GEQUAC, an excess Gibbs energy model describing associating and nonassociating liquid mixtures by a new model concept for functional groups

The physically founded excess Gibbs energy model, GEQUAC, allows the description of excess properties for associating as well as nonassociating liquid mixtures. This is achieved by explicitly accounting for different poles of molecular surface between which strong interactions take place in a mixture. In previous work, the model concept and the subsequent model equation were tested against results of Monte-Carlo computer simulations and proved the ability to describe g(E), h(E) and Ts-E of ketone + n-alkane and n-alcohol + n-alkane mixtures. This work provides model parameters fitted to binary isothermal VLE and hE data for the mixtures butanone + n-heptane, 1-butanol + n-heptane and butanone + 1-butanol as a first step in application. The model parameters show physical relevance and are used for prediction of isothermal VLE and hE data (own measurements) at 323 K of the ternary mixture butanone + n-heptane + 1-butanol. (C) 1999 Elsevier Science B.V. All rights reserved.