Alternative refrigerants HFC-152a (CHF2CH3), HFC-143a (CF3CH3), HFC-134a (C
F3CH2F), and HCFC-142b (CF2ClCH3) are modeled as a dipolar two-center Lenna
rd-Jones fluid. Potential parameters of the model are fitted to the critica
l temperature and vapor-liquid equilibrium data. The required vapor liquid
equilibrium data of the model fluid are computed by the Gibbs-Duhem integra
tion for molecular elongations L = 0.505 and 0.67, and dipole moments mu*(2
) = 0, 2, 4, 5, 6, 7, and 8. Critical properties of the model fluid are est
imated from the law of rectilinear diameter and critical scaling relation.
The vapor liquid equilibrium data are represented by Wagner equations. Comp
arison of the vapor liquid equilibrium data based on the dipolar two-center
Lennard-Jones fluid viith data from the REFPROP database shows good-to-exc
ellent agreement for coexisting densities and vapor pressure.