Heterogeneous catalyst for catalyzing asymmetric Aldol reaction and preparation method thereof

Abstract

The invention discloses a heterogeneous catalyst for catalyzing an asymmetric Aldol reaction, and comprises immobilization of a dipyridine proline derivative onto a metal modified bimodal mesoporous silicon oxide nano-material carrier. The invention discloses a preparation method of the heterogeneous catalyst. The preparation method comprises the following steps: preparing a bimodal mesoporous silicon oxide nano-material, preparing the metal modified bimodal mesoporous silicon oxide nano-material carrier, and immobilizing the dipyridine proline derivative. The immobilization of the dipyridine proline derivative and metal of the metal modified bimodal mesoporous silicon oxide nano-material carrier is carried out by coordination, so that the preparation technology is simple, cost is low, the structure of the catalyst is controllable, and the reaction condition is mild; the catalyst can be recycled and recovered, and is easy to separate.

Description

technical field [0001] The invention relates to the field of chemical catalysts, in particular to a heterogeneous catalyst for catalyzing asymmetric Aldol reaction and a preparation method thereof. Background technique [0002] In recent years, the direct asymmetric Aldol reaction (aldol condensation reaction) catalyzed by proline and its derivatives has the advantages of atom economy, high enantioselectivity, mild reaction conditions, simple operation, and less pollution. It is an important means of bonding and is an indispensable reaction in asymmetric organic synthesis and drug synthesis. However, there are still shortcomings such as a large amount of catalyst used, difficult to recycle and unable to be reused. [0003] At present, many workers are studying the reaction of proline and its derivatives using acid-base groups, loading them on mesoporous materials, and then performing catalytic reactions. Such as Doyaguez et al. (J.Org.Chem., 2007,72:9353-9356) have synthes...

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Problems solved by technology

Such as Doyaguez et al. (J.Org.Chem., 2007,72:9353-9356) have synthesized a kind of heterogeneous catalyst MCM41-Pro (C) by convergent method, but the synthetic operation step of convergent method is more loaded down with trivial details, and required reagent uses large

Dhar et al. (Proc.Inndian.Acad.Sci.Chem.Sci.2003,115,365-372) synthesized the MCM-41 grafted L-proline catalyst by covalent linkage method for catalyzing the reaction between aromatic aldehyde and acetone However, due to the difficulty of mass transfer in heterogeneous reactions, the catalytic activity and stereoselectivity of the catalyst are lower than those of homogeneous catalysts.

Patent CN103447085A uses sulfhydryl-modified SBA-15 as a carrier, and hydroxyproline derivatives as active centers to obtain heterogeneous acid-base bifunctional catalysts through covalent reactions, and is applied to Aldol-Michael asymmetric series reactions, but the method The experimental conditions are relatively harsh and the operation is complicated

Therefore, the heterogeneous catalyst experimental condition that above-mentioned method forms is harsh, and catalyst is unstable

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