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The (p, ρ, T) behavior of a refrigerant mixture of 50.00 mass% R1234yf and 50.00 mass% R290 was measured with the isochoric method. Along the six isochores (60, 121, 305, 500, 550, and 600 kg·m–3), a total of 40 single-phase (p, ρ, T) data points were obtained at temperatures from 330 to 400 K and pressures up to 6.6 MPa. In addition, the phase boundary of this mixture was experimentally investigated by visual observation of the vapor–liquid meniscus, and a total of 17 saturated densities and the critical parameters were obtained. Additionally, five saturated densities were also determined from the inflection points of the isochores. According to the multifluid approximation approach, a thermodynamic mixture model was formulated for R1234yf/290 mixtures. The parameters of the mixture model were determined by fitting the experimental data obtained in this work and those available in the literature. Expected uncertainties (k = 2) in calculated values with the mixture model are 0.2% for bubble and dew point pressures, 0.2% for liquid densities, 0.4% for vapor densities, 1% for saturated liquid and vapor densities, and 1.5% for isochoric heat capacities in the liquid phase. The mixture model can also be applied to regions away from the fitted experimental data with reasonable accuracy because it extrapolates well to higher temperatures and pressures, and to lower temperatures.

Measurements of PvT properties, saturated pressures, saturated densities, and critical parameters were carried out for R-13I1 (trifluoroiodomethane; CF 3 I). Forty-seven PvT property data in the one-phase region along seven isochores for R-13I1 were obtained in the temperatures between 310 and 405 K, pressures up to 6392 kPa, and densities between 48 and 1784 kg•m −3 using the isochoric method. Thirty-seven saturation pressure data for R-13I1 were obtained in the temperatures between 240 K and the critical temperature and pressures between 58 kPa and the critical pressure. Twenty-six saturated density data for R-13I1 were obtained by the observation of meniscus disappearance and the inflection points of the isochore in the densities between 48 and 1784 kg•m −3 . On the basis of these measurements, the critical temperature, critical density (critical molar volume), and critical pressure of R-13I1 were determined as T c = 396.495 ± 0.010 K (with a coverage factor, k = 2), ρ c = 865 ± 5 kg•m −3 (v c = 226.5 ± 1.3 cm 3 •mol −1 ) (bracketed interval), and P c = 3971 ± 3 kPa (with a coverage factor, k = 2), respectively. Moreover, a correlation for the saturation pressure and correlations for the vapor liquid coexistence curve were established by optimization techniques.

R-1132a is increasingly being considered as a low global warming potential component in alternative mixtures to R-23 in specialized low temperature and ultra-low temperature refrigeration systems. Though the thermodynamic properties of R-1132a were investigated in several studies up to 2018, reinvestigations have been carried out in recent years. In order to contribute toward these renewed measurements, the critical parameters of R-1132a were experimentally re-determined. Thirty-two vapor pressures from 240 K to the critical temperature, fifteen saturated vapor and six saturated liquid densities above 254 K and the PvT properties in both the vapor phase (98 points) and liquid phase (34 points) from densities of 50 kg·m −3 to 760 kg·m −3 were also measured. Specific correlations for each of these properties were optimized and compared to previously available data from the literature. Additionally, the Peng–Robinson equation of state was used to represent the aforementioned properties and further utilized to determine the enthalpy and entropy of R-1132a. Supplementary Information The online version contains supplementary material available at 10.1007/s10765-023-03184-4.