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

The alkenes and cycloalkanes CmH2m. (m = I to 4) are important reactants, intermediates, and end products in the chemical industry. Some of them are also widely used in the polymer industry. This paper presents tables with recommended thermophysical data in the temperature range (200 to 1000) K and pressures <= 0.1 MPa of ethene, propene, cyclopropane, 1-butene, cis-2-butene, trans-2-butene, and iso-butene. Second pVT virial coefficients B, viscosities eta, and diffusion coefficients D are calculated by means of a (n-6) Lennard-Jones temperature-dependent potential. The potential parameters, equilibrium distance R-m(T), and potential well-depth epsilon(T) are defined as functions of the temperature T by solving an ill-posed problem of minimization of the squared deviations between measured and calculated B, eta, and D, normalized to their experimental error. Tables with potential parameters as well as algorithms for calculation of the potential-dependent properties are given in this paper.