Phase Equilibria of Chlorofluorocarbon Alternative Refrigerant Mixtures. Binary Systems of Trifluoromethane + Isobutane at 283.15 and 293.15 K and 1,1,1-Trifluoroethane + Isobutane at 323.15 and 333.15 K

Isothermal vapor−liquid equilibrium data of the binary mixtures of trifluoromethane (HFC-23) + isobutane (R600a) and 1,1,1-trifluoroethane (HFC-143a) + isobutane have been measured at 283.15 and 293.15 K and at 323.15 and 333.15 K, respectively. The experiment was carried out with a circulation-type equilibrium apparatus with the measurement of temperature, pressure, and the compositions of the liquid and vapor phases. The experimental data were correlated with the Peng−Robinson equation of state using the Wong and Sandler mixing rules.