Measurements of the Vapor-Liquid Coexistence Curve for the R 13B1 + R 114 System in the Critical Region

Measurements of the vapor-liquid coexistence curve in the critical region for the refrigerant mixture of bromotrHIuoromethane (CBrF₃, R 13B1) and 1,2-dlchloro-1,1,2,2-tetrafluoroethane (CCIF₂CCIF₂, R 114) were made by visual observation of the disappearance of the meniscus at the vapor-liquid Interface within an optical cell. Eighteen saturated-vapor densities and 21 saturated-liquid densities for four different compositions of 25, 50, 70, and 80 wt % R 13B1 between 345 and 406 K were obtained in the range of densities 356-1166 kg/m3. The experimental error of temperature, density, and mass fraction was estimated within ±15 mK, ±0.5%, and ±0.05%, respectively. On the basis of these measurements, the critical curve of the R 13B1 + R 114 system is determined and compared with several predictive methods. In addition, new correlation so as to represent the composition dependence of the critical parameters for the R 13B1 + R 114 system is proposed.