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2532671 
Journal Article 
The excess molar enthalpy of (benzene, or cyclohexane plus tetrachloromethane) (g), and (benzene, or cyclohexane plus chloromethane) (g) from temperatures 353.2 K to 423.2 K 
Parker, AP; Rieger, F; Johnson, PW; Wormald, CJ 
1998 
No 
Journal of Chemical Thermodynamics
ISSN: 0021-9614 
30 
8 
999-1010 
English 
WOS:000075623800007 
A flow-mixing calorimeter has been used to measure the excess molar enthalpy H-m(E) of (cyclohexane + tetrachloromethane)(g) and (benzene + tetrachloromethane)(g) at standard atmospheric pressure over the temperature range 353.2 K to 423.2 K. The non-ideality of the cyclohexane, benzene, and tetrachloromethane was fitted using the Kihara potential. Cross-terms were calculated using the equation epsilon(12) = (1 - k(12))(epsilon(11)epsilon(22))(1/2), and to fit the measurements on (cyclohexane + tetrachloromethane)(g) the value of (1 - k(12)) was 1.0005, while to fit the measurements on (benzene + tetrachloromethane)(g) the value of (1 - k(12)) was 0.996. This implies that the gas phase interaction between benzene and tetrachloromethane is slightly weaker than the interaction between cyclohexane and tetrachloromethane. In marked contrast to liquid phase H-m(E) measurements, no evidence of a specific interaction between benzene and tetrachloromethane was found. Second virial cross coefficients obtained from the measurements are in agreement with those obtained from (p, V, T).



Measurements of H-m(E) on (cyclohexane + chloromethane)(g) and (benzene + chloromethane)(g) were also made. The non-ideality of chloromethane was fitted using the Storvick-Spurling potential. The (cyclohexane + chloromethane)(g) measurements are well fitted using (1 - k(12)) = 0.88. The (benzene + chloromethane)(g) measurements were fitted using a quasi-chemical model which, for benzene-chloromethane association, yielded a value of the equilibrium constant K-12(298.15 K) = 0.179 MPa-1 and an enthalpy of association Delta H-12 = -(7.17 +/- 2) kJ . mol(-1). (C) 1998 Academic Press. 
excess enthalpy; second virial coefficient; gas mixture