CORRELATION OF HEATS OF MIXING DATA BY THE NRTL AND UNIQUAC MODELS .2. PREDICTIONS OF THE CALORIMETRIC PROPERTIES

Using heats of mixing data only, the temperature dependent parameters of the local composition models NRTL and UNIQUAC have been estimated and presented in the first part of this series. Here, these parameters are employed to predict the calorimetric properties: these are the heats of mixing h(E), partial molar heats of mixing at infinite dilution DELTA-H(i) and excess heat capacities C(p)E. Limiting activity coefficients are also estimated at different isotherms. All the predictions have been compared with experimental values. The NRTL and UNIQUAC models satisfactorily represent heats of mixing data at different isotherms for highly non-ideal and partially miscible systems. However, predictions in the region of high dilution are not always satisfactory, especially for associating mixtures. The values of C(p)E obtained from the differentiation of equations for h(E) are poor. Also, the predicted values of gamma(i) infinity show large deviations from the experimental values.