Cyclohexene Epoxidation Usin Hydrogen Peroxide Over Ouaternarv Ammonium Heteropolytungstoborate Catalyst

Cyclohexene epoxidation is the probe reaction of olefins epoxidation.Cyclohexene oxide, the product of cyclohexene epoxidation, due to its lively epoxy group structure, it can react with amino, phenol, alcohol and carboxylic acid to synthesis a serie of high value-added compounds. Therefore, the development of a high efficiency catalyst for cyclohexene oxide with cyclohexene is of great academic value and potential prospect of industrial application.There are five chapters in this theme. First, gives a review about the progress of catalysts for cyclohexene oxidation in the last decade, and processes the research ideas. Then, the experimental materials, experimental equipments, and the method of catalyst characterization and catalyst test are put forward.Chapter3is the preparation methods of phase-transfer catalyst quaternary ammonium heteropolytungstobotare and the catalytic performance in cyclohexene oxidation using hydrogen peroxide as an oxidant. A best scheme to catalyst preparation was obtained by the exploration of various factors. An8.25g sample of sodium tungstate (Na2WO4·2HoO) was dissolved in50mL deionized water. A16.34g solution of30wt.%diluted sulphuric acid was added while stirring and the pale yellow precipitate appeared. Add30wt.%hydrogenperoxide drop by drop with vigorous stirring until the precipitate disappeared. Add0.52g (W/B=3) boricacid, and reacted for30min under70℃. Add2.76g cetyltrimethylammonium chloride (CTMA), and reacted for another60min under70℃with much more vigorous stirring. Cooled down to room temperature and filtrated with a funnel. Wash the solid with a large number of deionized water and dry it for11h under40℃. The light yellow solid catalyst was marked as Cat23.It behaved high catalytic activity and exhibited a good selectivity to cyclohexene oxide without any solvents or environmental contamination. Two optimum reaction conditions were investigated, one is high temperature, short time:reaction temperature60℃, molar ratio of H2O2to cyclohexene1:1, cyclohexene dosage4.10g, catalyst dosage0.5g and reaction tine3h, and conversion of cyclohexene52.3%and selectivity to cyclohexene oxide67.4%were obtained under the above reaction conditions. Another optimum reaction conditions with lower temperature and longer time were investigated, and the conversion of cyclohexene51.2%and selectivity to cyclohexene oxide69.2%were obtained with the conditions of reaction temperature35℃, molar ratio of H2O2to cyclohexene1:1, cyclohexene dosage4.10g, catalyst dosage0.5g and reaction time24h.Chapter4was the result of characterization. Chapter5summarizes the main contents of the dissertation, and several research suggestions about cyclohexene oxidation on phase-transfer catalyst quaternary ammonium heteropolytungstobotare.