Preparation method of medicinal D,L-2-hydroxy-4-methylthiobutyric acid metal chelate

Abstract

The invention aims at the chemical industry field, and relates to a preparation method of a medicinal D,L-2-hydroxy-4-methylthiobutyric acid metal chelate. The method comprises the following steps: carrying out a reaction of a hydrocyanic acid mixed gas prepared through an Andrussow process and methylthiopropionaldehyde as initial raw materials to obtain a 2-hydroxy-4-methylthiobutyronityile system, hydrating the 2-hydroxy-4-methylthiobutyronityile system to obtain D,L-2-hydroxy-4-methylthiobutyramide, and hydrolyzing to obtain D,L-2-hydroxy-4-methylthiobutyrate; and chelating D,L-2-hydroxy-4-methylthiobutyrate with a trace metal element salt to obtain the D,L-2-hydroxy-4-methylthiobutyrate. The method has the advantages of mild technological conditions, few side reactions, low production cost and simple purifying operation, and the obtained D,L-2-hydroxy-4-methylthiobutyrate has a high purity and a large bulk density, and can be used as an animal feed additive or a medicinal reagent.

Description

technical field [0001] The present invention is aimed at the field of chemical engineering, and relates to a preparation method of a medicinal D,L-2-hydroxy-4-methylthiobutyric acid metal chelate, in particular to a D,L-2-hydroxy-4-methylthiobutyrate A method for preparing D,L-2-hydroxy-4-methylthiobutyric acid metal chelate on the basis of the butyrate preparation method. Background technique [0002] Methionine hydroxy analogue (MHA), also known as D,L-2-hydroxy-4-methylthiobutyric acid, is a methionine additive with low toxicity, low rumen degradation rate, promotion of rumen microbial synthesis, and saving in dietary It is the most economical and effective amino acid source for animals, with the characteristics of high protein, improving the production performance of dairy cows, improving the production performance and immunity of animals, reducing ammonia emissions, less polluting the environment, simple production process, and low price. Although methionine hydroxy an...

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Problems solved by technology

[0003] (1) It has a strong corrosive and pungent odor, and it is inconvenient to store, transport and use, so it is necessary to use an expensive special liquid feeding system;

[0004] (2) It is very viscous, and it is not easy to mix evenly in the feed premix;

[0005] (3) A large amount of heat is released when it comes into contact with water, causing the feed to heat up and ferment and become rancid during storage and transportation; the acidity is very high, with a pH of about 1, and it is easy to react with feed or other ingredients in the premixed feed. Nutrients cause damage

But this production process production cost is all higher, specifically, in order to obtain high yield, all needs purer hydrocyanic acid, and hydrocyanic acid is often excessive, the additional rectification purification of hydrocyanic acid and excessive use All will cause an increase in cost, and this increase in cost, especially on an industrial scale, will lead to huge economic losses; moreover, the unsuitability of the reaction system will also increase the burden of subsequent purification and separation, reducing the yield of the product

[0009] In addition, since the commercially available D,L-2-hydroxy-4-methylthiobutyric acid is a mixture, which contains about 22% of dimers and their polymers, and these polymers are mostly esters or anhydrides Exist in the form of these polymers, making it difficult for these polymers to react with trace metal elements, and finally adsorbed on the surface of the product, making it difficult to dry the product, which in turn affects the quality of the product

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