Jour, Chimie Physique, 5, 1907. 
 
TABLE 28. Methyl isobutyrate. 
 
 io-5 5 6 3-o 283.22 
 
 30.5 519.0 282.37 
 41.0 496.0 281.98 
 55.0 467.0 282.24 
 75.0 422.0 280.95 
 
 86.6 396.0 280.25 
 
 The following were calculated from the results of Homfray 
 and Guye 1 using K = 2.1012. 
 
 TABLE 29. Amyl formate. 
 /. r (^) 2/3 ' ^ c - 
 
 43-8 569-5 320.83 
 
 77-8 497-8 320.71 
 
 109.2 432.2 320.89 
 
 The following were calculated from the results of Ramsay 
 and Aston 2 using K = 2.1212. 
 
 TABLE 30. Ethyl formate. 
 r = 0.01843 cm. r = 0.01046 cm. 
 
 10. o 443-5 225.07 446.0 226.25 
 
 46-5 371-5 227.63 375.5 227.51 
 
 78.5 309-2 230.17 309.1 230.22 
 
 TABLE 31. Methyl acetate. 
 
 r = 0.01843 cm. r = 0.01046 cm. 
 
 10. o 462.8 234.17 459-9 232.90 
 
 46.2 383-9 233.17 387.2 234.53 
 
 78.3 3i8.2 234.30 319.5 234.91 
 
 TABLE 32. Propyl formate. 
 r = 0.01843 cm. r = 0.01046 cm. 
 
 10. o 523.6 262.83 524-4 263.21 
 
 46.2 446-3 262.59 447.1 262.97 
 
 78.3 387-0 266.64 385.2 265.79 
 
 1 Homfray and Guye, Jour, de Chem. Phys., 1903, i. 
 
 2 Ramsay and Aston, Jour. Chem. Soc. Trans., 65, 1894. 
 
20 
 
 TABLE 33. Methyl propionate. 
 r = 0.01708 cm. r = 0.01046 cm. 
 
 IO.O 
 
 46.2 
 
 78.2 
 
 524.3 263.16 
 447.3 263.07 
 378.8 262.77 
 
 530.2 265.95 
 450.2 264.39 
 381.9 264.28 
 
 
 TABLE 34. Propyl 
 
 acetate. 
 
 
 r = 0.01708 cm. 
 
 r = 0.01046 cm. 
 
 I. 
 
 r(^) 2 /3- TV 
 
 r (^?) ' 3 ^ c ' 
 
 IO.O 
 
 46.2 
 
 78.2 
 
 580.2 289.52 
 503.0 289.32 
 431.0 287.38 
 
 582.0 290.34 
 502.2 288.94 
 432.3 287.99 
 
 TABLE 35. Ethyl propionate. 
 
 
 r = 0.01708 cm. 
 
 r = 0.01046 cm. 
 
 IO.O 
 
 46.2 
 
 78.2 
 
 574.0 286.59 
 496.1 286.07 
 428.1 286.01 
 
 576.2 287.63 
 496.9 286.44 
 
 427.8 285.87 
 
 TABLE 36. Methyl isobutyrate. 
 
 
 r = 0.01708 cm. 
 
 r = 0.01046 cm. 
 
 IO.O 
 
 46.2 
 
 78.2 
 
 563.6 281.69 
 487.3 281.92 
 415.0 279.84 
 
 563.0 281.41 
 486.1 281.30 
 415.1 279.88 
 
 TABLE 37. Methyl butyrate. 
 
 
 r = 0.01843 cm. 
 
 r = 0.01046 cm. 
 
 IO.O 
 
 46.2 
 
 78.2 
 
 595.0 296.50 
 514.5 294.74 
 446.9 294.88 
 
 591.7 294.94 
 511.8 293.47 
 444-4 293.70 
 
 
 TABLE 38. Methyl 
 
 formate. 
 
 
 59.86. T c = 214 Young 
 
 /2. IOI2X 
 
 1 v n f , I 1 
 
 
 
 . w \ ' 
 V2-3373/ 
 
 t. 
 
 D. W. d. W(^ 
 
 )% TC. r . 
 
 0. I 
 
 6-7 
 
 IO.O 
 
 16.4 
 
 27.82 
 
 29.893 1.00300 456. 
 
 28.86 0.99354 443- 
 28.243 0.98892 435. 
 27.36 0.97943 424. 
 25.614 0.96320 401. 
 
