A kind of technology of continuous rapid synthesis of methionine by cyanohydrin method

Abstract

The invention provides a process for continuously and rapidly synthesizing methionine by the cyanohydrin method, which includes: (1) ammoniation reaction: passing ammonia and 2-hydroxy-4-methylthiobutyronitrile into a microchannel reactor for ammoniation reaction, and controlling The reaction temperature is 60-200°C, the residence time of the reactants is 0.5-8.0min, and an aqueous solution of 2-amino-4-methylthiobutyronitrile is obtained; (2) Alkaline hydrolysis reaction: the step (1) 2-amino-4-methanol The thiobutyronitrile aqueous solution and the alkali are simultaneously added into the microchannel reactor for reaction, the reaction temperature is 80-200°C, the pressure is 1.0-2.5MPa, the reaction residence time is 10-60min, and DL-methionine is obtained after post-treatment. The invention adopts ammoniation and non-catalyzed alkaline hydrolysis process to prepare methionine, which simplifies the preparation process of methionine; selects microchannel reactor to carry out ammoniation and alkaline hydrolysis reaction under catalyst-free conditions, has fast reaction time and high yield, which affects product yield The quality and quality of raw material pyrolysis polymers and side reaction products are greatly reduced, which is beneficial to the cost reduction and quality improvement of methionine in industrialization.

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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