A MODIFIED UNIQUAC MODEL THAT INCLUDES HYDROGEN-BONDING

Based on the association theory of Wertheim, a UNIQUAC association (UN IQUAC-A) model has been developed in which the hydrogen bond is treate d as a strong interaction rather than as a chemical reaction. Compared with the original UNIQUAC model, the UNIQUAC-A model results in bette r correlations of binary vapor-liquid equilibrium data for self-associ ating mixtures containing either an alcohol or an acid. However, both the UNIQUAC and UNIQUAC-A models produce small errors in pressure and vapor-phase mole fractions for cross-associating mixtures. We report i nteraction parameters and association parameters for the UNIQUAC-A mod el that can be used for the extrapolation and prediction of the binary vapor-liquid equilibrium in associating mixtures.