MEASUREMENTS OF THE VAPOR-LIQUID COEXISTENCE CURVE AND DETERMINATION OF THE CRITICAL PARAMETERS FOR REFRIGERANT 114.

Measurements of the vapor-liquid coexistence curve in the critical region for Refrigerant 114 (C//2Cl//2F//4) were made by visual observation of the disppearance of a meniscus at the vapor-liquid interface within an optical cell. Twenty-three saturated densities between 410 K and the critical temperature were obtained in the density range 290 to 894 kg/m**3. The experimental uncertainties of temperature and density were estimated within plus or minus 15 mK and plus or minus 0. 5 %, respectively. On the basis of these results, the critical temperature ** TAU //c and the critical density ** rho //c for R 114 were determined to be 418. 78 K and 576 kg/m**3, respectively, in consideration of the disappearing meniscus level as well as the intensity of the critical opalescence.