Selectivity and Phase Equilibrium Data for Extractive Distillation of Hexafluoropropylene from Its Oxide

Separation of 1,1,2,3,3,3-hexafluoro-1-propene from 2,2,3-trifluoro-3-(trifluoromethyl)oxirane using conventional distillation is challenging due to their close-boiling nature and unfavorable relative volatility. This study presents phase equilibrium data at 303.2 K and low concentrations using the isothermal synthetic method for the binary systems of 1,1,2,3,3,3-hexafluoro-1-propene or 2,2,3-trifluoro-3-(trifluoromethyl)oxirane with the solvents dibutyl ether, dichloromethane, and chloroform to assess their suitability for extractive distillation. Additionally, moderate pressure phase equilibrium data were measured using the static analytic method for the binary systems of 1,1,2,3,3,3-hexafluoro-1-propene or 2,2,3-trifluoro-3-(trifluoromethyl) oxirane with dibutyl ether at temperatures of 303.2, 323.2, and 343.2 K. The Peng–Robinson Equation of State with the Wong-Sandler mixing rule and the non-random-two-liquid model was used to model the data. Although dibutyl ether has a moderately lower selectivity than dichloromethane, it possesses the highest capacity, suggesting that dibutyl ether could be a potential solvent for the extractive distillation of 1,1,2,3,3,3-hexafluoro-1-propene from 2,2,3-trifluoro-3-(trifluoromethyl)oxirane.