L-proline immobilized temperature-responsive core-shell microgel and preparation and application thereof

A temperature-responsive, core-shell microgel technology, which is applied in the preparation of organic compounds, catalytic reactions, chemical instruments and methods, etc., can solve the problem of reduced conversion rate, poor recycling performance of core-shell microgel catalysts, and difficult recovery. and other problems, to achieve high-efficiency recovery, improve recycling performance, and increase local concentration.

Inactive Publication Date: 2019-01-18
TAIYUAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the small particle size of the core-shell microgel, it is difficult to recover it. After the catalytic reaction is completed, the remaining system aqueous solution from which the reactant is separated must be dried before the

Method used

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  • L-proline immobilized temperature-responsive core-shell microgel and preparation and application thereof
  • L-proline immobilized temperature-responsive core-shell microgel and preparation and application thereof
  • L-proline immobilized temperature-responsive core-shell microgel and preparation and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] MMA and N-boc-L-ProlA were used as comonomers, AIBN was used as an initiator, and EGDMA was used as a crosslinking agent. Weigh 1.75g ​​of MMA, 0.15g of N-boc-L-ProlA, 35.2mg of EGDMA, and 30mg of AIBN, disperse in 80mL solvent acetonitrile, transfer to a 500mL three-necked reaction flask, and stir until well mixed.

[0038] Install a fractionation column, a condenser tube and a receiving bottle, place the reaction bottle in an oil bath and heat slowly, make the reaction system boil at 90°C within 30 minutes, control the time to distill 40mL of acetonitrile within 1.5 hours, and end the reaction.

[0039] Put the reaction solution into a dialysis bag with a molecular weight cut-off of 3000, dialyze in deionized water for 72 hours, remove unreacted monomers, and freeze-dry to obtain the hydrophobic core microgel P(MMA-co-N-boc-L-ProlA) .

[0040] Take 1.0 g of the above-prepared microgel, dissolve it in 5 mL of dichloromethane, stir magnetically in an ice-water bath for...

Embodiment 2

[0055] Weigh 0.94g of MMA, 0.02g of N-boc-L-ProlA, 5.3mg of EGDMA, and 20mg of ABVN, disperse in 90mL solvent THF, transfer to a 250mL three-necked reaction flask, and stir until well mixed.

[0056] Install a distillation device, place the reaction bottle in an oil bath and heat slowly, so that the temperature of the reaction system is raised to 85°C within 40 minutes to boil, and the reaction is terminated after distilling 45mL of tetrahydrofuran within 2 hours under control.

[0057] Put the reaction solution into a dialysis bag with a molecular weight cut-off of 3000, dialyze in deionized water for 24 hours, remove unreacted monomers, and freeze-dry to obtain the hydrophobic core microgel P (MMA-co-N-boc-L-ProlA) .

[0058] Take 2.0 g of the above-prepared microgel, dissolve it in 10 mL of dichloromethane, stir magnetically in an ice-water bath for 20 min, slowly add 20 mL of a mixed solution of dichloromethane and trifluoroacetic acid with a volume ratio of 1:1, and react...

Embodiment 3

[0066] Weigh 6.0g of MMA, 0.1g of N-boc-L-ProlA, 256mg of EGDMA, and 100mg of AIBN, disperse them in 150mL of tetrahydrofuran as a solvent, transfer them into a 500mL three-necked reaction flask, and stir until they are evenly mixed.

[0067] Install a distillation device, place the reaction bottle in an oil bath and heat slowly, so that the temperature of the reaction system is raised to 85°C within 40 minutes to boil, and the reaction is terminated after controlling the time to distill 75mL of tetrahydrofuran within 2 hours.

[0068] Put the reaction solution into a dialysis bag with a molecular weight cut-off of 3000, dialyze in deionized water for 24 hours, remove unreacted monomers, and freeze-dry to obtain the hydrophobic core microgel P (MMA-co-N-boc-L-ProlA) .

[0069] Take 2.0 g of the above-prepared microgel, dissolve it in 10 mL of dichloromethane, stir magnetically in an ice-water bath for 20 min, slowly add 20 mL of a mixed solution of dichloromethane and trifluor...

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Abstract

The invention discloses an L-proline immobilized temperature-responsive core-shell microgel. Methyl methacrylate is cross-linked with 4-hydroxy-L-proline to form a hydrophobic core microgel P (MMA-co-L-ProlA) core layer, and a temperature-responsive monomer, namely N-isopropylacrylamide, is cross-linked on the core layer to form a shell layer so as to obtain the core-shell microgel adopting a P (MMA-co-L-ProlA)@PNIPAM structure. The microgel has the L-proline immobilizing amount of 0.3-0.6mmol/g, has the number average particle size of 1.55-1.80 microns, not only can efficiently and highly selectively catalyze a direct asymmetric Aldol reaction in an aqueous phase environment, but also can be recycled through simple centrifugal separation.

Description

technical field [0001] The invention belongs to the technical field of polymer catalysts, and relates to a polymer catalyst based on L-proline, in particular to a temperature-responsive micron-scale core-shell microgel immobilized with L-proline, and the microgel Preparation. Background technique [0002] L-proline has a simple structure and readily available raw materials. It is a typical chiral organic small molecule and an important chiral catalyst in the direct asymmetric Aldol reaction. [0003] Most direct asymmetric Aldol reactions need to be carried out in organic solvents, but L-proline has poor solubility in organic solvents. Therefore, when L-proline catalyzes the direct asymmetric Aldol reaction, it has the disadvantages of large amount of catalyst and low catalytic efficiency. At the same time, the catalyst is also easily deactivated during the reaction, making it difficult to reuse the catalyst. [0004] Immobilizing L-proline catalysts with carrier material...

Claims

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Application Information

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IPC IPC(8): B01J31/06C07C201/12C07C205/45C08F265/04C08F220/54
CPCB01J31/06B01J35/0013B01J2231/342C07C201/12C08F265/04C07C2601/14C08F220/54C07C205/45
Inventor 申迎华唐娱徐伟伟王琴雅姚维尚盛卫冰邱丽戴胜
Owner TAIYUAN UNIV OF TECH
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