Vapor-Liquid Equilibria of the Trifluoromethane-Trifluorochloromethane System

Vapor-liquid equilibrium data weee determined by the vapor recirculation technique for the trifluoromethane-trifluorochloromethane binary at 31.9, -0.1, -55.1, and -100.05°F over the full range of composition. The compositions of the maximum-pressure (minimum-boiling) azeotrope exhibited by this system are 0.656, 0.630, 0.579, and 0.533 mol fraction CHF3, respectively, at pressures of 400.6, 247.1, 90.47, and 31.32 psia, respectively. The heats of vaporization of the azeotropes computed primarily from the equilibrium data, are 3639, 4723, 5845, and 6363 Btu/lb mol, respectively. Liquid-phase activity coefficients weee calculated from the experimental data under the assumption that the Redlich-Kwong equation of state gave an adequate description of the vapor phase. Subsequently, the Wilson equation was fit to these activity coefficients, and a correlation was developed which permits the vapor-liquid equilibria to be computed for any temperature between 32 and -100±F. © 1971, American Chemical Society. All rights reserved.