Simultaneous description of vapour-liquid equilibria and excess enthalpy data in a wide temperature range and the prediction of vapour-liquid equilibrium data at high temperatures and pressures from excess enthalpy data with the help of a single isotherm at a low temperature are investigated by using a cubic 3-parameter equation of state more suitable for process calculations than 2-parameter versions because of a better common representation of vapour pressures, densities and other related data. Two g(E)-mixing rules in which the NRTL-equation is adopted are used for this purpose. The necessary temperature dependence of the model parameters is studied in detail and the simultaneous representation of the excess volume is examined. (c) 2007 Elsevier B.V. All rights reserved.