(373s) Separation of HFC-32, HFC-125, HFC-134a, HCFC-22, and HFO-1234yf Using Copolymers of Perfluoro(butenyl vinyl ether) and Perfluoro(2,2-dimethyl-1,3-dioxole)

Recent legislation has called for the phase-out of greenhouse gases that trap heat in our atmosphere. One specific class of compounds targeted for phaseouts are hydrofluorocarbons (HFCs). HFCs are fluorinated gases commonly used in refrigeration and cooling systems. With an increased legislative focus on reducing the use of high GWP refrigerants, methods for separating and repurposing low GWP refrigerants from high GWP mixtures are imperative. Many refrigerant mixtures are azeotropic, making their separation difficult and energy intensive. Membranes provide the opportunity to separate refrigerant mixtures and achieve a high selectivity while being less energy intensive in comparison to other separation technologies. In this work, amorphous perfluorinated copolymers of perfluoro(butenyl vinyl ether) (PBVE) and perfluoro(2,2-dimethyl-1,3-dioxole) (PDD) were used to investigate the permeability, solubility, and diffusivity of 5 different refrigerants: difluoromethane (HFC-32), pentafluoroethane (HFC-125, CHF₂CF₃), 1,1,1,2-tetrafluoroethane (HFC-134a, CH₂FCF₃), chlorodifluoromethane (HCFC-22, CHClF₂), and 2,3,3,3-tetrafluoropropene (HFO-1234yf, CH₂=CFCF₃). Results can be used to inform the separation of a variety of commonly used refrigerant mixtures, such as R-410A (50 wt% HFC-32 and 50 wt% HFC-125) and R-407C (23 wt% HFC-32, 25 wt% HFC-125, and 52 wt% HFC-134a).