Preparation method of methionine

Abstract

The invention belongs to the field of chemical engineering, and discloses a methionine preparation method, the method comprises a process of contacting a CeO2 solid catalyst with 2-amino-4-methylthio butyronitrile water-containing liquid flow, the CeO2 solid catalyst is in a rod-like crystal form, the crystal diameter is 10-80 nm, and the crystal length is 100-500 nm. Furthermore, according to the process disclosed by the invention, the step of catalyzing CeO2 is only put into an amidation reaction process of hydrolyzing 2-amino-4-methylthio butyronitrile into methionine amide, then the methionine amide hydrolysate is hydrolyzed by using solid acid to prepare the methionine hydrolysate, and finally the methionine is taken out by using a carbon dioxide acidification crystallization mode. The rod-like cerium dioxide catalyst used in the method has higher catalyst activity and better anti-pollution capacity, the production process does not generate low-value byproduct salt, the cerium dioxide catalyst has longer recycling period, the methionine is high in one-time crystal extraction rate and stable in yield, industrial adaptability is achieved, and the method is suitable for industrial production. The industrial popularization and application of methionine can be realized.

Description

technical field

[0001] The invention belongs to the field of chemical industry, and in particular relates to an industrially adaptable method for preparing methionine by catalyzing 2-amino-4-methylthiobutyronitrile with rod-shaped ceria. Background technique

[0002] The chemical synthesis of methionine (MET, scientific name 2-amino-4-methylthiobutyric acid) is currently mainly through the synthesis of 2-hydroxy-4-methylthiobutyronitrile (referred to as cyanohydrin) through methylthiopropionaldehyde and hydrocyanic acid. , cyanohydrin and carbon dioxide, ammonia to synthesize hydantoin intermediates, hydantoin intermediates are hydrolyzed by inorganic alkalis to obtain methionine alkali salts, and acidified methionine alkali salts to obtain methionine; or methionine is directly combined with sodium cyanide, carbon dioxide, Ammonia and other components are used to synthesize hydantoin intermediates, and hydantoin intermediates are hydrolyzed with alkali and acidified to obtai...

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