Liquid-liquid equilibrium (LLE) data for ternary systems at both low and high pressures were well reproduced by the PRSV equation of state (EOS) with two Gibbs free energy-based equation of state (EOS-G(E)) mixing rules, called modified Huron-Vidal first order (MHV1) and Wong-Sandler (WS) mixing rules. The binary parameters, which were previously determined from only the Gibbs free energy models at each temperature and pressure in the literature, are utilized for the rules. Good predictions were obtained for the water + methanol + alkyl ether systems at low pressure and the water + alcohol + 1,1-difluoroethane (DFE) systems at high pressures. (c) 2004 Elsevier B.V. All rights reserved.