 50 201.41 26.873 
 
 53 202.46 25.945 
 39 202.27 25.390 
 51 204.02 24.596 
 86 205.75 23.027 
 
 S. Young, Sci. Proc. Roy. Dub. Soc., 12, p. 374. 
 
21 
 
 TABLE 39. Ethyl formate. 
 
 M T-2 
 
 \-\ T 
 
 
 /^ > f <*i 
 
 o Vi~kii 
 
 /2 
 
 .1212 
 
 \ 
 
 - l J.c 
 
 'o* < 
 
 : ^OO-J A *-"" X 5- "}"' M' 
 
 3373^ 
 
 t. D. W. 
 
 d. 
 
 ,M^2/ 3 T< . ^ 
 
 0, 
 
 i 
 
 27 
 
 993 
 
 0.94697 
 
 510 
 
 .86 
 
 224 
 
 .66 
 
 25 
 
 401 
 
 6 
 
 o 
 
 27 
 
 17 
 
 
 
 93958 
 
 499 
 
 59 
 
 225 
 
 25 
 
 24 
 
 658 
 
 10. 
 
 
 
 26.638 
 
 
 
 93458 
 
 490 
 
 42 
 
 225 
 
 .82 
 
 24 
 
 175 
 
 17 
 
 
 
 25.68 
 
 0.926l8 
 
 475 
 
 .64 
 
 226 
 
 50 
 
 23. 
 
 306 
 
 33- 
 
 95 
 
 23 
 
 .388 
 
 O 
 
 .90418 
 
 440 
 
 .18 
 
 228 
 
 .27 
 
 21 
 
 226 
 
 TABLE 
 
 40. Propyl 
 
 formate. 
 
 M 
 
 
 87.8 
 
 . T c 
 
 == 
 
 264.85 
 
 Young. 
 
 r - * 
 
 (2 
 
 . 1212 
 
 \ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 2 
 
 3373/ 
 
 o. 
 
 I 
 
 28 
 
 .604 
 
 o 
 
 .92850 
 
 593 
 
 .69 
 
 260 
 
 . 10 
 
 2f; 
 
 960 
 
 5- 
 
 4 
 
 27 
 
 .941 
 
 o 
 
 92251 
 
 582 
 
 44 
 
 260 
 
 59 
 
 25- 
 
 358 
 
 10. 
 
 
 
 27 
 
 337 
 
 0.91726 
 
 572 
 
 .01 
 
 260 
 
 .72 
 
 24. 
 
 809 
 
 17 
 
 o 
 
 26 
 
 458 
 
 
 
 90909 
 
 556 
 
 93 
 
 261 
 
 .27 
 
 24 
 
 OI2 
 
 34- 
 
 75 
 
 24 
 
 .298 
 
 0.88873 519 
 
 25 
 
 262 
 
 .90 
 
 22, 
 
 051 
 
 60. 
 
 3 
 
 21 
 
 .419 
 
 o 
 
 85837 
 
 468 
 
 .46 
 
 266 
 
 .72 
 
 19 
 
 439 
 
 TABLE 41. 
 
 Amyl 
 
 formate. 
 
 M 
 
 
 116. 
 
 i IV 
 
 
 104-6 
 
 Palewski. 1 
 
 Hf* * 
 
 . IOI2 
 
 \ 
 
 
 
 V 
 
 J \ ~ 
 
 
 
 
 
 
 
 
 
 
 
 \2 
 
 3373 
 
 / 
 
 10. 
 
 
 
 27 
 
 .464 
 
 
 
 ,8882 
 
 706 
 
 .26 
 
 318 
 
 .60 
 
 24- 
 
 686 
 
 35- 
 
 
 
 24 
 
 .69 
 
 0. 
 
 8682 
 
 645 
 
 73 
 
 317 
 
 30 
 
 22 . 
 
 199 
 
 60. 
 
 I 
 
 21 
 
 .904 
 
 o. 
 
 8420 
 
 584 
 
 .62 
 
 316 
 
 ,20 
 
 19- 
 
 691 
 
 TABLE 
 
 42. Methyl 
 
 acetate. 
 
 M 
 
 = 73.83. T c = 
 
 233.7 
 
 Young. 
 
 
 (2 . 
 
 I2I2 1 
 
 ) 
 
 r 
 
 2. 
 
 3373> 
 
 0. 
 
 i 
 
 29 
 
 .301 
 
 0. 
 
 95900 
 
 530 
 
 .26 
 
 232. 
 
 96 
 
 26. 
 
 592 
 
 10. 
 
