Isothermal vapor–liquid equilibria for the pentafluoroethane + propane and pentafluoroethane + 1,1,1,2,3,3,3-heptafluoropropane systems

A new circulation-type vapor–liquid equilibrium (VLE) apparatus was developed, and two binary systems of pentafluoroethane (R125) + propane (R290) and pentafluoroethane (R125) + 1,1,1,2,3,3,3-heptafluoropropane (R227ea) were measured. The estimated uncertainties of the measured data are ±0.005 K for temperatures, ±600 Pa for pressures, and ±0.001 for mole fractions for both the liquid and vapor phases. The VLE data for the R125 + R290 system were used to validate the experimental setup by comparing with the literature ones. The experimental VLE data for the two measured systems were correlated using the Peng–Robinson equation of state with the classical mixing rules. The two systems were further described using predictive model.