Environment-friendly clean production method of D,L-methionine

Abstract

The invention discloses an environment-friendly clean production method of D,L-methionine. The method comprises the following steps: (1) D,L-methionine salt water is adopted as a raw material, and is subjected to a bipolar membrane electrodialysis treatment in a bipolar membrane electrodialysis system, wherein the pH value in a salt chamber is controlled at 5.5-6.0, such that a D,L-methionine solution is obtained, and an alkali solution is obtained in an alkali chamber; and (2) D,L-methionine separated from the D,L-methionine solution obtained in the step (1). According to the invention, acid for neutralization is not needed, such that a by-product sulfate or hydrochloride is completely eliminated. The method causes no three-waste (waste gas, waste water, and solid waste) pollution, and helps reducing salt-containing waste water treatment cost. With the method, product quality is good, and yield is high. Also, according to the invention, the D,L-methionine salt is prepared with 2-hydroxy-4-methylthiobutyronitrile direct ammoniation, alkaline hydrolysis, and ammonia removing, such that carbonate is not produced. In the subsequent bipolar membrane electrodialysis treatment, energy consumption can be saved, and production cost can be reduced.

Description

technical field [0001] The invention relates to a production method of D,L-methionine, in particular to an environmentally friendly and clean production method of D,L-methionine. Background technique [0002] D, L-methionine, also known as methionine, is one of the basic units of protein and the only sulfur-containing amino acid among essential amino acids. Its structural formula is as follows: [0003] [0004] D, L-methionine is not only involved in the transfer of methyl groups in animals, the metabolism of phosphorus and the synthesis of epinephrine, choline and creatine, but also the raw material for the synthesis of protein and cystine, so it is widely used in medicine, food and feed And cosmetics and other fields, in which it is used in a large amount as a feed additive. However, due to the limitations of technology and production costs, domestic production cannot meet the demand, and it needs to be imported from abroad. [0005] There are quite a lot of publish...

AI Technical Summary

Problems solved by technology

Sulfuric acid or hydrochloric acid acidification produces a large amount of sulfate or hydrochloride by-products, and a large amount of saline wastewater is difficult to treat, resulting in complex and cumbersome processes and high production costs, and a certain amount of D,L-methionine will be dissolved in the acidification mother liquor. Resulting in lower yields and poorer product quality

Acidification with carbonic acid, although potassium carbonate can be recycled, but in order to reduce the accumulation of impurities, a certain amount of mother liquor must be discharged regularly, resulting in the loss of D, L-methionine products. In order to obtain high-purity D, L-methionine, Need to use a lot of water to wash

[0006] It can be seen that the conventional D, L-methionine production method has many wastes, complex process, low yield and high cost, which are difficult to accept in industrial production

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