Prediction of hydrocarbon and CFC liquid mixtures densities

In this work, we apply an equation of state based on statistical-mechanical perturbation theory to liquid mixtures. Three temperature-dependent quantities are needed to use the equation of state (EOS): the second virial coefficient, B(T), effective van der Waals covolume, b(T), and a scaling factor, α(T). The second virial coefficients are calculated from a correlation that uses the heat of vaporization (e.g. Troutonʹs rule),ΔHvap, and the density at the triple point, ϱtp. α(T) and b(T) can also be calculated from the second virial coefficient by scaling. Based on the theory, all the three temperature-dependent parameters depend only on the repulsive branch of the potential function, and therefore, by our procedure, can be found from ΔHvap and ϱtp. It has considerable predicive power, since it only permits the construction of the P-v-T surface from the heat of vaporization plus triple-point density. The equation of state is tested for three-, four-, and five-component liquid mixtures.