Preparation method of calcium D,L-2-hydroxy-4-methylthiobutyrate having high purity and high bulk density

Abstract

The invention aims at the chemical industry field, and relates to a preparation method of calcium D,L-2-hydroxy-4-methylthiobutyrate having a high purity and a high bulk density. The method comprises the following steps: fully reacting a hydrocyanic acid mixed gas prepared through an Andrussow method with methylthiopropionaldehyde under the catalysis of an alkali to obtain a 2-hydroxy-4-methylthiobutyronityile system; hydrating the 2-hydroxy-4-methylthiobutyronityile system in the presence of an inorganic acid to obtain D,L-2-hydroxy-4-methylthiobutyramide; and chelating D,L-2-hydroxy-4-methylthiobutyramide with calcium oxide or calcium hydroxide to prepare calcium D,L-2-hydroxy-4-methylthiobutyrate. The method has the advantages of simple synthesis technology and easily available raw materials, the above obtained product has a large bulk density, a high purity and a good fluency, can be effectively mixed with feeds as an animal feed additive to supplement the calcium element and amino acids in the daily ration and improve the endozoic production and immunity performances, and can also be used as 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 calcium D,L-2-hydroxy-4-methylthiobutyrate, in particular to the preparation method of D,L-2-hydroxy-4-methylthiobutyramide Based on the method for preparing calcium D,L-2-hydroxy-4-methylthiobutyrate. 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 analogs have the above advantages and are gra...

AI Technical Summary

Problems solved by technology

Although methionine hydroxy analogs have the above advantages and are gradually replacing some expensive amino acids in the market, they still have the following problems: 1) It has strong corrosive and pungent odor, and is inconvenient to store, transport and use. It is necessary to use an expensive special liquid feeding system; 2) It is very viscous, and it is not easy to mix evenly in the feed premix; 3) A large amount of heat is released when it meets water, which causes the feed to become rancid during storage and transportation; it is very acidic, The pH is about 1, and it is easy to react with acid and alkali in the feed or other ingredients in the premixed feed, causing damage to the nutrients in the feed

The main problems of this method are: 1) D,L-2-hydroxy-4-methylthiobutyric acid ammonium salt is dehydrated to form D,L-2-hydroxy-4-methylthiobutyramide, and high temperature is required for rectification and purification High vacuum and harsh conditions limit large-scale industrial production; 2) The yield of calcium D,L-2-hydroxy-4-methylthiobutyrate is low, only about 70%

[0009] In addition, in the actual production of the method disclosed in the above-mentioned documents, the synthetic D,L-2-hydroxy-4-methylthiobutyric acid calcium has problems such as high viscosity, low density, poor fluency, etc., so it is difficult to fully mix with the feed , the quality of the feed is unstable, which in turn affects the feeding effect

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