A kind of synthetic method of lipoic acid intermediate

Abstract

The invention relates to a synthesis method for a thioctic acid intermediate 2-(2-ethoxyethyl)cyclohexanone, wherein hydrogen peroxide and ozone are adopted as initiators and cyclohexanone and vinyl ether are subjected to a free radical addition reaction to obtain the target product thioctic acid intermediate 2-(2-ethoxyethyl)cyclohexanone. The synthesis method is characterized in that a shell and tube reactor is used, cyclohexanone is added from a material inlet 1, uniformly mixed vinyl ether and hydrogen peroxide is added from a material inlet 2, ozone is added from a material inlet 3, a continuous mixing reaction is performed in the reactor, and the product is collected at the material outlet of the shell and tube reactor until the reaction is completely completed. With the method of the present invention, the multiple 2-(2-ethoxyethyl)cyclohexanone preparation industry problems are solved, the continuous reaction can be achieved, the automated operation is easily achieved, the reaction conditions are mild and easy to control, the product yield and the product purity are high, and the method is suitable for large-scale industrial production.

Description

technical field [0001] The invention belongs to the technical field of organic synthesis route design and preparation of raw materials and intermediates, and in particular relates to a preparation method of lipoic acid intermediate 2-(2-ethoxyethyl)cyclohexanone. Background technique [0002] 2-(2-ethoxyethyl)cyclohexanone, whose structure is shown in the following formula, is an important intermediate for the synthesis of lipoic acid. [0003] [0004] One of the reported synthetic methods of lipoic acid is to use cyclohexanone as the starting material, first carry out free radical addition with vinyl ether, then undergo Baeyer-Villiger oxidation to obtain lactone, and then ring-open the lactone to obtain dihydrogen Alpha lipoic acid, finally cyclized to obtain lipoic acid. [0005] The synthetic route of above-mentioned lipoic acid is as follows: [0006] [0007] Wherein the first step is a free radical addition reaction, using cyclohexanone and vinyl ether as raw...

AI Technical Summary

Problems solved by technology

In order to ensure the complete reaction, a large excess of cyclohexanone is added in the existing conventional production process. On the one hand, the cost is too high;

In addition, the optimized temperature of this step reaction is 140°C, the reaction time is 6-8 hours, the energy consumption is relatively high, and the yield is only about 60% (Li Chuanying et al., "Synthesis of α-lipoic acid", master's thesis of Zhejiang University , 2002)

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