Synthesis, Characterization And Catalytic Properties Of Mesoporous Materials Supported Heteropoly Acids For Baeyer-Villiger Oxidation Of Cyclic Ketones

The thesis consists of three chapters as follows:Chapter one: ReviewsThis chapter mainly reviewed the following four subsections including （1） TheBaeyer-Villiger oxidation. The commomly considered mechanism of the Baeyer-Villiger oxidation were well reviewed, the the progress of the oxidants and thecatalysts in the oxidation were also discussed.（2） The heteropoly acid. The history ofthe heteropoly acid were introduced, the structure and property of the heteropoly acidand the supported heteropolyacid;（3） The mesoporous molecular sieve. The evolutionand classification of the mesoporous materials and their synthesis methods, theirformation mechanisms, as well as the advances of mesoporous materials supportedheteropoly acids and their application were reviewed in this part;（4） Themontmorillonite （MMT）. The structure and property of montmorillonite and the basicknowledge of pillared montmorillonite were introduced separately.Chapter two: Synthesis, characterization and catalytic properties of the molecularsieves incorporated with H4SiW12O40for Baeyer-Villiger oxidation of cyclic ketones.In this chapter, we synthesized the mesoporous molecular sieves （SBA-15,MCM-41, MCM-48） incorporated with HSiW （denoted as HSiW/SBA-15,HSiW/MCM-41, HSiW/MCM-48） via a direct method. All of the samples werecharacterized by powder X-ray diffraction （XRD）, scaning electron microscopy（SEM）, transmmission electron microscopy （TEM）, Fourier transform infraredspectroscopy （FT-IR） determing techniques, followed by the catalytic property tests.The characterization results approves that Keggin unit are retained and encapsulatedinto the pore of the mesoporous silica, and an ordered channels with homogeneouspore diameters is obtained in the materials. The results also show that the HSiW washighly dispersed in the samples. In the catalytic investigation, the effect of oxidationconditions such as solvent, reaction time, the amount of catalyst, and reactiontemperature are discussed. It was found that all the three catalysts showed highcatalytic activity in the Baryer-Villiger oxidation of ketones, and many cyclic ketoneswere efficiently converted to the corresponding lactones and high selectivities under the optimum reaction conditions. Due to the successful supporting of the cativespecies, it is proved that all the samples can be reused in the oxidation.Chapter three: Synthesis, characterization and catalytic properties of the mesoporoussilica pillared montmorillonite incorporated with H₄SiW₁₂O₄₀for Baeyer-Villigeroxidation of cyclic ketones.The ordered mesoporous silica pillared montmorillonite （SPM） with differentloadings of silicotungstic acid （denoted as x%HSiW-SPM） were successfully obtained.The HSiW was encapsulated into the gallery silica framework structure by sol-gelmethod involving the introduction of the HPW into clay interlayer template in anacidic suspension. These materials were characterized by powder X-ray diffraction（XRD）, N2-adsorption-desorption analysis （BET）, thermogravimetric analysis （TG）,and scaning electron microscopy （SEM）. Such mesoporous materials weresuccessfully used as catalysts in the Baeyer-Villiger oxidation of cyclic ketones to thecorresponding lactones, and96%of conversion as well as more than99%lactoneselectivity were obtained in thw oxidation of cyclohexanone. At the same time, manyother cyclic ketones were efficiently converted to the corresponding lactones with85%-100%conversions and high selectivities under the optimum reaction conditions.The catalyst could be recycled and be reused at least thirteen times without obviousloss of activity and selectivity in the oxidation of adamantanone.