Bubble point pressure for binary mixtures of propane and pentafluoroethane

Bubble point pressure of the binary mixture of propane (C3H8) and pentafluoroethane (CHF2CF3) were measured by an acoustic absorption technique. The measurements were carried out in a wide temperature range of 243.15–333.15 K with an uncertainty within ±20 kPa except those in the propane rich and high temperature regions, which showed the strong absorption of acoustic wave. For (1−x)C3H8 + xCHF2CF3, the bubble point pressures increase sharply at first with increasing composition, x and then decrease indicating a convex curve through a small peak around x=0.65 corresponding to the azeotrope in the whole temperatures. The results were correlated by the Peng–Robinson (PR) equation of state including the azeotropic point.