Selective absorption of ionic liquids in separating R-1243zf or R-161 from refrigerant blends

Abstract

In order to recover and reuse pure refrigerants from the mixtures used in waste refrigeration facility, it is necessary to find a good way for separation. Due to the extremely low vapor pressure and good selectivity, ionic liquids (ILs) are regarded as promising entrainers for the extractive separation process of azeotropic or near-azeotropic mixtures. Phase behavior of refrigerant with ILs is the basic property in the design of selective absorption-separation process. In this work, the solubility of 3,3,3-trifluoropropene (R-1243zf) and ethyl fluoride (R-161) with trihexyltetradecylphosphonium chloride ([P_6,6,6,14][Cl]) were measured based on the isochoric saturation method. The experimental temperature range was from 283.15 K to 343.15 K. Five activity coefficient models, including Margules, van Laar, Scatchard-Hamer, Wilson and non-random two-liquid (NRTL) model, were used to correlate the experimental data, and the results were discussed. In addition, based on the literature data, the separation capacities of different ILs for refrigerant blends composed of R-1243zf or R-161 were investigated.