Prediction of vapor-liquid and liquid-liquid equilibria and thermodynamic properties of multicomponent organic systems from optimized binary data using the Kohler method

Abstract

Talley, P.K., Sangster, J., Bale, C.W. and Pelton, A.D., 1993. Prediction of vapor-liquid and liquid-liquid equilibria and thermodynamic properties of multicomponent organic systems from optimized binary data using the Kohler method. Fluid Phase Equilibria, 85: 101-128. The Kohler model permits the thermodynamic properties of multicomponent liquid solutions to be predicted from binary data. The model does not impose restrictions on the functional form of the binary Gibbs energy expressions, nor does it limit the number of adjustable binary parameters. The binary data can thus be fitted with high precision. A general polynomial expansion permits all types of binary data (vapor-liquid equilibria including total pressure data, liquid-liquid equilibria, excess enthalpy, excess heat capacity, etc.) from all sources to be optimized simultaneously to obtain one self-consistent expression for the excess binary Gibbs energy at all compositions and temperatures. The combination of the Kohler model and the optimization technique is shown to provide very good predictions of phase equilibria and thermodynamic properties in the methanol + ethanol + 2-propanone + trichloromethane quaternary system and its ternary subsystems, and in the benzene + ethanenitrile + heptane ternary system which exhibits liquid-liquid immiscibility.