Wilson parameters were estimated from solubility parameters and molar volumes. Namely, the interaction parameters due to attractive forces were evaluated from the solubility parameters and molar volumes predicted by the group contribution method of Fedors. The vapor-liquid equilibria (VLE) of typical polar mixtures such as ethanol + hydrocarbon systems were correlated by use of these Wilson parameters, in which the interaction parameters between unlike pairs were adopted. The interaction parameters were determined by using VLE data and were correlated with the difference in cohesive energy densities of the two pure components.Estimation of Wilson Parameters from Solubility Parameters and Molar Volumes