Heteropoly Acid And SBA-15 Supported Heteropoly Acid Catalyzed Baeyer-Villiger Oxidation Of Cyclic Ketones

The thesis consists of three chapters as follows:Chapter one: ReviewsThe chapter reviewed the recent progress of Baeyer-Villiger oxidation from the four subsections including: (1) The history of the Baeyer-Villiger oxidation; (2) The mechanism of the oxidation; (3) The characteristics of the reaction and (4) The progress of Baeyer-Villiger oxidation. Meanwhile progress of both oxidants and catalysts were introduced separately. As far as catalysts applications are concerned, we mainly introduced the applications of heterogeneous catalyst in Baeyer-villiger oxidation reaction. The organic polymer supporters as well as the inorganic supporters (such as zeolite, silica, clay and et al.) and other heterogeneous materials (metal oxide, solid acid et al.) supported catalysts were well introduced. Chapter two: Baeyer-Villiger oxidation of cyclic ketones catalyzed by heteropoly acidsThree simple heteropoly acids (HPAs), including silicotungstic acid, tungstophosphoric acid and molybdophosphoric acid, were proved to be efficient and reusable catalysts for Baeyer-Villiger oxidation of ketones in the presence of 30%H2O2 under mild conditions. The effect of the solvent, the reaction time, the reaction temperature, and the amount of catalyst used were investigated in details. It was found that silicotungstic acid showed the highest catalytic activity among the three selected HPAs, and many cyclic ketones were efficiently converted to the corresponding lactones with up to 90% conversions (21%-86% yields) and high selectivities under the optimum reaction conditions. The catalyst could be recycled and be reused at least three times without obvious loss of activity and selectivity. Chapter three: Baeyer-Villiger oxidation of cyclic ketones catalyzed by SBA-15 supported silicotungstic acidFour kinds of SBA-15 supported silicotungstic acid catalysts with different percent of silicotungstic acid-loading were prepared. Their catalytic activities for the catalytic Baeyer-Villiger oxidation of ketones were well investigated through the oxidation of cyclohexanone as a model reaction. It was found that all of the catalysts showed promising catalytic activities for the oxidation. Within 8 hours, cyclohexanone can be effectively oxidized to the corresponding lactones with the selectivity of 99%. Their catalytic activities for the Baeyer-Villiger oxidation of other ketones were also well investigated. All of the results show that with the catalysis of the supported silicotungstic acid catalysts, many ketones can be oxidized with 30% H₂O₂ in 1, 2-dichloroethane. The catalytic system bears the obvious advantages such as simply preparation and the high activity of the catalyst.