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In the field of catalysis, non functionalized organic synthesis epoxidation of olefins has been a concern of chemists hotspot. So far, a lot of metal complexes has been applied to the epoxidation of olefins. Among them, the organic hydrogen peroxide as an oxygen source homogeneous catalytic epoxidation of unfunctionalized olefins reaction, Schiff base-type molybdenum complexes as catalysts is considered to be the most promising metal complexes. Although such complexes have high activity, selectivity and relatively mild reaction conditions, etc., but because it is homogeneous reaction, so the presence of a catalyst is easy to break down, it is difficult to recycle, easy to form multimers and inactivation and many are common disadvantage of catalysts. To solve this academic problem, scholars from various countries will have homogeneous catalysts supported on a polymer carrier or inorganic carrier to obtain a convenient recyclable heterogeneous catalyst, to achieve progress through the heterogeneous reaction - further research purposes. Thus, in studying non-functionalized olefin epoxidation at the same time, for a variety of carriers and homogeneous catalysts and methods of immobilization has entered a new stage. In our group research papers based on the results of the organic polymer - inorganic hybrid new carrier poly (styrene - styrene phosphonic acid) - further derivatized zirconium hydrogen phosphate, was prepared by solid-phase synthesis of a series of new bidentate, tridentate Schiff base type immobilized molybdenum metal complexes as heterogeneous catalysts unfunctionalized olefins epoxidation. The reaction system as t-butyl hydroperoxide oxygen source, 1,2 - dichloroethane as the solvent, the catalyst for some substrates show very good catalytic effect. The results show that such catalyst can be reused up to ten times more still has a very good catalytic activity. Interestingly, in order to α-methyl styrene and indene as the substrate, the blank test to obtain the corresponding epoxide can ee of greater than 99%. When adding a heterogeneous catalyst, the substrate conversion and epoxide selectivity greatly improved, the most important is the target product PP value is still 99%. It is worth mentioning that this process does not use any expensive chiral ligands or cocatalyst, such a catalyst is effective to accelerate the catalytic reaction process. Through its ligand design, more extensive screening reaction substrate, the substrate should be able to further improve the conversion rate and the corresponding epoxide selectivity. This class achiral heterogeneous catalyst will increase larger epoxidation of olefins enantioselective far-reaching significance for the practical application of industrialization provide an important reference.
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