Lattice-model expressions for the combinatotial entropy of liquid mixtures: A critical discussion

Abstract

The basic assumptions, interrelations, performance and limitations of the various available expressions for the combinatorial entropy of liquid mixtures based on the lattice model are critically examined and compared. Explicit general expressions for the combinatorial entropy arising from Staverman's combinatorial factor are presented. The use of the Guggenheim-Staverman expression is recommended. When this expression fails to give physically meaningful results, the Flory-Huggins expression is recommended. The conditions under which the Guggenheim-Staverman expression gives unrealistic results are established. Methods for evaluating the pure component structural parameters are discussed and an unambiguous one studied in detail. © 1980.