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Load type chiral catalyst and preparation method thereof

A chiral catalyst, supported technology, applied in organic chemistry methods, chemical instruments and methods, physical/chemical process catalysts, etc., can solve the problems of low catalytic activity, poor stereoselectivity, difficult to control, etc., to achieve high catalytic activity, The effect of improving activity and improving dispersibility

Inactive Publication Date: 2013-02-06
HENAN NORMAL UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The more commonly used methods for supporting chiral catalysts are: (1) using insoluble cross-linked polymers or inorganic materials as carriers; (2) using soluble linear polymers or dendrimers as carriers, but these two methods have their own advantages and disadvantages. Advantages and disadvantages, although the catalyst prepared by method (1) is easy to separate, easy to operate, and can be reused many times, but the structure of the catalytic active site is complex and difficult to control. Compared with the homogeneous catalyst, the catalytic activity is low and the stereoselectivity is poor; The catalyst prepared by the method (2) maintains the characteristics of high catalytic activity and high stereoselectivity of the homogeneous catalyst, and the catalyst can be separated from the reaction system by a certain method, but the separation method is relatively more difficult than the method (1). still more complicated
Therefore, it is still difficult for the currently developed supported chiral catalysts to fully combine the advantages of high activity and high selectivity of homogeneous catalysts with the advantages of easy separation and reusability of heterogeneous catalysts.

Method used

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  • Load type chiral catalyst and preparation method thereof
  • Load type chiral catalyst and preparation method thereof
  • Load type chiral catalyst and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] Preparation of nano-silica:

[0016] Add 20 mL of deionized water and 23 mL of ethanol to a 250 mL two-neck round bottom flask, dilute 10 mL of ammonia water with a mass concentration of 25% to 50 mL with deionized water, add it to the flask, and add 77 mL of ethanol and 7.2 mL of a mixture of tetraethyl orthosilicate (TEOS) (ultrasonic for 30 minutes with an ultrasonic instrument), was added dropwise, stirred at room temperature for 3 hours, centrifuged, washed with ethanol for 3 times, and dried in a vacuum oven to obtain Nano silicon dioxide, its diameter is about 250 nm, its scanning electron microscope picture is shown in Figure 4 ;

[0017] Preparation of nano silica with surface grafted chain transfer agent:

[0018] Add 8 g of spherical nano-silica and 250 mL of anhydrous toluene to the reaction flask, install a water separator and reflux until the anhydrous phase of the distillate is separated, remove the water separator after cooling to room temperature, an...

Embodiment 2

[0028] Preparation of nano-silica:

[0029] Add 20 mL of deionized water and 23 mL of ethanol to a 250 mL two-necked round-bottom flask, dilute 10 mL of ammonia water with a mass concentration of 25% to 50 mL with deionized water, add it to the flask, and add 77 mL of ethanol and 9 mL of a mixture of tetraethyl orthosilicate (TEOS) (sonication for 30 minutes with an ultrasonic instrument), the dropwise addition was completed, the reaction was stirred at room temperature for 3 hours, centrifuged, washed with ethanol for 3 times, and dried in a vacuum oven to obtain nano silica;

[0030] Preparation of nano silica with surface grafted chain transfer agent:

[0031] Add 8 g of spherical nano-silica and 250 mL of anhydrous toluene to the reaction flask, install a water separator and reflux until the anhydrous phase of the distillate is separated, remove the water separator after cooling to room temperature, and add 8 g of chain transfer agent S -Methoxycarbonylbenzyl S′-trimetho...

Embodiment 3

[0039] Add the hair-like nano-silica II prepared in Example 1, 0.1 mmol p-nitrobenzaldehyde, 1 mL acetone and 2 mL DMF in the test tube, react at room temperature for 48 hours, and form a thin layer Chromatography followed the reaction to the end point, after the reaction was completed, centrifuged, the supernatant was extracted three times with ethyl acetate (3 × 10mL), the organic phases were combined, concentrated, and separated by column chromatography to obtain a pure addition product (petroleum ether: acetic acid Ethyl ester=4:1), weighing and calculating yield, hydrogen nuclear magnetic resonance spectrum confirms the target product, separates chiral substance by AD-H chiral column, high performance liquid chromatography (HPLC) records yield to be 82%, e.e. The value is 90%.

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Abstract

The invention discloses a load type chiral catalyst and a preparation method thereof. The load type chiral catalyst is characterized in that the load type chiral catalyst is proline-loaded hair-shaped silica nano particle obtained by forming a functional group on the surface of nano silica in a finishing manner, triggering chiral N-p-vinyltoluene sulfonyl-Boc-L-proline amide to polymerize by an reversible-breakage-chain transfer polymerization method, grafting a chiral polymer chain on the surface of the nano silica and further deprotecting, and the structural formula of the load type chiral catalyst is shown as follow. The invention discloses the preparation method of the load type chiral catalyst. The load type chiral catalyst can realize the advantages of separability and recyclability besides being capable of obtaining high-stereoselectivity chiral products in asymmetric catalyzing reaction, and production cost is reduced.

Description

technical field [0001] The invention belongs to the field of polymer catalysts and their synthesis, and in particular relates to a supported chiral catalyst and a preparation method thereof. Background technique [0002] Chiral catalysis is widely used in the research and production of organic chemistry and fine chemical industry, but one of the main problems of chiral catalysis is that the catalyst and the reaction mixture are not easy to separate and reuse, and the extra separation process of recovering the catalyst will generate a large amount of waste. Immobilized chiral catalysts are one of the ways to solve the problem of difficult separation of homogeneous catalysts. People try to use different physical or chemical methods to combine homogeneous catalysts with supports to prepare immobilized homogeneous catalysts, hoping to maintain the characteristics of high activity and high selectivity of homogeneous catalysts, and at the same time have the characteristics of eas...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J31/06C07B53/00
Inventor 李新娟胡志国贾献彬李盛夏武大中
Owner HENAN NORMAL UNIV
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