Isothermal vapor-liquid equilibria for 1,1,1,2-tetrafluoroethane plus propane and propane plus 1,1,1-trifluoroethane at 283.18 K

Isothermal vapor-liquid equilibria (VLE) for the binary systems 1,1,1,2-tetrafluoroethane (R134a) + propane (R290) and propane + 1,1,1-trifluoroethane (R143a) were measured at 283.18 K using a recirculation apparatus in which the vapor phase was forced through the liquid. The phase composition at equilibrium was measured by gas chromatography, calibrating its response using gravimetrically prepared mixtures. The data were correlated using the Carnahan-Starling-De Santis and Peng-Robinson equations of state. We found positive homoazeotropes for R134a (1) + R290 (2) at a pressure P = 1000.5 kPa and a composition x(1) = 0.386, and for R290 (1) + R143a (2) at P = 796 kPa and x(1) = 0.363. For the R134a + R290 there was a valid consistency with the values reported in the literature.