Studies On The Synthesis And Catalytic Oxidation Properties Of Polymer Supported 2,4-dihydroxyacetophenone Schiff-base Complexes

At the pressures of environmental and economic, the use of cheap and clean oxidants such as O₂ to selective catalytic oxidation of hydrocarbons under mild conditions were in line with the objective requirements of green chemistry and environmentally friendly, which were having great social and economic benefits. Therefore, it is efficient method to overcome the catalytic activity and carrying oxygen ability of the Schiff base complexes by immobilizing them onto the chloromethylated polystyrene. The papers includes the following five chaptersChapter 1: ReviewsIntroduced the Schiff base of the Research and application, make an overview of the application of in the catalytic reaction (catalytic oxidation, catalytic epoxidation and catalytic olefin polymerization); analytical chemistry; biological activity and functional materials.Chapter 2: Catalytic Oxidation Cumene by Supported Acetophenone Schiff base ComplexesChloromethylated polystyrene supported 2,4-dihydroxyacetophenone with 1,2-diaminobenzene Schiff base metal complexes PS-DHA-DAB-M (M=Cu, Co, Ni and Mn, respectively) were prepared and characterized by FT-IR, ICP, XPS. Their abilities to catalytic oxidation of cumene with oxygen were studied. Oxidation reactions occurred inα-C atoms. The main oxidation products were cumene hydroperoxide (CHP) and 2-phenyl-2-propanol (PP). In comparison with their catalytic activities, PS-DHA-DAB-Cu is a more effective catalyst for the oxidation of cumene and the conversion is 41%. The optimum condition of oxidation reaction is as followed: temperature: 383 K, cat.:sub. = 5 mg : 2 mL, 8 h. The selectivity for cumene CHP and PP are 76%,24% respectively. Chapter 3: Allylic Oxidation of Cyclohexene with Oxygen Catalyzed by Polymer Supported Dinuclear Schiff-base Complex Allylic oxidation of cyclohexene, using chloromethylated polystyrene supported 2,4-dihydroxyacetophenone with 1,3-Diamino-2-propanol dinuclear Schiff-base complexes (PS-DD-M, where M= Cu, Co, Ni and Mn) as catalyst and molecular oxygen as an oxidant, was studied. In the oxidation reaction, cyclohexene was oxidized to 1,2-cyclohexene oxide (EXO), 2-cyclohexene-1-ol (-OH), 2-cyclohexene-1-one (-C=O) and 2-cyclohexene-1-hydroperoxide (-OOH). It was found that the conversion of the oxidation reaction decreased in the order PS-DD-Cu > PS-DD-Mn > PS-DD-Co > PS-DD-Ni, but turnover number of the oxidation reaction decreased was PS-DD-Ni> PS-DD-Mn > PS-DD-Co > PS-DD-Cu. A maximum conversion for oxidation of cyclohexene (43%) was observed for PS-DD-Cu /O₂ system after 10 h of reaction at 343K when catalyst : substrate = 2 mg: 2 mL. The mechanism for oxidation of cyclohexene catalyzed by PS-DD-Cu/O₂ system is discussed.Chapter 4: Synthesis and Catalytic Properties of Chloromethylated Polystyrene Supported Tridentate Schiff-base ComplexesFour novel chloromethylated polystyrene supported tridentate Schiff-base metal complexes (PS-DA-M, M= Cu, Co, Ni and Mn, respectively) were prepared by chloromethylated polystyrene and tridentate Schiff-base ligands, which were synthesized by 2,4-dihydroxyacetophotone with 2-aminopyridine. The complexes were characterized by the methods of ICP, FT-IR, XPS and TG-DTA. The catalytic activity of the complexes in the oxidation of cyclohexene and cumene with molecular oxygen were determined. The results showed that PS-DA-Cu exhibited the best catalytic activity. The conversion of cyclohexene can be reached to 51.9%, and oxidation reaction was occurred in the allylic carbon atoms. The products are cyclohexene oxide, 2-cyclohexene-1-ol, 2-cyclohexene-1-one and 2-cyclohexene-1-hydroperoxide. The conversion of cumene can be reached to 62%, the main oxidation products were 2-phenyl-2-propanol (PP) and cumene hydroperoxide (CHP), The influences of reaction temperature, the amount of catalyst, the reaction time were also investigated.Chapter 5: Catalytic Oxidation Cumene by Supported new Dinuclear Symmetrical Schiff bases Transition Metal Complexes Chloromethylated polystyrene supported dinuclear Symmetrical Schiff base metal complexes PS-D-H2Lb-M (M=Cu, Co, Ni and Mn, respectively) were prepared in a simple way and characterized by FT-IR and TG-DTA. Their abilities to catalytic oxidation of cumene with oxygen in the absence of reductants or solvents were studied. In comparison with their catalytic activities, PS-D-H2Lb-Cu is a more effective catalyst for the oxidation of cumene and the conversion is 46.1%. The main oxidation products were 2-phenyl-2-propanol (PP) and cumene hydroperoxide (CHP). The influences of reaction temperature, the amount of catalyst, the amount of substrate, as well as the reaction time on the oxidation of cumene were also investigated.