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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