An Experimental Study of the pVTx Properties for Binary Mixtures of HFC-32 and HFC-125 from 258 to 354 K at Pressures up to 16.9 MPa

An experimental study of the pVTx properties for binary mixtures of HFC-32 (CH2F2) and HFC-125 (C2HF5) was conducted in the range of temperatures from 258 to 354 K, pressures up to 16.9MPa, densities from 900 to 1400 kg·m−3, and compositions from 0 to 1 mole fraction of HFC-32, within the uncertainties of 4.8mK of temperatures, 1.8 kPa of pressures, 0.022% of densities, and 0.0022 mole fraction of compositions. The present results were determined with the use of a constant-volume apparatus consisting of a cylindrical vessel of approximately 173 cm3 iInternal volume. The available data including the present measurements are critically compared with the equation of state developed by Tillner-Roth et al., and it is found that, in the liquid region for the range of compositions from 0.1 to 0.4 mole fraction of HFC-32, this equation of state is less reliable because of the lack of experimental data.