Phase Equilibria of CFC Alternative Refrigerant Mixtures: 1,1,1,2,3,3,3-Heptafluoropropane (HFC-227ea)+Difluoromethane (HFC-32), +1,1,1,2-Tetrafluoroethane (HFC-134a), and +1,1-Difluoroethane (HFC-152a)

Isothermal vapor liquid equilibria were measured for the binary systems difluoromethane (HFC-32)+1,1,1,2,3,3,3-heptafluoropropane (HFC-22ea) and 1,1-difluoroethane (HFC-152a)+1,1,1,2,3,3,3-heptafluoropropane at 283.15 and 303.15 K and 1,1,1,2-tetrafluoroethane (HFC-134a)+1,1,1,2,3,3,3-heptafluoro- propane at 303.15 and 323.15 K in an apparatus in which both phases were recirculated. The experimental data were correlated with the Peng Robinson equation of state using the Wong Sandler mixing rules. Azeotropic behavior has not been found in any of the three mixtures.