MIXTURES OF N-ALKANES FROM THE PERTURBATION-THEORY OF ANISOTROPIC MOLECULE FLUIDS

Perturbation theory of the Kihara convex molecule fluids was applied t o determine the excess thermodynamic functions of several binary mixtu res of n-alkanes with various differences in chain length of the const ituents. The second-order perturbation expansions for the Helmholtz fu nction and compressibility factor were used to evaluate the excess the rmodynamic functions at zero pressure employing the Kihara pair potent ial with parameters epsilon/kT, sigma and L taken from the data set ob tained previously for pure n-alkanes. Fair agreement with experimental data was obtained for mixtures of lower n-alkanes only if the correct ion factor to the Lorentz-Berthelot combining rule for epsilon(12) was considered.