Correlation of liquid-liquid equilibria for alcohol/hydrocarbon mixtures using the CPA equation of state

A recently developed equation of state, which combines the physical term of the classical SRK EoS with the association term based on the perturbation theory of Wertheim, called the Cubic Plus Association Equation of State (CPA EoS) (Kontogeorgis et al. [1]), is applied to liquid-liquid equilibrium (LLE) calculations in alcohol/hydrocarbon mixtures. The CPA EoS performs very well in all cases using the conventional van der Waals one-fluid mixing rules in the parameters of the physical term and a temperature-independent interaction parameter. The performance of the CPA EoS is compared to that of the conventional SRK EoS and UNIFAC models, and with another association model, the ESD EoS of Suresh and Elliott [2]. The CPA EoS gives much better results than the two conventional models and results comparable to those obtained with the ESD model. (C) 1997 Elsevier Science B.V.