Vapor + liquid equilibrium measurements and correlation of the refrigerant mixtures Difluoromethane (HFC-32) +, and Pentafluoroethane (HFC-125) + 1,1,1,2,3,3-Hexafluoropropane (HFC-236ea) at 288.6, 303.2 and 318.2 K

Isothermal vaporliquid equilibria (VLE) for the binary systems of difluoro-methane (HFC-32)+1,1,1,2,3,3-hexafluoropropane (HFC-236ea) and penta-fluoroethane (HFC-125)+1,1,1,2,3,3-hexafluoropropane (HFC-236ea) were measured at 288.6, 303.2, and 318.2 K using an apparatus in which the vapor phase was recirculated through the liquid. The phase composition at equilibrium was measured by gas chromatography, based on calibration using gravimetrically prepared mixtures. Both systems show a slight deviation from Raoult's law. The uncertainties in pressure, temperature, and vapor- and liquid-phase composition measurements were estimated to be no more than +/-1 kPa, +/-0.02 K, and +/-0.002 mol fraction, respectively. The data were analyzed using the CarnahanStarlingDeSantis equation of state.