MEASUREMENTS OF THE (PRESSURE, DENSITY, TEMPERATURE) RELATIONS OF DICHLORODIFLUOROMETHANE (R12) AND OF CHLORODIFLUOROMETHANE (R22) IN PARTS OF THE HOMOGENEOUS GAS AND LIQUID REGIONS AND OF THE COEXISTENCE CURVE

Measurements of (P gr, T) for pure dichlorodifluoromethane (R12) and for pure chlorodifluoromethane (R122) were carried out on four isotherms (150 K, 200 K, 250 K, and 300 K) in the homogeneous liquid region from the vapour pressure up to pressures of 8 MPa. Measurements in the homogeneous gas region were performed on three isotherms (260 K, 300 K, and 330 K) for R 12 andon four isotherms (250 K, 270 K, 300 K, and 330 K) for R 22 up to the corresponding vapour pressure. Furthermore, the saturated-liquid densities of R12 and of R22 were measured in the temperature range from 120 K to 340 K along with the vapour pressure; the vapour-pressure measurements, however, were started only at 180 K. Using the experimental results from the gas region, the saturated-vapour densities and the second virial coefficients were also determined. The uncertainties of the homogeneous liquid densities and of the saturated-liquid densities were estimated to be <|0.0002 · ρ| and the uncertainties of the gas densities ρ > 10 km · m-3 to be <|.0003 · ρ|. The new measurements are compared with the experimental results of previous workers. © 1992 Academic Press Limited All rights reserved.