Study On The Synthesis Of Hexafluoropropylene Oxide From Hexafluoropropylene

Hexafluoropropylene oxide has a wide range of application values because it can be used to manufacture various high-performance organic fluorine products.It is usually produced by epoxidation of hexafluoropropylene.The existing processes are mainly divided into direct oxidation by oxygen,catalytic oxidation by oxygen,oxidation by liquid-phase oxidant,and other methods.First,the direct oxidation process by oxygen was studied.After the solvent was chosen,the ratio of substrate/solvent,the initial partial pressure of oxygen,the pureness of oxygen,and the temperature were optimized based on the induction period,reaction time,conversion and selectivity.After comprehensive consideration,under the conditions of 50 g hexafluoropropene,375 g hexafluoropropane,0.2 MPa oxygen partial pressure,130℃ rotation speed of 350 rpm,the reaction was carried out for 49 minutes,as a result,a conversion of 26.1%and a selectivity of 67.4%were obtained.Secondly,the process of catalytic oxidation by tert-Butyl hydroperoxide was studied.After the solvent and catalyst were chosen,the ratio of solvent/oxidant,catalyst dosage,temperature,and reaction time were optimized.Under the conditions of 2.2 g hexafluoropropene,20 g.perfluorooctane,10 g 40%tert-butyl hydroperoxide decane solution,0.3 g MoO2(acac)2,100℃,after 4 h of reaction,a conversion of 86.5%and a selectivity of 43.3%were obtained.Then the process of oxidation by hydrogen peroxide at low temperature was studied.The ratio of solvent/oxidant,the dosage of phase transfer catalyst,the amount of NaOH,the temperature,and the reaction time were optimized.Under the conditions of 2.2 g hexafluoropropene,20 g.perfluorooctane,15 g 30%hydrogen peroxide aqueous solution,0.3 g TOMAC,1.0 g NaOH,-5℃,after 5 h of reaction,a conversion of 42.3%,a selectivity of 90.0%was obtained.Inspired by the advantages of low-temperature,the oxidation process by NaClOwas studied.After the solvent and phase transfer catalyst were chosen,the ratio of solvent/oxidant,pH of the reaction solution,concentration of sodium hypochlorite,phase transfer catalyst dosage,temperature and the reaction time were optimized.Under the conditions of 2.2 g hexafluoropropylene,20 g perfluorooctane,15 g 12.5%NaClOaqueous solution,0.3 g CTAB,0℃,after 5 h of reaction,a conversion of 40.5%,a selectivity of 95.1%,and the yield is 38.5%was obtained.Finally,the continuous oxidation process in the microchannel reactor was studied.The organic phase composed by perfluorooctane containing 17.7 wt%of hexafluoropropylene was prepared,the aqueous phase composed by 12.5%NaClOaqueous solution containing 0.7 wt%of CTAB was prepared.When the organic phase flow rate was 1 mL/min,the aqueous phase flow rate was 3 mL/min,10 microreactors are used for the reaction at 0℃ a conversion of 70.9%and a selectivity of 94.9%was obtained.The highest yield of 67.3%was achieved.