Method for efficiently preparing L-isopulegol from R-citronellal

A technology of isopulegol and citronellal, which is applied in the field of organic chemical synthesis, can solve the problems of large operation burden, high catalyst dosage, expensive catalyst, etc., and achieve reduction of operation frequency, simplification of follow-up operation process, high reaction rate and The effect of product selectivity

Active Publication Date: 2022-01-21
WANHUA CHEM GRP CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The amount of the catalyst is also high, and the expensive catalyst will bring a large operating burden in the post-treatment process. At the same time, it is difficult to separate the auxiliary agent from the product, and there are also the same cost problems.

Method used

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  • Method for efficiently preparing L-isopulegol from R-citronellal
  • Method for efficiently preparing L-isopulegol from R-citronellal
  • Method for efficiently preparing L-isopulegol from R-citronellal

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0046] 600g of toluene solution (chemical purity>99.5%) was distilled intermittently under a top pressure of 30kPaA in a glass laboratory tower (about 15 theoretical plates) with an inner diameter of 50mm equipped with a 0.5m 3mm*3mmθ ring triangular helical packing.

[0047] At a 3:1 reflux ratio, the bottom temperature was 96°C and the top temperature was 45°C. About 30 g of liquid distillate was withdrawn in the overhead condenser at about 5°C. Continue to extract about 500g of toluene solution (chemical purity>99.5%) under this condition, the water content is 454mgKOH / kg, and the hydroxyl value content is 33mgKOH / kg.

Embodiment 2

[0049] 600g of toluene solution (chemical purity>99.5%) was distilled intermittently under a top pressure of 30kPaA in a glass laboratory tower (about 15 theoretical plates) with an inner diameter of 50mm equipped with a 0.5m 3mm*3mmθ ring triangular helical packing.

[0050] At a 5:1 reflux ratio, the bottom temperature was 96°C and the top temperature was 45°C. About 30 g of liquid distillate was withdrawn in the overhead condenser at about 5°C. Continue to extract about 500g of toluene solution (chemical purity>99.5%) under this condition, the water content is 201mgKOH / kg, and the hydroxyl value content is 22mgKOH / kg.

Embodiment 3

[0052] About 600g of toluene solution (chemical purity>99.5%) was intermittently distilled under a top pressure of 30kPaA in a glass laboratory tower (theoretical plate number about 21) with an inner diameter of 50mm equipped with a 0.7m 3mm*3mmθ ring triangular helical packing.

[0053] At a 5:1 reflux ratio, the bottom temperature was 110°C and the top temperature was 45°C. About 42 g of liquid distillate was withdrawn in the overhead condenser at about 5°C. Continue to extract about 500g of toluene solution (chemical purity>99.5%) under this condition, the water content is mgKOH / kg, and the hydroxyl value is not detected.

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Abstract

The invention provides a method for efficiently preparing L-isopulegol from R-citronellal. The method comprises the following steps: under the action of a catalyst prepared from (S)-3, 3'-bis (2, 4, 6-triisopropyl phenyl)-1, 1'-co-2-naphthol and trimethyl indium, catalyzing R-citronellal to prepare L-isopulegol; in the preparation of the catalyst, controlling the hydroxyl value and the water content in an inert solvent to be 100-500 mgKOH / kg; in the method for preparing the L-isopulegol, controlling the hydroxyl value and the water content of an R-citronellal solution to be 100-500 mgKOH / kg. The preparation method provided by the invention can maintain high reaction rate and product selectivity and high final conversion rate.

Description

technical field [0001] The invention relates to a method for efficiently preparing L-isopulegol from R-citronellal, which belongs to the field of organic chemical synthesis. Background technique [0002] L-menthol, as a spice with a strong mint flavor, is widely used in oral care products such as toothpaste and mouthwash, daily chemical products such as shampoo and shaving liquid, foods such as chewing gum and beverages, and tobacco products due to its cooling effect At the same time, it can also be applied to external medicine for clearing heat and relieving itching, internal medicine for clearing throat and throat, and chiral inducer for synthesizing pharmaceutical intermediates. It is an important spice product in the world. [0003] L-isopulegol is an important intermediate for artificially synthesizing L-menthol. The traditional method to obtain L-isopulegol is to use citronellal to prepare by cyclization under the catalysis of Lewis acid, and usually four kinds of Mix...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C35/17C07C29/14B01J31/22
CPCC07C29/14B01J31/2213B01J2531/33C07C35/17
Inventor 王亚新董菁张永振
Owner WANHUA CHEM GRP CO LTD
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