MEASUREMENTS OF THE CRITICAL PARAMETERS AND THE VAPOR LIQUID COEXISTENCE CURVE IN THE CRITICAL REGION OF HCFC-123

Measurements of the vapor-liquid coexistence curve in the critical region were made for HCFC-123 (CHCl2CF3) by visual observation of the vapor-liquid interface in an optical cell. Thirty densities of both saturated liquid and vapor were obtained in the range of temperatures from 401 K to the critical temperature corresponding to the density range between 203 and 1141 kg/m3. The experimental uncertainty of the temperature measurements was estimated to be less than ±12 mK, while that of the density measurements was estimated to be between ±0.09% and ±0.53%. Not only the level where the meniscus disappeared but also the intensity of the critical opalescence were considered for the determination of the critical temperature Tcand the critical density ρcof HCFC-123 as 456.86 ± 0.02 K and 556 ± 3 kg/m3, respectively. The critical exponent β was also determined, and the correlation of the saturated liquid density of HCFC-123 was established. © 1990, American Chemical Society. All rights reserved.