NOTES
880
with the dehydration of the compound to form sodium oleate. The low total heat of fusion of sodium oleate as compared to the sodium soaps of saturated fatty acids has been discuped by Vold'; the third analysis of sodium 12-hydroxystearate (Fig. 1,3) also resembles the thermogram shown in Vold's paper more than the initial thermogram (Fig. 1,l). The thermogram of lithium 12-hydroxystearate is shown in Fig. 2. The sharp peaks of the pure N 2
Fig. 2.-Thermogram
0 r.
of lithium 12-hydroxystearate.
lithium soap4 condense into a single diffuse peak in the case of the lithium hydrocastorate (Fig. 3),
Vol. 62
the liquid-vapor equilibria for the system nitrobenzene-t-butyl alcohol. Experimental Materials.-Eastman Kodak No. 820 t-butyl alcohol was distilled from calcium oxide after refluxiqg for 12 hours. The middle portion boiling a t 82.8" and having a refractive index 1.3877 a t 20" was used. Eastman Kodak No. 387 nitrobenzene was distilled and the middle fraction boiling a t 210.9' and having a refractive index of 1.5529 at 20" was used. Procedure.-The determination of the liquid-vapor equilibrium data was carried out in a Colburn still.* The pressure was maintained at 760 mm. of mercury by means of a Cartesian manostat .s Temperature of the mixture in the equilibrium chamber was measured with a chrome1 us. alumel thermocouple in conjunction with a Leeds and Northrup Type K potentiometer. It was assumed when samples taken at ten minute intervals had the same reading on an Abbe refractometer equilibrium had been attained. The compositions of the samples were determined from a, refractive index-composition graph.
TABLE I VAPOR-LIQUIDEQUILIBRIUM DATAFOR NITROBENZENE-& BUTYL ALCOHOL 207.7 203.7 199.3 192.5 177.8' 167.2 145.5 130.3 119.3 110.0 100.0 94.8 92.8 90.5 88.3 86.4 84.6 83.7
of lithium hydrocastorate.
most probably because of the lower purity. Lithium 12-hydroxystearate has a total heat of fusion of about 10.5 kcal. per mole. Lithium hydrocastorate is the lithium soap of hydrogenated castor oil acids, which consist of 12-hydroxystearic acid and stearic acid in the ratio of 5.7:l. The soap also contains 9% glycerol. The lack of distinctness of the initial part of the peak makes the evaluation of the latent heat difficult, but it was estimated to be 10 to 11 kcal. per mole of soap. As in the case of the pure soap, the hydrocastorate appears to have an initial transition temperature of about 157 to 160'. (4) Prepared by E. R. White. This is the aame preparation an that used in work reported by Bondi, J . CoEZ. Sci., 6,458 (1950).
220 I
I
Liquid
Vapor
0.001 .002 .003 .006 .014 .015
0.110 .254 .322 .470 .672 .775 .910 ,943 .968 .977
.049
.075 .114 .160 ,219 ,307 .372 .464 .549 ,659 .736 ,884 I
I
I
I
.988
.992 ,994 .995 .997 .998
.999 ,999 I
I
I
I
I
200 180
' I
d 140 E-r
LIQUID-VAPOR EQUILIBRIA FOR THE SYSTEM NITROBENZENE-&BUTYL ALCOHOL BY F. F. MIKUS~ AND C. W. LAWLER Chemistry Department, Tezas College of Arts and Industries, Kinusuille, Texas Received March 13, 1068
As part of an investigation of the behavior of some ternary systems it was necessary to determine (1) General Electric Company, The Knolls Atomic Power Laboratory, Soheneotady, N. Y.
I
Experimental Data The data obtained are presented in Table I and also graphically in Fig. 1.
Temp., 'C.
Fig. 3.-Thermogram
L
120
100
80 0.2 0.4 0.6 0.8 1.0 Mole fraction t-butyl alcohol. Fig. 1.-Liquid-vapor equilibria for the system nitrobenzene-t-butyl alcohol. 0.0
(2) C. A. Jones. E. M. Shoenburn and A. P. Colburn. Ind. Eng. Chcm., 86, 666 (1943). (3) R. Gilmont ,Ind. Eng. Chem., Anal. Ed., 18, 633 (1946).
