A FLUCTUATION SOLUTION THEORY OF ACTIVITY-COEFFICIENTS - PHASE-EQUILIBRIA IN ASSOCIATING MOLECULAR SOLUTIONS

A new analytic statistical mechanical fluctuation solution theory for activity coefficients in multicomponent mixtures is developed. This theory is based on the newly formulated exact relations among the mixture direct correlation function integrals and the closures for cross direct correlation function integrals. One major advantage of this theory is its independence from the nature of intermolecular interaction potentials in solutions which are generally unknown for complex molecules. The theory is successfully used for vapor-liquid equilibria, liquid-liquid equilibria, and phase splitting prediction and correlation of fluid mixtures consisting of polar and associating molecules. © 1990 American Chemical Society.