Calculation of infinite dilution activity coefficients by the NRTL and UNIQUAC models

Infinite dilution activity coefficients have been calculated for 42 binary systems using the NRTL and UNIQUAC models. Temperature dependent parameters of the models are used in the calculations. These parameters have been estimated by using excess Gibbs free energy and enthalpy of mixing data simultaneously. The calculated values are compared with experimental infinite dilution activity coefficients obtained by extrapolation of vapor‐liquid equilibrium (VLE) data published in the literature. The agreement between the calculated and experimental values is poor for highly nonideal system. The selection of the best model is difficult and may be system dependent.