Volumetric properties under pressure for 1-fluoro-1,2,2-trichloroethane (R131) and 1,1-difluoro-1,2,2-trichloroethane (R122)

Abstract

The effect of pressure on the volume of R131 and R122 is reported for six temperatures covering the range 278.15 to 338.13 K and pressures up to 380 MPa. Densities at the same temperatures have been measured at atmospheric pressure for each liquid. The experimental data have been used to calculate isothermal compressibilities, thermal expansivities, and internal pressures: the change in isobaric heat capacity from its value at atmospheric pressure has also been estimated. The modified Tait equation has been used to show that the volume ratios for both compounds can be combined with those for R123 (2,2-dichloro-1,1,1-trifluoroethane) and represented by a common equation.