Preparation method of L-menthol

A technology of menthol and autoclave, which is applied in the field of L-menthol preparation, can solve the problems of low L-menthol resolution efficiency and difficulty in obtaining raw materials, achieve ideal batch stability, improve synthesis efficiency, and obtain raw materials Effects that are cheap and easy to get

Inactive Publication Date: 2013-12-25
阜阳市百富安香料有限公司
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  • Summary
  • Abstract
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  • Claims
  • Application Information

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Problems solved by technology

In summary, in the current preparation methods of L-menthol, there are problems such as r

Method used

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Embodiment

[0011] Example: A preparation method of L-menthol, including the following steps: 1) Add 3-methyl-6-isopropylphenol and Raney nickel catalyst RTH211, palladium on carbon, cyclodextrin and The composite precious metal catalyst composed of Cu / SiO2 according to the ratio of 1:2:1.5:2.5, close the autoclave to seal it, then pass in hydrogen, replace the air in the autoclave 2-3 times, and finally pass in hydrogen to make The pressure in the kettle reaches 5.0~8.0MPa, the temperature is controlled at 100~150℃, and the time is 4~6h. A mixture of menthol is prepared, and D,L-menthol is obtained through rectification; 2) D,L-menthol Alcohol undergoes esterification reaction with acylating reagent under the action of alkali to prepare D,L-menthol ester; wherein acylating reagent can be selected from vinyl acetate, butyl acetate, isopropenyl acetate, acetic anhydride, ethyl acetate , P-chlorophenyl acetate, p-chlorophenyl propionate, p-chlorophenyl valerate, p-chlorophenyl n-octanoate, 2...

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Abstract

The invention discloses a preparation method of L-menthol. The preparation method comprises the following steps: 1) adding 3-methyl-6-isopropyl-phenol and a composite noble metal catalyst to a high-pressure kettle, wherein the composite noble metal catalyst is formed by the combination of a Raney nickel catalyst RTH211, palladium carbon, cyclodextrin and Cu/SiO2; closing the high-pressure kettle; filling hydrogen to replace the air in the kettle for two to three times; finally filling hydrogen to enable pressure in the kettle to be 5.0 to 8.0MPa; controlling the temperature to be 100 to 150 DEG C for 4 to 6 hours, thus obtaining a mixture of menthol; rectifying to obtain D,L-menthol; 2) performing esterification reaction on D,L-menthol and an acylation reagent under the effect of alkali so as to obtain D,L-menthol ester; 3) performing hydrolysis reaction on D,L-menthol ester under the effect of hydrolytic enzyme, thus obtaining L-menthol, wherein the hydrolytic enzyme is cellularized burkholderia cepacia (B.cepacia ATCC25416). The preparation method has the advantages that the production raw materials are simple and easy to obtain; the prepared L-menthol is high in yield and lower in cost and suitable for mass production and use.

Description

Technical field [0001] The invention belongs to the technical field of perfume production. More specifically, the present invention relates to a method for preparing L-menthol. Background technique [0002] I-menthol is not only an important additive in the pharmaceutical, food and cosmetic industries, but also an indispensable chiral precursor for the synthesis of chiral materials. The development of I-menthol is important for promoting the technological progress of my country’s fragrance industry and the pharmaceutical industry. The development of the company has important strategic significance. Natural menthol is I-menthol. Due to the influence of weather and region, the output and quality fluctuate greatly. The quality of synthetic menthol products is stable. The quality of I-menthol obtained after enantiomeric separation is The difference from natural products is very small, so it has received extensive attention in recent years. Since the 1920s, people have used various m...

Claims

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Application Information

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IPC IPC(8): C12P41/00C12P7/22C12R1/01
Inventor 宋大伟
Owner 阜阳市百富安香料有限公司
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