Synthesis And Catalytic Properties Of Solid Acid Catalysts For Baeyer-Villiger Oxidation

The thesis consists of five chapters as follows:Chapter I: ReviewsThis chapter reviewed the recent progress of Baeyer-Villiger oxidation from five sections: The first section reviewed the history and the applications of Baeyer-Villiger reaction. The next section discussed the mechanism of the Baeyer-Villiger oxidation. The third section discribed the basic characteristic of this reaction. The forth section concluded varieties of oxidants used in the Baeyer-Villiger oxidation, such as m-CPBA, H₂O₂ and O2. The last section elaborated the catalytic Baeyer-Villiger oxidation from three aspects, including homogeneous catalysis, heterogeneous catalysis and enzyme-including systems, especially on heterogeneous catalysis, which contain zeolites, microporous and mesoporous materials, clays, silica, organic polymer supported catalysts, metal oxides and solid acid catalysts. Finally, a short conclusion was also proposed based on all of the reviews.Chapter II: Preparation and catalytic properties of silica supported sulfate in the Baeyer-Villiger oxidation of ketonesThree different kinds of silica supported sulfate solid acid catalysts were prepared by using the graft reaction between chlorosulfuric acid and hydroxide groups in the surface of silica. The prepared catalysts were characterized by FT-IR, TG-DTA, XRD, SEM and N2 adsorption-desorption methods. Their catalytic activities were first studied for the Baeyer-Villiger oxidations, and the optimum conditions were obtained from the investigation of the catalytic processes. It found that with 30% H₂O₂ as oxidant, the catalyst showed promising activities in the Baeyer-Villiger oxidation of ketones to the corresponding lactones under mild conditions. 2-Adamantanone and cyclohexanone were converted into the corresponding lactones almost quantitatively. Besides, catalytic esterification of varieties of carboxylic acid with ethanol were studied, results showed that the conversions and selectivities of most reactions were over 90%. The catalyst exhibited the advantages of simple preparation, mild reaction conditions, recyclability and multifunctions. Chapter III: Baeyer-Villiger oxidation of ketones catalyzed by PEG6000-OSO₃HPEG6000-OSO₃H was prepared and was characterized by FT-IR, TG and element analysis. Baeyer-Villiger oxidation of ketones catalyzed by PEG6000-OSO₃H with 30%H₂O₂ as oxidant was studied. The influences of the solvents, the reaction time, the temperature, the dosage of catalyst and the oxidant on the catalytic activity were well investigated. The optimizing conditions were concluded as: 0.1mmol ketones dissolved in 3mL of 1, 2-dichloroethane and oxidized by 10mg of PEG6000-OSO₃H with 0.3mmol of 30 %H₂O₂ at 70 oC for 24hs. Under the optimum condition, a series of cyclic ketones such as 2-adamantanone, cyclopentanone, cyclohexanone, 2-methylcyclohexanone, 4-methylcyclohexanone and 4-tert-butyl -cyclohexanone were well transformed into the corresponding lactones with the conversions of 89～100% and the selectivities of 89～99%, respectively. Chapter IV: Fabrication, characterization and catalytic studies of Sn-W mixed transition metal oxidesA series of Sn-W mixed transition metal oxides were synthesized through a simple coprecipitation and calcination approach. Due to the variation of Sn/W ratios and calcination temperatures, the obtained metal oxides had different catalytic properties. Among all of the oxides, the Sn/W-2-800 oxide showed the highest catalytic activities. The catalysts were characterized by FT-IR, XRD, SEM and N2 adsorpotion-desorpotion isotherms. The Sn/W-2-800 oxide acted as an effective heterogeneous catalyst for the Baeyer-Villiger oxidation of ketones and the Friedel-Crafts alkylation of anisole with benzyl alcohol. Many of ketones, as well as benzyl alcohol, were transformed into the corresponding products with high conversion and selectivity. Both ortho- and para-benzylanisole were formed in the reaction, and no meta-product was detected. This reaction condition is mild and the catalysts can be reused for at least five cycles without significant loss of activity. Chapter V: Summary and OutlookThe main conclusion and the research significance of this paper were summarized, the relevant application prospects of the synthesized solid acid catalyst were described, and it also pointed out its deficiency.