Design of a continuous gas-phase process for the production of hexafluoropropene oxide

•Small diameter reactor tube fabricated from copper used for oxidation of HFP.•Gas phase continuous process scaled up to 500 tpa using parallel reactor tubes.•Proposed gas phase oxidation process is at least 30% cheaper to commission and operate.

The partial oxidation of hexafluoropropene (HFP) yields 2,2,3-trifluoro-3-trifluoromethyl oxirane (commonly known as hexafluoropropene oxide, HFPO), a highly reactive and versatile fluorochemical intermediate that is used in the manufacture of various high-performance organofluorine products. Most industrial methods of HFPO preparation involve the high-pressure liquid-phase oxidation of HFP in the presence of chemical oxidizers and solvents. Processes that employ molecular oxygen as the oxidizing agent generally have a lower environmental impact. In this study, the design and analysis of a 500 tpa continuous gas-phase process for the epoxidation of HFP with molecular oxygen was carried out. A modular coil-type reactor fabricated from drawn copper tubing is proposed to attain residence times up to 120 s which are required for acceptable levels of HFP conversion (70%) and HFPO yield (40%). The HFPO product is separated from the residual HFP through a novel sequence of CO2 gas stripping and conventional distillation steps. A final product having a purity of 99.8 mol% is obtained. The recovered HFP, which has a purity of 99.2 mol%, is subsequently recycled. The process unit operates at a HFP recycle ratio of 0.39.

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