Technology for continuously and rapidly synthesizing methionine by cyanohydrins method

Abstract

The invention provides a technology for continuously and rapidly synthesizing methionine by a cyanohydrins method. The technology for continuously and rapidly synthesizing the methionine by the cyanohydrins method comprises the steps that (1) ammonolysis reaction is carried out, specifically, ammonia and 2-hydroxy-4-methyl sulfide butyronitrile are pumped into a micro channel reactor for ammonolysis reaction, the reaction temperature is controlled at 60-200 DEG C, the standing time of a reactant is 0.5-8.0 min, and a 2-hydroxy-4-methyl sulfide butyronitrile water solution is obtained; and (2)alkaline hydrolysis reaction is carried out, specifically, the 2-hydroxy-4-methyl sulfide butyronitrile water solution in the step (1) and alkali are simultaneously added into the micro channel reactor for reaction, the reaction temperature is controlled at 80-200 DEG C, pressure is 1.0-2.5MPa, the reaction standing time is for 10-60 min, and DL-methionine is obtained through aftertreatment. According to the technology for continuously and rapidly synthesizing the methionine by the cyanohydrins method, the methionine is prepared by adopting an ammoniation and without catalysis alkaline hydrolysis technology, and the preparation technology of the methionine is simplified; and ammoniation and alkaline hydrolysis reaction is carried out by adopting the micro channel reactor under the condition of without a catalyst, the reaction time is quick, the yield is high, raw material pyrolytic polymer and secondary reaction products affecting the product yield and quality are greatly reduced, andreduction of the cost of the methionine in industrialization and improvement of the quality of the methionine in the industrialization are facilitated.

Description

technical field [0001] The invention relates to the field of chemical industry, in particular to a process for continuously and rapidly synthesizing methionine by a cyanohydrin method. Background technique [0002] Methionine, also known as methionine, is one of the basic units of protein. It is the only amino acid containing sulfur among the essential amino acids. In addition to participating in the transfer of methyl groups in animals, the metabolism of phosphorus and the synthesis of adrenaline, choline, and creatine In addition, it is also a raw material for the synthesis of protein and cystine. Methionine is widely used in the fields of medicine, food, feed and cosmetics, among which the largest amount is used as a feed additive. In 2018, the demand for methionine in my country reached about 230,000 tons, and the import volume reached nearly 180,000 tons, nearly 80% of which The demand depends on imports, and the domestic production capacity of methionine is only 150,00...

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Problems solved by technology

[0006] In view of the above-mentioned shortcoming of the prior art, the object of the present invention is to provide a kind of technique of cyanohydrin method continuous rapid synthesis methionine, this method possesses atom economy, utilizes microchannel reactor technology to be used to solve 2 in the prior art -Hydroxy-4-methylthiobutyronitrile ammoniation is easy to thermally polymerize, decompose and produce the problem of by-product methionine dinitrile, and utilize microchannel reactor alkali hydrolysis 2-amino-4-methylthiobutyronitrile to solve the present problem In the existing technology, the hydrolysis cannot be complete, and a large amount of acetone needs to be used, resulting in many by-products, a slow reaction rate, resulting in the formation of colored impurities, insufficient reaction, no economic and economic efficiency, resulting in waste of resources, not green and environmental protection, etc.

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