Method for synthesizing 3-hydroxy-2-butanone

Abstract

The invention provides a method for synthesizing 3-hydroxy-2-butanone. In a self-generated pressure reaction kettle, cheap and stable paracetaldehyde is used as raw material, thiazole salt is used as a catalyst, the catalytic synthesis of the 3-hydroxy-2-butanone by a 'one-pot' method is realized by the continuous reaction of the high-temperature depolymerization of the paracetaldehyde and the coupling condensation of acetaldehyde by catalysis, the conversion rate of the paracetaldehyde is 90-98%, and the selectivity of the 3-hydroxy-2-butanone is 85-95%. The invention has the obvious characteristics that the use of the raw material of the volatilizable acetaldehyde is avoided, the conversion rate of the raw material of the paracetaldehyde is high, the paracetaldehyde is utilized to a maximum limit, the technological operation is simple, the cost is low, the product is easy to separate, and a novel preparation method is provided for the industrial production of the 3-hydroxy-2-butanone.

Description

technical field [0001] The invention belongs to the field of fine chemical industry and relates to a method for synthesizing 3-hydroxy-2-butanone. Background technique [0002] 3-Hydroxy-2-butanone, also known as acetoin, has a pleasant creamy aroma and is used as a flavor enhancer for cream, cheese, coffee, and fruit, as a preparation for cream, dairy products, yogurt, and strawberry types, etc. Essence is also widely used in tobacco, medicine, etc., and has extremely high application value. my country's GB2760-86 stipulates that it is a food fragrance that is allowed to be used. In addition, 3-hydroxy-2-butanone is also an intermediate in the synthesis of many fragrance compounds and drugs. body. Although 3-hydroxy-2-butanone is versatile and naturally occurs in many foods such as corn, grapes, cocoa, apples, bananas, cheese, meat, etc., its content is extremely low and difficult to extract. The high-purity 3-hydroxy-2-butanone used in China is basically imported, and the ...

AI Technical Summary

Problems solved by technology

In recent years, there have been many reports on the synthesis of 3-hydroxy-2-butanone. The main preparation methods include deacidification of acetolactate, selective reduction of diacetyl, and the action of sorbobacillus or film-forming bacteria on 2,3 - Obtained by selective oxidation of butanediol, or obtained by the action of fungi such as Aspergillus and Penicillium on sugarcane juice. The above-mentioned method cannot be applied industrially due to high cost or technical requirements. Recently, it has been reported that methyl ethyl ketone is used as raw material Acetoin is prepared as an oxidizing agent with an acid salt (Chinese patent, application number: 200810143190.7), but because the process requires two steps, the reaction is complicated, the product separation is complicated, and the yield is low, it is difficult to obtain application in industry

Someone adopts acetaldehyde as raw material, prepares acetoin by coupling condensation reaction, the advantage of this method has " atom economy " feature, has realized the method for synthesizing 3-hydroxyl-2-butanone by acetaldehyde (Chinese patent, Application number: 200410021240.6), but due to the low boiling point of acetaldehyde (boiling point is 21 ℃), volatile, etc., it is difficult to transport and store, and there is a serious problem of raw material loss in the process of operation, and the volatilization of acetaldehyde not only increases Industrial cost, but also pollute the environment and unsafe factors in operation

Therefore, directly adopting acetaldehyde as raw material to prepare 3-hydroxy-2-butanone in industrial application must be subject to certain restrictions

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