Vapor–Liquid Equilibria of Alternative Refrigerants by Molecular Dynamics Simulations

Alternative refrigerants HFC-152a (CHF2CH3), HFC-143a (CF3CH3), HFC- 134a (CF3CH2F), and HCFC-142b (CF2ClCH3) are modeled as a dipolar two-ceInter Lennard-Jones fluid. Potential parameters of the model are fitted to the critical temperature and vapor-liquid equilibrium data. The required vaporliquid equilibrium data of the model fluid are computed by the Gibbs-Duhem iIntegration for molecular elongations L = 0.505 and 0.67, and dipole moments u*2 = 0, 2, 4, 5, 6, 7, and 8. Critical properties of the model fluid are estimated from the law of rectilinear diameter and critical scaling relation. The vaporliquid equilibrium data are represeInted by Wagner equations. Comparison of the vapor-liquid equilibrium data based on the dipolar two-ceInter Lennard- Jones fluid with data from the REFPROP database shows good-to-excellent agreement for coexisting densities and vapor pressure.