Gas phase PVTx properties for binary mixtures of HFC-161 and HFC-143a

An experimental study of the pressure–volume–temperature–composition (PVTx) properties in the gas phase for binary mixtures of ethyl fluoride (HFC-161) and 1,1,1-trifluoroethane (HFC-143a) was conducted in the range of temperatures from 308.138 to 403.205 K, pressures from 1077.3 to 4684.3 kPa, densities from 0.5144 to 2.0224 mol dm−3, and compositions from 0.3852 to 0.8703 mole fractions of HFC-161. The measurements were performed with an isochoric cell apparatus. The uncertainties in the present work were estimated to be ±1.5 kPa for pressure, ±6 mK for temperature, and ±0.15% for composition. On the basis of the experimental PVTx property data, a truncated virial equation of state was developed for the binary HFC-161/143a system. This equation reproduced the experimental data in the gas phase within ±0.247% in pressure and within ±0.254% in density.