1.06; by the relationship (bC,/bp)~ = -T(d2P/ d P ) . Adding thie to Weltner gnd Pitzer's value
for C", (11.57) gives 12.6 to be compared with the value 12.5 of this research. TABLE I11 HEAT CAPACITYOF BENZENE-CARBON TETRACHLORIDE MIXTURES AT 750 MM. AND 373 "K Mole % CClr
0 00 24 48
50 80 74 80 100 00 HhAI C.4PACITP Mole
(
alcohol
0
350
380 410 440 Temperature, OK. Fig. 2.-Heat capacity of n-butyl (A), isobutyl (B), s-butyl (C), t-butyl ( D ) and n-amyl (E) alcohols a t 750 mm.: O?, this research; A , Reynolds and De Vries; A, Bennewitz and Rossner.
rqole-I deg.-', can be compared with data given by Weltner and Pitzer13for methyl alcohol. By using their expression for the second virial coefficient, P, the difference between Cp of the unassociated vapor at one atmosphere and C0, was calculated to be [ C(OSTRIBUTI0N
SO.
33
FROM THE 'rHERMODYNAMICS
10 20 25 30 41 50 60
Cp(exptl )
35 25 24 23
80 02 03 06
Cp(calcd )
Deviation
-0 10 - 03 - 04
24.92 23 97 23 10
22 19
OF
TABLE IV ALCOHOL-CARBON TETRACHLORIDE MIXTURES
CHaOH (35Z'K 1
C, in cal. male-4 deg. -1
CzHsOH
(355OK.)
23 02 21 22 20 38
22 IO 21 69 21 36
19 52
17 64
20 20 20 20
16 83 16 30
22 26 25 50
23 78 22.20
89 82 84
21 66
98
-r
21 12
10
80 100
21 .oa
For ethyl alcohol the values 16.a1 and 20.54 were calculated for C, of the unassociated vapor a t one atmosphere a t 3Fj5 and 437"R., respectively. There are no Cap values with which these can be coppared. LAFA'IETTE, INDIAXA
LABORATORY, PETROLEUM EXPERIMENT STATION, BVRE4U
OF MINES]
The Thermodynwnic Properties of 2-Methyl-2-propanethiol from 0 to 100QQK,l BY J. P. MCCULLOUGH, D. W. SCOTT, H. L. FINKE, IV.N. HUBBARD, &I.E. GROSS,C. KATZ,R. E. PENNINGTON, J. F. MESSERLY AND GUYWADDINGTON ~QCEIVED DECEMBER 3 , 1952
Various thermodynamic properties of solid, liquid and gaseous Z-methyl-Z-gro~~netbiol were measure4 from 12 to 450 "K. The data that were obtained are: heat capacity of the solid (12-274°K ); h q t s of transition, 972.0, 154.9 and 232.0 cal. mole-1 a t 151 6, 157 0 and 198.4 O K , respectively; heat of fusion, 593 2 cal mole-' a t the trtpk poiat, 274.42OK.; hest capaaity of the liquid, Csstd= 28 57 f 4.005 X lo-* p f 4 500 X lo-' p,cal. Ckg -'mOk-4 (27k33Q*KK.)r;ent€Q@y0f tk0 saturated liquid a t 298 16°K , 58 90 cal deg - 1 mole-', entropy of the ideal gas a t 298 16°K. and unit fugacity, 80.79 cal deg.-' mole-'; vapor pressure from 22 to 99", log,i$ (mm ) = 6 78781 - 1115 365/(t f 8 1 314); heat Qf vaporization, AH, = 9699 - 2 221 T - 0 01891 T2, cal mole-' (298-337'K ), heat capacity of the ideal gas, C; = 2 38 f 0.10229 T - 4 516 X 10-5 T*,cal deg - 1 mole-' (326-480°K 1, the second virial coefficient, B = ( P V - R T ) / P = -592 - 16.6 exp( 120WT),CE mole-' (2BS-45€hPK }; and the standard heat of formatton of the liquid from graphite, hydrogen and rhombic sulfur, AH* = -&3 78 kcal mole-' (298 10°K ) These thermodynamic data were used with available spectroscopic and molecular-structure information to compute the following chemical thermodynamic properties at selected temperatures Sa, C,: AH;, AFP and loglok'r from 0 to 1000°K : ( F " - H : ) / T , ( H " - H , ) / T , ( N o- Ht),
An integrated experiIrierita1 and computational program is conducted in this Laboratory to obtain thermodynamic data for organic sulfur compounds i I ) rhls mvestig-dtiou W a a performed as p u t
