Measurements of saturated densities and critical parameters for the binary mixture of 2,3,3,3-tetrafluoropropene (R-1234yf) + difluoromethane (R-32)

The vapor–liquid coexistence curves near the critical point of the binary mixture of 2,3,3,3-tetrafluoropropene (R-1234yf) + difluoromethane (R-32) were measured by means of the visual observation of meniscus disappearance. Eleven, eighteen, and eleven saturated densities were obtained for mixtures with 50.00 mass%, 80.01 mass%, and 90.00 mass% of R-1234yf, respectively. The critical temperatures, critical densities, and critical molar volumes of the mixtures were determined from the meniscus disappearing level and the intensity of the critical opalescence. The critical pressures of the mixtures were also determined from the analysis of pρTx measurements. The composition dependence of the critical parameters was formulated with simple correlations.