ISOTHERMAL VAPOR-LIQUID-EQUILIBRIA FOR 1,1,1,2-TETRAFLUOROETHANE PLUSPROPANE 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-trifl uoroethane (R143a) were measured at 283.18 K using a recirculation app aratus in which the vapor phase was forced through the liquid. The pha se composition at equilibrium was measured by gas chromatography, cali brating its response using gravimetrically prepared mixtures. The data were correlated using the Carnahan-Starling-De Santis and Peng-Robins on 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 th e R134a + R290 there was a valid consistency with the values reported in the literature.