Abstract: The present paper explores the applicability of the perturbed-hard-chain equation of state for estimating vapor-liquid equilibria for solutions of CO2, CO, CH4, H2, N2 and Ar in polar solvents such as H2O and CH3OH. Related parameters thus calculated, from literature data, indicated that for mixtures consisting of polar compounds alone or of polar and nonpolar compounds, the adjustable parameters are all temperature-related, and should be computed from the polynomial equation: A computer program was formulated for the eight-component system, CH3OH-H2O-CO2-CO-H2-CH4-N2-Ar. The resulting simulation for the vapor-liquid separation in methanol production checked closely the flowsheet data of Lurgi, Speichim and Billingham.