A Thermodynamic Approach for Predicting Physical-chemical Properties

Since the beginning of physical chemistry, tens of thousands of articles have been written in order to understand the behavior of fluid mixtures. Although there is no general theory on the properties of fluid mixtures, a large number of theories and models whose area of application is restricted to a particular type of mixture are available. The Gibbs free energy is a function of the mole fractions of the different constituents of the mixture. A first approach consists therefore of writing a limited expansion of this function and, according to the order of the expansion, the Margules, Redlich-Kister or Van Laar equations appear. However, although series expansion is very flexible, (1) it does not explain physical and chemical phenomena occurring in a mixture and (2) it has mainly no predictive power since the phase transition of binary mixtures to ternary mixtures requires the adjustment of additional parameters.