Corresponding states treatment of refrigerants and cryogenic fluids

An analysis of temperature dependence of saturated liquid density along the liquid vapour coexistence curve shows that a plot of reduced properties Tr(=T/Tc) against Trρ{variant}r (=Tρ{variant}/Tcρ{variant}c), goes through a maximum at a particular Tr for all the following liquids: Ne, Ar, Kr, Xe, N2, O2, CH4, C2H6, C2H4, CO2, R11, 12, 12B1, 13, 13B1, 14, 21, 22, 23, 32, 40, 113, 114, 115, H2O and NH3. For all these liquids, except NH3, Tr is ≈ 0.82, whether they are polar, non-polar, monoatomic or polyatomic. This characteristic temperature, T* (=TcTr), has been used to evaluate the energy parameter and the corresponding molar volume has been used to evaluate the length parameters for calculation of reduced critical properties. T* is also found to be a point of inflexion on the saturated liquid viscosity versus temperature plot. © 1985.