Synthesis method of menthyl amide cooling agent

Abstract

The invention relates to a synthesis method of a menthyl amide cooling agent, which comprises the following steps of: adding L-menthyl formonitrile, alcohol and acid into a four-opening flask in a molar ratio of 1:(2-5):(1-4); returning flow while stirring, and enabling reaction for 2-6 hours; cooling, adding saturated sodium bicarbonate to neutrality, and recycling the alcohol; cooling, washing, standing for layering, drying, and collecting organic layer to obtain L-menthyl formate; adding L-menthyl formate, substituted ammonia and basic catalyst at a molar ratio of 1:(2-10):(0.01-0.2) into a four-opening flask; returning flow for 5-12 hours, and washing; and adding an organic solvent and crystallizing to obtain the product, wherein the content of the product is 99.5%, and the yield is 88%. The method provided by the invention causes little three wastes, and is safe to operate and simple in technology; excessive ammonia in reaction can be recycled, being green and environment-friendly; and the product has lasting cool feel and pure aroma.

Description

technical field [0001] The invention relates to the technical field of preparation of cooling agents, in particular to a method for synthesizing menthamide-based cooling agents. Background technique [0002] Menthamide cooling agent is a derivative of traditional cooling agent menthol. Compared with menthol, it has a stronger cooling effect and stability so that it is widely used in food, medicine, daily chemical, tobacco and other industries. [0003] The currently reported process for synthesizing menthyl amide cooling agents with mentha nitrile as an intermediate is to hydrolyze L-menth caronitrile into L-menth formic acid and then amidate to obtain the target product, or use L-menth caronitrile as a raw material The target product was obtained by Ritter reaction. [0004] For example, the patent WO2010019730A1 discloses that the synthetic route of Procter & Gamble Company of the United States is to hydrolyze L-menthyl formic acid under alkaline conditions to produce L-m...

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Problems solved by technology

[0004] For example, the patent WO2010019730A1 discloses that the synthetic route of Procter & Gamble Company of the United States is to hydrolyze L-menthyl formic acid under alkaline conditions to produce L-menthyl chloride, and then react with different substituted ammonia to obtain different Kind of WS series cooling agent; the disadvantage of this route is that it produces more three wastes, poor safety and complicated process

[0005] For example, Wang Sanyong, Li Chunrong, Cao Gan and others reported using L-menthol formamide as an intermediate in the No. 1 "Synthesis Research of New Cooling Agent N-Ethyl-L-Menthanyl Formamide" in February 2005 of fragrance and flavor cosmetics. WS-3 is obtained by reacting the body with diethyl sulfate and triacetin, and its total synthetic yield is only 41.3%. The disadvantage of this process is that the intermediate L-menthacarbonitrile is difficult to complete the reaction, and triacetin is difficult to handle , leading to complex and cumbersome process, low yield, high cost and high labor intensity

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