Extrapolation of VLE data and simultaneous representation of caloric and volumetric properties by means of a cubic 3-parameter equation of state

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 gE-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.