Ti = temperature a t inner boundary To = temperature a t outer boundary
d A =ratio
of area of complete s p h e r e to t h a t of s p h e r e minus area intersected by s t e m
ACKNOWLEDGMENT W. M. DeWitt c o n s t r u c t e d t h e thermal conductivity c e l l , H. H. Reamer a i d e d materially i n obtaining t h e experimental r e s u l t s , and W. N. L a c e y reviewed t h e manuscript. LITERATURE CITED (1) Andrussow, L., 1. chim phys. 49, 599 (1952). (2) Bridgeman, 0. C . , J. Am. Chem. SOC.49, 1174 (1927). (3) Filippov, L. P., Vestnik Moskov. Univ. 8, No. 9, Ser. Fiz.Mat. i E s t e s t v e n . Nauk No. 6 , 109 (1953). (4) Ingersoll, L. R., Zobel, 0. J . , Ingersoll, A. C., "Heat Conduction," McGraw-Hill, New York, 1948. (5) Johnston, H. L . , Grilly, E. R . , J. Chem. P h y s . 14, 233 (1946). (6) Kannuluik, W. G., Martin, L. H., P r o c . Roy. SOC. (London) A 144, 496 (1934). (7) Keyes, F. G., T r a n s . Am. SOC.Mech. Engrs. 73, 589 (1951). (8) Zbid., 73, 597 (1951). (9) Zbid., 74, 1303 (1952).
(10) Ibid., 76, 809 (1954). (11) Keyes, F. G., Sandell, D. J . , J r . , Ibid., 72, 767 (1950). (12) Lenoir, J. M., Junk, W. A,, Comings, E. W., Chem. Eng. Progr. 49, 539 (1953). (13) Mason, H. L., Trans. Am. SOC.Mech. Engrs. 76, 817 (1954). (14) Meyers, C. H., J. R e s e a r c h , N a t l . Bur. Standards 9, 807 (1 932). (15) Reamer, H. H., Richter, G. N., Sage, B. H., 2nd. Eng.,Chem. 46. -, 1471 (1954L (16) Reamer, H. H., Sage, B. €I., Zbrd., 44, 185 (1952). (17) Reamer, H. H., Sage, B. H., R e v . Sci. Znstr. 24, 362 (1953). (18) Rothman, A. J., Bromley, L. A., 2nd. Eng. Chern. 47,899(1955) (19) Sage, B. H . , L a c e y , W. N . , Trans. Am. Znst. Mining Mer. Engrs. 136, 136 (1940). (20) Sakiadis, B. C . , C o a t e s , J e s s e , A.1.Ch.E. Journal 1 , 275 (1955). (21) Schlinger, W. G., Sage, B. H . , Ind. Eng. Chem. 42, 2158 (1950). (22) Sellschopp, W . , F o r s c h . G e b i e t e Ingenieurw. 5 8 , 162 (1934). (23) Ubbink, J. B., d e H a a s , W. J., P h y s i c a 10, 465 (1943). (24) Vargaftik, N . , Tech. P h y s . U.S.S.R.4, No. 5 , 341 (1937). ~
~
Received for review August 6, 1956.
Accepted November 23, 1956.
T h i s work w a s sponsored by P r o j e c t SQUID which is supported by t h e Office of N a v a l R e s e a r c h under Contract N6-ori-105, T. 0. III, NR-098-038. Reproduction in full or i n part is permitted for any u s e of t h e United S t a t e s Government.
Heat of Mixing of n-Amyl Alcohol and Benzene DANIEL ALJURE CHALELA', HARRY H. STEINHAUSER, AND JOEL 0 . HOUGEN' Rensselaer Polytechnic Institute, Troy, N.Y
T h e o b j e c t i v e of t h i s work w a s t o determine experimentally t h e h e a t of mixing of n-amyl a l c o h o l in b e n z e n e over a r a n g e of compositions. Such information is useful i n predicting thermodynamic p r o p e r t i e s of t h i s binary mixture, particularly in connection with d e v i a t i o n s from i d e a l behavior of vapor-liquid equilibrium r e l a t i o n s h i p s . B e c a u s e n-amyl alcohol i n pure form t e n d s to a s s o c i a t e through hydrogen bonding t o g i v e l i n e a r polymers, i t s h e a t of mixing with a n inert s o l v e n t , s u c h a s benzene, i s endothermic. T h i s corresponds t o t h e rupture of hydrogen bonds during dilution. Table
I. Heat of Mixing of n-Amyl Alcohol i n Benzene
Mole Fraction Benzene
AHa of Mixing a t 2OoC., Cal./Gram Mole
0.158 0.260 0.325 0.331 0.4 73 0.483 0.485 0.497 0.650 0.758 0.837 a A H = enthalpy of mixture -enthalpy of pure
91 126 183 177 214 219 213 212 223 208 177 components.
