Measurement of vapor–liquid equilibria for the binary mixture of propylene (R-1270) + 1,1,1,2-tetrafluoroethane (HFC-134a)

Isothermal vapor–liquid equilibria data for the binary mixture of propylene (R-1270) + 1,1,1,2-tetrafluoroethane (HFC-134a) at five equally spaced temperatures between 273.15 and 313.15 K were measured by using a circulation-type equilibrium apparatus. The experimental data were correlated with the Peng–Robinson equation of state (PR-EOS) combined with the Wong–Sandler mixing rule. It was confirmed that the data calculated by this equations of state had a good agreement with experimental data. ition, we used a simple equation obtained from the fundamental equation of phase equilibrium and NRTL activity coefficient model to approximately evaluate the azeotropic points of this mixture at investigated temperatures. A small difference between experimental azeotropic points and calculated ones corresponding to non-randomness parameter α equal to 0.2 was found.