Gas-phase PVT properties of 1,1,1,2,3,3-hexafluoropropane

We have measured the gas-phase PVT properties of 1,1,1,2,3,3-hexafluoropropane (R-236ea), which is considered to be a promising candidate for the replacement of 1,2-dichlorotetrafluoroethane (R-114). The measurements have been performed with a Burnett apparatus over a temperature range of 340-390 K and at pressures of 0.10-2.11 MPa. The experimental uncertainties of the measurements were estimated to be within ±0.5 kPa in pressure, ±8 mK in temperature, and ±0.15% in density. A truncated virial equation of state was developed to represent the PVT data and the second virial coefficients were also derived. The saturated vapor densities were also calculated by extrapolating the gas-phase isotherms to the vapor pressures. The critical density estimated from the rectilinear diameter was compared with the experimental value. The purity of the R-236ea sample used in the present measurements was 99.9 mol%.