Studies On Synthesis And Catalytic Properties Of Tin-containing Compounds For Baeyer-Villiger Oxidation Of Ketones

The thesis consists of four parts as followings:Partâ… ReviewsIt reviews the recent progress of Baeyer-Villiger oxidation from the four sections:The first section reviews the history, the oxidation methods and the applications of Baeyer-Villiger reaction.The second section reviews the mechanism of the Baeyer-Villiger oxidation. The varieties of methodologies for the oxidation were also discussed.The third section reviews the methods for the achievement of Baeyer-Villiger oxidation according to the recent literatures. This includes bio-methods and chem-methods. In the bio-methods, much of the Baeyer-Villiger monoxygenases (BVMOs) including CHMO, CPMO, CDMO, SMO, and HAPMO were mentioned for the enzyme catalytic Baeyer-Villiger oxidations. In the chem-methods, it reviews the advancement of Baeyer-Villiger oxidation from the two subsections: (i) the direct oxidation reactions, that is, much of the ketones were directly oxidized with some peroxides through chem-methods in the absence of catalysts. (ii) The chem-catalytic oxidation of ketones in the presence of oxidants. In this subsection, much of metal-containing catalysts such as tin-containing catalysts, the rhenium oxide (MTO) catalysts, the selenium compounds, the heteroacides catalysts and the metal complex catalysts for the Baeyer-Villiger oxidations were described in detail.Partâ…¡Baeyer-Villiger oxidation catalyzed by inorganic Sn catalystsSn-containing inorganic catalysts were prepared and well characterized. Their catalytic properties for the Baeyer-Villiger oxidation were further investigated among the four chapters below:Chapter one: Baeyer-Villiger oxidation of ketones catalyzed by silica supported Sn catalysts Four kinds of silica supported Sn catalysts with different percent of Sn-loading were prepared. Their catalytic activities for the catalytic Baeyer-Villiger oxidation of ketones were well investigated through the model oxidation reaction of adamantanone. It was found that all of the catalysts showed promising catalytic activities for the oxidation of adamantanone. Within 24 hours, adamantanone can be completely oxidized to the corresponding lactones with the selectivity of 100%. 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 Sn catalysts, many ketones can be oxidized with 30% H₂O₂ in 1,2-dichloroethane.Chapter two: Baeyer-Villiger oxidation of ketones catalyzed by the hydrolyzed product of SnCl₂·2H₂O in waterSnCl₂·2H₂O was hydrolyzed in distilled water and the product showed catalytic activities for the Baeyer-Villiger oxidation of ketones by 30% H₂O₂. The optimizing reaction condition was concluded through the study of the Baeyer-Villiger oxidation of adamantanone. It was found that with the catalyst, many ketones can be oxidized in the oxidation system with high substrate conversion and high selectivity to the lactones.Chapter three: Baeyer-Villiger oxidation of ketones catalyzed by SnCl₂·2H₂OSnCl₂·2H₂O is directly used as catalyst for the oxidation without further treatment. The results show that adamantanone can be completely oxidized by 30% H₂O₂. Many other ketones can also be oxidized by 30% H₂O₂ in 1,2-dichloroethane solution in the presence of SnCl₂·2H₂O under the optimizing condition obtained in the oxidation of adamantanone.Chapter four: Baeyer-Villiger oxidation of ketones catalyzed by the alcoholated product of SnCl₂·2H₂O in absolute ethanolSnCl₂·2H₂O was alcoholated in absolute ethanol to afford the catalyst for the Baeyer-Villiger oxidation of ketones. The catalytic activity of the obtained catalyst was well investigated and the optimizing condition was concluded through the study of the Baeyer-Villiger oxidation of adamantanone by 30% H₂O₂ in ethanol solution. It was found that with the catalyst, many ketones can also be oxidized in the oxidation system. Partâ…¢Baeyer-Villiger oxidation catalyzed by organic Sn catalystsA series of Sn-containing organic catalysts were prepared and well characterized. Their catalytic properties for the Baeyer-Villiger oxidation were also investigated through the four chapters as below:Chapter one: synthesis and catalytic properties of natural konjac gun supported Sn complexes for the Baeyer-Villiger oxidation of ketones by 30% H₂O₂The natural polymer konjac gun supported Sn was synthesized, the catalytic properties for the Baeyer-Villiger oxidation of ketones was investigated. It was showed that many ketones including cyclic and acyclic ketones can be oxidized with the catalysis of the supported catalysts by 30% H₂O₂. All of the oxidation reactions bear the properties of high conversion and high selectivity.Chapter two: synthesis and catalytic properties of chitosan supported Sn complexes for the Baeyer-Villiger oxidation of ketones by 30% H₂O₂Chitosan was prepared through the treatment of natural chitin. The chitosan supported Sn catalysts were synthesized through the reactions of chitosan with SnCl₂·H₂O or BuSnCl₃. The catalytic properties of the two supported catalysts were investigated through the oxidation of adamantanone in ethanol by 30% H₂O₂. The result is not exciting. It was found that the two catalysts only showed catalytic activity for the oxidation of adamantanone.Chapter three: synthesis and catalytic properties of melamine Sn complex for the Baeyer-Villiger oxidation of ketones by 30% H₂O₂The complex of melamine with SnCl₂·2H₂O was prepared. The catalytic activity of the complex for the Baeyer-Villiger oxidation was further investigated. The results showed that adamantanone, cyclohexanone derivatives, cyclopentanone and some aliphatic chain ketones can be oxidized to the corresponding lactones with the selectivity of 100% in the presence of the complex.Chapter four: synthesis and catalytic properties of 2,4-diamino-6-hydroxy pyrimidine Sn complexes for the Baeyer-Villiger oxidation of ketones by 30% H₂O₂Two Sn-containing complexes derived from 2,4-diamino-6-hydroxy pyrimidine were synthesized through the reaction of 2,4-diamino-6-hydroxy pyrimidine with Me₂SnCl₂ or BuSnCl₃. Their catalytic properties for the Baeyer-Villiger oxidation of ketones were investigated. It was found that the complexes performed promising activities for the catalytic oxidation of many ketones by 30% H₂O₂. Complex formed from the reaction of 2,4-diamino-6-hydroxy pynmidine with BuSnCl₃ bears higher catalytic activity than that of the complex formed from the reaction of 2,4-diamino-6-hydroxy pyrimidine with Me₂SnCl₂ under identical condition.Partâ…£Proposal mechanism of the catalytic Baeyer-Villiger oxidation of ketones catalyzed by the Sn-containing catalystsBased on the oxidation results of ketones, the influencing factors of the reactions as well as the relative literatures, a proposal mechanism pattern of Baeyer-Villiger oxidation of ketones catalyzed by all of the synthesized Sn-containing catalysts was afforded. A short explanation of the proposal mechanism was also supplied according to the schematic pattern.