 
 
 27 
 
 .801 
 
 0. 
 
 94652 
 
 507 
 
 53 
 
 233- 
 
 13 
 
 25- 
 
 231 
 
 34 
 
 20 
 
 24 
 
 .16 
 
 o. 
 
 91491 
 
 
 .16 
 
 233. 
 
 22 
 
 21 . 
 
 926 
 
 TABLE 43. Ethyl 
 
 acetate.* 
 
 M 
 
 = 
 
 87.8 
 
 T c = 250.1 Young, 7 w( 
 
 I2I2\ 
 
 3373/ 
 
 0. 
 
 I 
 
 27 
 
 94 
 
 0. 
 
 92421 
 
 581 
 
 71 
 
 254- 
 
 97 
 
 25- 
 
 175 
 
 34- 
 
 6 
 
 23 
 
 375 
 
 0. 
 
 88277 
 
 501 
 
 .68 
 
 255- 
 
 23 
 
 21 . 
 
 062 
 
 60. 
 
 5 
 
 20 
 
 .064 
 
 0. 
 
 85019 
 
 441 
 
 63 
 
 255- 
 
 44 
 
 18. 
 
 078 
 
 1 Palewski, Ber. Chem. Ges., 15, 1882, p. 2463. His results are prob- 
 ably for the same ester as was used in this investigation. 
 
 *K used for calculation of 7 was 2.106, being the mean of that of 
 R. & S. and R. & G. 
 
22 
 
 TABLE 44. Propyl acetate. 
 
 (2 1 2 1 2 \ 
 J 
 ' O\3 / O/ 
 
 D.W. d. 
 
 o.i 28.433 0.91000 659.98 288.47 25.804 
 
 34.6 24.148 0.87229 576.55 287.32 21.914 
 60. I 21.208 0.84345 517-83 287.74 19.246 
 
 TABLE 45. Methyl propionate. 
 M = 87.8. T c = 257.4 Young. r - 
 
 10. o 27.944 0.92678 580.70 264.44 25.360 
 34.65 24.687 0.89758 524.08 264.87 22.405 
 59.75 21.499 0.86682 467.11 264.59 19-511 
 
 TABLE 46. Ethyl propionate. 
 M = 101.77- Tc = 272.9 Young. r = ^(2.3373) 
 
 10.0 27.043 0.90106 631.86 286.32 24.543 
 33.89 24.152 0.87435 575-74 286.21 21.919 
 59.15 21.194 0.84502 516.87 286.28 19.234 
 
 TABLE 47. Methyl isobutyrate. 
 M = 101.77- T c = 267. 55 Young. r = ^(2.3373) 
 
 00. o 26.619 0.90033 622.30 282.24 24.158 
 33.87 23.740 0.87328 566.39 282.19 21.545 
 
 10. i 20.634 0.84295 504.03 281.74 18.726 
 
 TABLE 48. Methyl butyrate. 
 M = 101.77- Tc = 281.3 Young, 2 3373 
 
 10. o 27.92 0.90925 648.44 293.42 25.338 
 34.8 24.915 0.88175 590.62 293.68 22.610 
 59.85 21.964 0.85375 53 x -99 293.45 I9-932 
 
SUMMARY. 
 As a result of this investigation we have shown : 
 
 1. That the drop weight method, in connection with the 
 new definition of normal molecular weight of Morgan, is the 
 most accurate method known for the determination of molec- 
 ular weight in the liquid state. 
 
 2. That the surface tension of a liquid may be most easily 
 and exactly calculated by this method, and that a knowledge 
 of density of the liquid is unnecessary, a factor which may be 
 responsible for some of the poor results which are found in the 
 literature. 
 
 3. That the definition of normal molecular weight in the 
 liquid state, i. e., such a liquid that it will give the same value 
 of T c at all temperatures of observation, shows that all the 
 above liquids with the exception of the formates, are non- 
 associated, i. e., normal in molecular weight, and that the 
 formates undergo a reversible reaction at higher temperatures, 
 which makes them appear abnormal. 
 
BIOGRAPHY. 
 
 Frederick William Schwartz was born in Albany, N. Y., 
 September 2, 1883. He entered the Rensselaer Polytechnic 
 Institute at Troy, N. Y., in 1901, and graduated in 1905 with 
 the degree of B.S. He attended Columbia University during 
 the summers of 1908, 1909, 1910 and also from September, 
 1910. Since graduation from Rensselaer he has been assistant 
 in chemistry at Rensselaer. 
 
. 
 
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