Statistical Thermodynamics of Associated Solutions

Abstract

Thermodynamic data for the solutions chloroform+benzene, acetone+chloroform, ethanol+chloroform, ethanol+acetone, and ethanol+ether are discussed in the light of a model for associated solutions which has been described previously. The theory in its original form, previously found satisfactory for solutions of alcohols in nonpolar solvents, proves satisfactory for the first two of these systems. To interpret the data for the remaining more complicated systems it is necessary to generalize the model to allow for interaction free energies which depend on temperature (presumably because of changes in vibration frequencies). The necessary generalization of the theory is described, and a consistent set of interactions for the ethanol systems is derived. The generalized theory should apply, with the limitations inherent in lattice theories, to most nonaqueous associated solutions.