Synthesis of Hexafluoropropylene Oxide from Hexafluoropropylene and Hypochlorite Using Hydrofluoroether Solvent

Hexafluoropropylene oxide (HFPO) is a versatile fluorochemical widely used in the synthesis of various fluorinated compounds and fluorinated polymers. In this paper, we report on the successful synthesis of HFPO via the epoxidation of hexafluoropropylene (HFP) with NaOCl in a two-phase solvent system. Among the organic phase solvents tested, hydrofluoroethers such as C₄F₉OCH₃, C₄F₉OC₂H_5, and C₇F₁₅OC₂H₅ showed high HFPO yields, indicating their potential to replace conventional CFCl₂CF₂Cl (CFC-113), which is ozone depleting and global warming chemical. When the reaction was carried out for 20 min at room temperature, the C₄F₉OCH₃—water two-phase system produced HFPO with over 40% yield and over 70% selectivity. To optimize the reaction conditions, various reaction parameters were investigated, including the effects of NaOH and phase transition catalysts. Analysis of the by-products using ¹⁹F and ¹³C NMR and X-ray diffraction (XRD) showed that HFP/HFPO decomposes during oxidation to F¯, CO₂, oxalate, trifluoroacetate, etc. Density functional theory (DFT) calculations elucidated the reaction pathway of this epoxidation: with a lower E-barrier of 12.8 kcal/mol, the nucleophilic attack of OCl¯ on the β-carbon of HFP is preferable to the α-carbon pathway.