AN APPROXIMATE NONRANDOM LATTICE THEORY OF FLUIDS - MIXTURES

A new approximate nonrandom lattice fluid model was derived and applie d to pure fluids in the previous paper[You et al., 1993a], in which an explicit expression for thermodynamic properties were obtained by exp anding Helmholtz free energy and the nonrandomness factor around the r eference athermal solution. In this work, the model was extended tb mi xtures and applied to density, to equilibria of vapor-liquid, vapor-so lid and liquid-liquid phases, to multiphase equilibria including UCST behaviors, and to heat of mixing for nonpolar/nonpolar, nonpolar/polar , and polar/polar binary mixtures of simple and complex molecules. Wit h two parameters for pure components and one binary interaction energy parameter, results obtained to date demonstrated that the mixture the ory is quantitatively applicable to a wide range of temperature, press ure and density.