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A method for preparing high-purity l-menthone and a catalyst system for the method

A technology of menthone and isopulegol, which is applied in the field of preparation of menthone, achieves the effects of convenient recycling, high yield, remarkable operability and economical efficiency

Active Publication Date: 2022-01-07
WANHUA CHEM GRP CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] The purpose of the present invention is to provide a method for continuously preparing high-purity L-menthone, so as to solve many problems existing in the existing preparation of menthone technology. The present invention utilizes ruthenium complexes and N-methanol The synergistic effect of imidazole-β-cyclodextrin chiral ionic liquid catalyzes the preparation of L-menthone from L-isopulegol with high yield, without the need to introduce an external hydrogen source. The process is safe, and the mixed solution of ionic liquid and catalyst is easy to recover and apply mechanically. Has good prospects for industrialization

Method used

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  • A method for preparing high-purity l-menthone and a catalyst system for the method
  • A method for preparing high-purity l-menthone and a catalyst system for the method
  • A method for preparing high-purity l-menthone and a catalyst system for the method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0072] Weigh 4g (3.52mmol) of β-cyclodextrin and 2g (10.56mmol) of p-toluenesulfonyl chloride, dissolve in 20mL of saturated alkaline aqueous solution of sodium hydroxide, stir at room temperature for 10 hours under nitrogen atmosphere, and recrystallize from acetone 3 times , dried in vacuum; 3.85g of white compound a was obtained, 1 HNMR(300MHz,DMSO-d6):2.34(t,3H,-CH 3 -Ts),3.20~3.67(br,m,42H,-CH),4.47(m,6H,OH),4.82~4.86(br,d,7H,-CH),5.68~5.79(br,m,14H ,OH), 7.07(t,2H,-CH-Ts), 7.27(t,2H,-CH-Ts).

[0073] Weigh 3g (0.234mmol) of dry compound a and 2g of potassium iodide (18.06mmol) and dissolve it in 60mL of DMF that has been dehydrated through 5A molecular sieves, heat to 90°C under nitrogen atmosphere and stir at constant temperature for 15 hours, then distill off the solvent under reduced pressure , add 15mL deionized water to dissolve, use 300mL acetone to precipitate the product, repeat three times to remove unreacted potassium iodide, filter, and dry under vacuum at 5...

Embodiment 2

[0076] Soak D201 resin in 95% ethanol and stir for ten minutes. After stirring, let it stand for half an hour, remove the supernatant, wash with deionized water three times, and dry the resin at 50°C until the weight is constant.

Embodiment 3

[0078] Soak D301 resin in 95% ethanol and stir for ten minutes. After stirring, let it stand for half an hour, remove the supernatant, wash with deionized water three times, and dry the resin at 50°C until the weight is constant.

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Abstract

A method for preparing high-purity L-menthone and a catalyst system used in the method. The invention discloses a method for preparing and synthesizing chiral menthone enantiomers L-menthone and D-isopulegone from L-isopulegol. The method of menthone and the catalyst system used for the method, the method is that L-isopulegol generates molecular Internal hydrogen transfer, the addition of chiral ionic liquid significantly improves the selectivity of L-menthone, and then further obtains high-purity L-menthone by reactive distillation.

Description

technical field [0001] The invention belongs to the field of menthone preparation, and in particular relates to the preparation of high-purity L-menth by synergistic catalysis of L-isopulegol through a ruthenium complex and N-methylimidazole-β-cyclodextrin chiral ionic liquid A method for ketones and a catalyst system for use in the method. Background technique [0002] Menthone, also known as menthone, has the cool and characteristic aroma of natural mint. Menthone exists as two stereoisomers: menthone and isomenthone, each of which exists as two enantiomers. Menthone is used in daily chemical, food, medicine and other industries, and can produce and deploy mint and flower flavor essences; at the same time, various derivatives can be prepared through it, so the synthesis of menthone has always attracted people's attention. [0003] Patent US3124614 reports that menthone can be obtained by hydrogenating thymol under the action of Pd catalyst, but the raw material thymol is...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C45/51C07C49/407B01J31/02B01J31/22B01J31/30
CPCC07C45/512B01J27/13B01J31/0285B01J31/2234B01J31/2295B01J31/30C07C2601/14B01J2531/821B01J35/19C07C49/407
Inventor 方文娟王联防董菁张永振黎源王亚新于磊
Owner WANHUA CHEM GRP CO LTD