Separation and purification method for methionine hydroxy analogue synthesized through hydrolysis of cyanohydrins

Abstract

The invention discloses a separation and purification method for methionine hydroxy analogue synthesized through hydrolysis of cyanohydrins. The method comprises the following steps: carrying out ammonification and neutralization on hydrolysate obtained by hydrolysis of 2-hydroxy-4-methylthiobutyronitrile under the action of sulfuric acid and containing the methionine hydroxy analogue, ammonium sulfate and ammonium bisulfate, allowing ammonium sulfate to be precipitated through supersaturation and carrying out layering so as to obtain an organic layer I and a water layer I containing ammonium sulfate solid; concentrating the organic layer I so as to allow ammonium sulfate solid to be precipitated, carrying out solid-liquid separation, diluting obtained liquid through addition of water so as to obtain the commercial grade methionine hydroxy analogue, mixing the precipitated ammonium sulfate solid with the water layer I containing ammonium sulfate solid, and carrying out layering so as to obtain an organic layer II and a water layer II containing the ammonium sulfate solid; and subjecting the water layer II to solid-liquid separation and drying obtained solid so as to obtain commercial grade ammonium sulfate. The method provided by the invention is simple and easily practicable and can obtain the high-quality methionine hydroxy analogue and the commercial grade ammonium sulfate, and the recovery rates of the high-quality methionine hydroxy analogue and the commercial grade ammonium sulfate are more than 99%; and in the whole process of the method, no organic solvent is used, no waste water containing salt or organic matters is discharged, and cost and energy consumption are low.

Description

technical field [0001] The invention belongs to the technical field of chemical industry and relates to a method for separating and purifying chemical products. Background technique [0002] Methionine Hydroxy Analogue (MHA) is a highly acidic liquid organic acid with 12% water content and 88% active methionine hydroxyl analogue (including at least 65% of 2-hydroxy-4-methylthio Butyric acid monomer, and 2-hydroxy-4-methylthiobutyric acid dimer and polymer with a content not exceeding 23%). In poultry feeding, methionine hydroxy analogues exhibit properties similar to those of amino acids known to act as growth stimulators and thus become important additives for animal feed. [0003] One of the synthetic methods of methionine hydroxyl analogs is cyanohydrin hydrolysis, which is to react methylthiopropionaldehyde with hydrocyanic acid to obtain 2-hydroxyl-4-methylthiobutyronitrile, which is hydrated under the action of sulfuric acid to generate 2- Hydroxy-4-methylthiobutyram...

AI Technical Summary

Problems solved by technology

The problem with this method is that the obtained ammonium sulfate entrains a relatively large amount of methionine hydroxy analogs, especially the ammonium sulfate obtained by separating and purifying the organic layer, the content of which has reached about 10%. Such ammonium sulfate Has an unpleasant smell, and has a certain viscosity, is difficult to dry, and is almost worthless, which also leads to a large loss and low yield of methionine hydroxyl analogues

This method will generate a large amount of difficult-to-treat solid waste (mainly ammonium sulfate and sodium sulfate) and saline wastewater (mainly containing sodium sulfate, ammonium sulfate and methionine hydroxyl analogs), and the method does not mention the treatment of the water layer and Treatment of Sulfates Containing Methionine Hydroxyl Analogues

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