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. . ' UNIVEESITY OF CALIFOENIA LIBBAEY, BEEKELEY THIS BOOK IS DUE ON THE LAST DATE STAMPED BELOW Books not returned on time are subject to a fine of 50c per volume after the third day overdue, increasing: to $1.00 per volume after the sixth day. Books not in demand may be renewed if application is made before expiration of loan period. FEB 29 1932 226927