Synthesis Of Hexafluoropropylene Oxide

Hexafluoropropylene Oxide (HFPO), one of the important organic fluorine chemical intermediates, has various applications in many fields. Existed synthesis processes include nucleophilic oxidation, direct oxidation with oxygen molecule, electrochemical oxidation, and carbonate-chlorine oxidation. HFPO is mainly produced by liquid-phase oxidation with molecular oxygen in industry. However, the price of HFPO is high due to high temperature and pressure in the process of reaction and its low selectivity. The nucleophilic oxidation by sodium hypochlorite requires low reaction conditions and has a high selectivity, in this paper; the synthesis process of the nucleophilic oxidation by sodium hypochlorite is improved and optimized in order to provide theoretical reference for industrial production.Two-phase liquid phase process was focused in this paper in which the sodium hypochlorite solution is selected as oxidant,1,1,2-three fluorine three ethyl chloride (F-113) is selected as the organic phase and three octyl dimethyl ammonium chloride (TOMAC) is selected as phase transfer catalyst. The reaction solvent was first selected and studied. The solubility of hexafluoropylene in solvents such as1,1,2-three fluorine three ethyl chloride (F-113), chloroform,1,2-dichloroethane, and acetonitrile significantly affect reaction selectivity and yield and F-113is show better performance.Then the effects of operation methods of raw materials was studied. GC was used for the qualitative and quantitative analysis of the gaseous product, and the structure of products in water phase was identified by nuclear magnetic resonance (NMR) analysis. The formation mechanism of products NaF, CF3COONa, CF3COONa and CF3CFHCOONa was then inferred based on NMR analysis.Compared with batch operation and continuous operation of HFP, the continuous operation of sodium hypochlorite solution give90%selectivity and the yield higher than80%. The generation mechanism of HFPO was inferred, the reaction intermediates and transition states was obtained by quantum chemical calculations which lay a theoretical foundation for obtaining higher yield of HFPO.Finally the effect of reaction temperature, amount of catalyst, aqueous phase to organic phase volume ratio, amount of NaOH and reaction time by controlling variable method is studied and the results show that when F-113is the organic phase, using sodium hypochlorite oxidizing agent, phases volume ratio1, three methyl octyl ammonium chloride2.5g, the temperature-12℃, and reaction time2h, the conversion is91.3%, the selectivity and yield are92.5%and84.5%respectively which is higher than the yield of liquid-phase oxidation with molecular oxygen.