Thermophysical properties of low-density pure alkanes and their binary mixtures calculated by means of an (n-6) Lennard-Jones temperature-dependent potential

Self-consistent calculations of interaction pVT-virial coefficients B-12(T), viscosities eta(mix) (T), and diffusion coefficients D-12(T) of binary mixtures of the alkanes CnH2n + 2 (n < 6) are presented. This study is based on the recently developed model of the (n-6) Lennard-Jones temperature-dependent potential (LJTDP) and uses already obtained potential parameters of the pure alkanes as input data. The well-known and simple Lorentz-Berthelot (LB) and the more laborate Tang-Toennies (TT) mixing rules are applied to the potential parameters of the pure alkanes in order to determine those of the mixtures. The new Hohm-Zarkova-Damyanova (HZD) mixing rule, which is an extension of the TT-mixing rule, is also considered. The HZD takes into account that for the LJTDP model, in general, the repulsive parameter is an independent variable whose value n not equal 12. As in a recent examination of binary mixtures of globular molecules, the LB-mixing rule is superior to TT- and HZD-mixing rules when calculating equilibrium properties such as B-12(T). For the transport properties eta(mix)(T) and D-12(T), the new mixing rule performs slightly better.