Vapor-liquid equilibria for carbon dioxide + 1,1,1,2-tetrafluoroethane (R-134a) systems at temperatures from 329 to 354 K and pressures upto 7.37 MPa

Vapor-liquid equilibrium state of carbon dioxide (CO₂) + 1,1,1,2-tetrafluoroethane (R-134a) mixture at 329.60, 339.10 and 354K and pressures upto 7.369 MPa have been measured in the whole range of compositions. Monophasic PvT properties were also determined for R-134a at temperatures from 313.13 to 342.9 K upto 25 MPa with an uncertainty lower than ±0.05%. The classical calibration method of the vibrating tube densimeter was used with N₂ and H₂O as reference fluids. The parameters of the Peng-Robinson equation of state (PR EoS) for both classical and Wong-Sandler mixing rules were fitted to experimental vapor-liquid equilibria at 329.60 K and used to predict the vapor-liquid equilibria at higher temperatures. Wong-Sandler mixing rules give better results than the classical mixing rules. The R-134a densities reported in this work were compared to the calculated values using the Tillner-Roth-Baehr EoS.