The application of the cubic-plus-association (CPA) equation of state has been extended to mixtures containing cross-associating compounds such as glycols and water. In this case, combining rules are required in the association term of CPA for the cross-association energy and volume parameters. Different types of such combining rules have been suggested over the past years for association models such as statistical associating fluid theory. These are tested in this work for CPA in terms of their correlation and prediction capabilities for vapor-liquid equilibria of glycol-water systems. Comparisons with the Soave-Redlich-Kwong equation of state are also provided. It has been found that the arithmetic mean combining rule for the crossassociation energy parameter and the geometric mean for the cross-association volume parameter provide overall the best results for cross-associating systems containing glycols and water. Moreover, preliminary results show that the CPA model can be used to predict multicomponent, multiphase equilibria for glycol-water-hydrocarbons based solely on binary interaction parameters.

The ability of the Unifac-FV and Entropic-FV models to predict phase equilibria for dendrimer systems is investigated in this work. Different approaches are considered for the estimation of the density of the dendrimers, which is required as input parameter in the free-volume models. The density is not always available for such polymers.The predictions obtained by the two models are compared with recent vapor-liquid equilibrium experimental data for dendrimer systems. It is shown in this study that both methods represent satisfactorily the experimental data in many cases, whereas Unifac-FV performs better for PAMAM dendrimers (where some of the interaction parameters are missing). However, Unifac-FV is the model that is most influenced by the dendrimer's density. Both models yield better results when experimental densities are employed (for AR dendrimers), but in those cases where such data are not available, predicted densities can be reliably obtained via the van Krevelen method (for C12 and A4 dendrimers).