Vapour-liquid equilibria for the binary systems of pentafluoroethane {(R125) + 2,3,3,3-tetrafluoroprop-1-ene (R1234yf)} and {trans-1,3,3,3-tetrafluoropropene R1234ze(E)}

In this work, isothermal vapour-liquid equilibrium (VLE) data for the binary mixtures of pentafluoroethane (R125) + 2,3,3,3-tetrafluoroprop-1-ene (R1234yf) and trans-1,3,3,3-tetrafluoropene (R1234ze(E)) have been investigated. The experimental measurements were carried out by using the AnTLcirCapValVis analytical method over the temperature range from 283.15 K to 323.15 K. The standard uncertainties of temperature, pressure and mole fractions are 10 mK, 0.5 kPa and 0.005, respectively. The Peng-Robinson (PR) equation of state (EoS) and its modifications from Stryjek and Vera (PRSV and PRSV2) combined with Wong-Sandler (WS) mixing rule and the non-random two-liquid activity coefficient model (NRTL) were employed to correlate the parameters of binary mixtures, respectively. The PRSV2 + WS + NRTL model shows the best consistency with the experimental VLE data compared with the other two models (PR + WS + NRTL and PRSV + WS + NRTL). The average absolute relative deviation of pressure (AARD(p)) and average absolute deviation of vapour phase mole fraction (AAD(y)) are 0.10% and 0.0012 for R125 + R1234yf, 0.16% and 0.0014 for R125 + R1234ze(E), respectively. Both the experimental data and the calculated results imply that R125 + R1234yf and R125 + R1234ze(E) are zeotropic binary mixtures over the studied temperatures.