P rho Tx measurements for gas-phase pentafluoroethane plus propane mixtures by the Burnett method

In some refrigeration-based applications, hydrocarbons (HCs) are expected t o be promising long-term alternative refrigerants because of their zero ozo ne depletion potential (ODP) and negligible global warming potential (GWP) values. But there exists a serious disadvantage that they are flammable. De spite their flammability, however, commercial demands for HCs are increasin g not only in several European countries but also in southeast Asia. On the other hand, the flammability is considered a major issue in U.S.A. and Jap an. To suppress the flammability, blended mixtures of HCs with nonflammable HFCs are considered. As one of such mixtures, pentafluoroethane (R-125) an d propane (R-290) mixtures are dealt with in the present study. Although th e thermodynamic properties of each single component have been studied rathe r extensively, there is no study reported on those of this binary system. A ccordingly, we have measured the gas-phase P rho Tx properties of the binar y R-125 (1) + R-290 (2) system by using the Burnett isothermal -isochoric c oupling method. The present measurements cover an extensive range of temper atures (305 to 380 K), pressures up to 4.5 MPa, and densities up to 2.5 mol .dm(-3) for the binary systems with four different mole fractions of x(1) = 0.00, 0.29, 0.50, and 0.75, respectively. The present paper discusses the gas-phase P rho Tx properties for the first time regarding the present bina ry mixtures at their selected compositions.