Viscosity, SecondpVTVirial Coefficient, and Diffusion of Binary Mixtures of Small Alkanes CH₄, C₂H₆, C₃H₈,n-C₄H₁₀,i-C₄H₁₀,n-C₅H₁₂,i-C₅H₁₂, and C(CH₃)₄Predicted by Means of an Isotropic Temperature-Dependent Potential

Abstract

The isotropic (n-6) Lennard-Jones temperature-dependent potential (LJTDP) together with the Hohm−Zarkova−Damyanova mixing rules is used to predict second interaction pVT virial coefficients B AB(T), interaction viscosities ηAB(T), and diffusion coefficients D AB(T) for all 28 binary mixtures of the alkanes CH4, C2H6, C3H8, n-C4H10, i-C4H10, n-C5H12, i-C5H12, and C(CH3)4 at low densities. Where possible, the obtained equilibrium and transport data are compared to existing measurements. In general, good agreement is found between experiment and theory. On the basis of these findings, fitting formulas and tables are presented which allow for a fast and reliable estimation of the aforementioned properties in the temperature range between (180 and 1200) K.

Effective (n-6) Lennard-Jones Potentials with Temperature-Dependent Parameters Introduced for Accurate Calculation of Equilibrium and Transport Properties of Ethene, Propene, Butene, and Cyclopropane

“…Assuming that the attractive dispersion-interaction does not depend on the temperature, the potential well-depth for the interaction between two equal particles is given by ε ( T ) = ε ( 0 ) false[ R m ( 0 ) / R m ( T ) false] 6 Within our model and the considered maximum temperature of 1100 K, this is a reasonable assumption. By using the ( n -6) LJTDP, the second pVT virial coefficient B , the viscosity η, and the diffusion coefficient D can be calculated via standard formulas which are given, e.g., by Hirschfelder et al or more condensed by Zarkova et al, where the case of binary mixtures is also considered.…”

“…The LJTDP has been successfully applied before to a number of pure gases like the alkanes , and perfluoroalkanes . We have shown that it performs also very well in the prediction of B , η, and D of binary mixtures of alkanes and other gases. , To give a comprehensive overview on the molecules with sum formula C m H 2 m , we not only consider the alkenes but also try to include the two cyclic compounds cyclopropane (C 3 H 6 ) and cyclobutane (C 4 H 8 ) in our studies. These two molecules are also of some importance in industry − and basic research …”