The Preparation Of Three New Supported Catalysts And Study Of Their Application In Olefin Epoxidation Reactions

On an industrial scale, homogeneous catalysts are often expensive, involving troublesome work-up, thus reducing their scope. They are not easy to handle, difficult to separate, and have limited reuse potential often due to contamination with final products or formation of metal-complexes. As a result, people try to overcome the above disadvantages through the multiphase of homogeneous catalyst. The approach is to support the homogeneous catalyst to the organic or inorganic solid carrier, which making the catalyst catalyst can be the advantages of homogeneous catalyst and heterogeneous catalyst, and can be exempted from some drawbacks.In this paper, three kind of supported catalyst have been prepared, and been used to catalyze olefin with molecular oxygen as oxidant.Magnetic catalyst CoTCPc-MNPs have been prepared by physical mixing and used for 3-carene epoxidation with molecular oxygen. Under optimal conditions, the conversion of 3-carene reached 99%, whereas the selectivity of a-epoxycarane reached 71.4%.In addition, aluminum oxide-encapsulated metal (M=Co, Ni, and Fe) phthalocyanine catalysts (MPC/Al2O3) were investigated for the epoxidation of hydroxyl-terminated polybutadiene with molecular oxygen in the presence of a co-oxidant isobutyraldehyde. Metallophthalocyanines were encapsulated into support holes by "ship-in-a-bottle" synthesis, and the obtained catalysts, Al2O3-encapsulated metal phthalocyanines, were characterized by N2 adsorption, BET, ICP-AES, IR, UV-Visible, and XRD. The optimal conditions for the epoxidation of hydroxyl-terminated polybutadiene were as follows:reaction temperature, 40℃; molar fraction of catalysts to polybutadiene,2%; mass ratio of isobutyraldehyde to polybutadiene,2.5:1; oxygen flow,40 mL/min; reaction time,8h. Under optimal conditions, the double bond conversion of polybutadiene reached 67.05%. The reaction mechanism was found to be a free-radical reaction.Finally, another we prepared CoTCPc-MNPs magnetic catalyst using the "surface grafting" method by covalent coupling. We have successfully synthesized hydratropic aldehyd using this catalyst by epoxidation of α-methyl styrene. The optimal conditions for this reaction were as follows:reaction temperature,20℃; molar fraction of catalysts to polybutadiene,2.5%; mass ratio of isobutyraldehyde to polybutadiene,2:1; reaction time,6h. Under optimal conditions, the yield of hydratropic aldehyd ached 85.14%.