APPLICABILITY OF THE 2ND-ORDER PERTURBATION-THEORY OF ANISOTROPIC MOLECULE FLUIDS TO REAL SYSTEMS OF CONSTITUENTS DIFFERING IN MOLECULAR-SIZE AND OR POLARITY/

An overview of the recent results obtained from the full second-order perturbation theory of the anisotropic molecule fluid for real systems is given. The performance of the theory has so far been examined upon (i) a series of n-alkanes with the carbon number up to 16, modeled as fluids of the Kihara rod-like molecules, (ii) their binary mixtures, (iii) a series of low-molecular linear chlorinated hydrocarbons with t he carbon number up to 4, modeled as fluids of Kihara rods with assign ed dipole moments, and (iv) mixtures of the linear chloroalkanes with n-alkanes. Parameters of the interaction potential for the pure compou nds were evaluated from the data on the vapor-liquid coexistence regio n (namely the vapor pressure and saturated liquid density) of the real substances. Each of the parameters of the pair-potential for the pure n-alkanes is accurately represented as a function of the number of ca rbon atoms by a simple analytical expression. Using the conventional c ombining rules with only marginal corrections in the cross-terms, the excess Gibbs energies, excess enthalpies, and excess volumes as a func tion of both the composition and temperature are simultaneously repres ented succesfully for the n-alkane binaries and also for the chloroalk ane + n-alkane mixtures.