280
z
2 l-
3 240 J
0 v)
LL
0 200
w A
0
I
' 160 w K
v)
0
i0
120
I c3
f
E
80
I LL
0
l-
4c
a
w
I
0 'Present address, National University, Bogota, Colombia, S.A. +Present a d d r e s s , R e s e a r c h a n d Engineering Division, Monsanto Chemical Co., St. L o u i s , Mo.
66
INDUSTRIAL AND ENGINEERING CHEMISTRY
0 2
0 4
06
0 8
I O
BENZENE MOLE FRACTION Figure
1.
Heat of mixing of n-amyl alcohol in benzene
VOL. 2, NO. I
In c o n d u c t i n g microcalorimetric determinations i t i s of utmost importance t o obtain t h e pertinent m e a s u r e m e n t s i n s u c h a way t h a t s y s t e m a t i c and a c c i d e n t a l e r r o r s a r e elimin a t e d o r r e d u c e d t o a minimum. S o u r c e s of error may f a l l i n o n e of t h r e e groups: i n a d e q u a t e measurement of temperature, uncontrolled h e a t t r a n s f e r , and u n d e s i r a b l e s i d e rea c t i o n s occurring i n t h e s y s t e m being s t u d i e d . T h e u s e of comparative calorimetric t e c h n i q u e s m a k e s i t p o s s i b l e t o avoid or minimize t h e e f f e c t s of t h e s e s e c o n d a r y phenomena.
during mixing and heating, t h e e l e c t r i c a l energy input i s e q u a l t o t h e h e a t of mixing. Thiophene-free b e n z e n e and n-amyl aicohol were dist i l l e d i n a P o d b i e l n i a k column u s i n g a 100 t o 1 reflux ratio. T h e r e f r a c t i v e index at 25OC. of b e n z e n e differed by no more t h a n 0.00005 from 1.49800 during t h e d i s t i l l a tion (4). T h e v a l u e for amyl alcohol w a s 1.40815. A Beckmann thermometer w a s u s e d for t h e temperature measurements.
EXPERIMENTAL METHOD
RESULTS
T h e calorimeter w a s almost i d e n t i c a l t o that u s e d by Z e l l h o e f e r and C o p l e y (5) and by McLeod a n d Wilson (2). T h e method h a s b e e n u s e d by Audrieth and Steinmann (1) and by S p e n c e (3) for measuring exothermic h e a t s of solution. T h e method of s u c c e s s i v e comparative measurements w a s a d a p t e d i n t h i s work t o endothermic h e a t s of solution. T h e temperature c h a n g e from 2OoC. which occurred upon mixing of t h e t w o components w a s first measured. T h e n t h e m e a s u r e m e n t s w e r e r e p e a t e d following t h e introduction of a known q u a n t i t y of e l e c t r i c a l energy. T h e e n e r g y introduced i n t h e l a t t e r case w a s s u c h a s t o produce a temperature i n c r e a s e approximately e q u a l t o t h e temperature d e c r e a s e which occurred following t h e mixing reaction. T h u s , when appropriate a d j u s t m e n t s a r e made for h e a t l e a k s , for stirring, and for inequality of t h e temperature c h a n g e s
T h e experimental r e s u l t s a r e summarized i n T a b l e I and F i g u r e 1. T h e d a t a a r e s e e n t o b e reproducible within i 5%. T h e r e s u l t s o b t a i n e d are t y p i c a l of s u c h s y s t e m s and show, i n t h i s c a s e , a maximum molal heat of mixing of about 225 c a l o r i e s at 60 mole % of b e n z e n e .
1957
LITERATURE CITED (1) Audrieth, L. F., Steinmann, R., J . A m . Chem. S o c 63, 2115 ( 194 1). (2) McLeod, D. B., Wilson, F. J., Trans. Faraday SOC. 31, 596 (1935). (3) Spence, R. W . , J . P h y s . Chem. 45, 304 (1941). (4) Timmermans, J . , “Physico-Chemical Constants of Pure Organic Compounds,” Elsevier, New York, 1950. (5) Zellhoefer, G. F., Copley, M. J . , 1. Am. Chem. SOC. 60, 1343 (1938). Received for review August 9 , 1956. Accepted January 7, 1957.
CHEMICAL AND ENGINEERING DATA SERIES
67
