Clean preparation method of high-purity methionine hydroxyl analogue calcium salt

Abstract

The invention discloses a clean preparation method of high-purity methionine hydroxyl analogue calcium salt. The clean preparation method comprises the following specific steps: adding water into 2-hydroxy-4-methylthiobutyronitrile serving as a raw material, carrying out a hydration reaction under the catalytic action of solid acid/solid alkali, adding strong acid or strong alkali for hydrolysis to obtain 2-hydroxy-4-methylthiobutyric acid, then adding CaO or Ca(OH)2, carrying out a salt forming reaction to obtain an aqueous solution of a mixture, carrying out chromatographic desalination treatment on the aqueous solution of the mixture to obtain an aqueous solution of a methionine hydroxyl analogue, and finally carrying out spray drying on the aqueous solution of the methionine hydroxyl analogue to obtain a target product. Compared with a traditional method, the method disclosed by the invention has the advantages that the step of neutralizing and alkali washing after the reaction is finished is avoided, the generation of a byproduct, namely inorganic ammonium salt is avoided, reaction is simple, conditions are mild, and the method is safe and environment-friendly; and in addition, a catalyst, namely the solid acid or solid alkali adopted in the method can be recycled, so production cost is reduced.

Description

technical field [0001] The invention belongs to the technical field of chemical synthesis, and in particular relates to a clean preparation method of high-purity methionine hydroxyl analogue calcium salt. Background technique [0002] The traditional method for preparing methionine is to use acrolein and methyl mercaptan as raw materials to produce methionine, and then to obtain methionine product through cyanamide reaction. [0003] J.Am used 3,6-bis-(β-chloroethyl)-2,5-diketopiperazine as raw material to react with thiourea and then dimethyl sulfate to obtain a methylthio-substituted intermediate, followed by hydrolysis Get methionine. However, the intermediates of this synthetic route need to use butyrolactone derivatives as raw materials, which can be obtained through multi-step synthetic reactions. The synthetic route is long and the yield is low, and the raw material cost is high and has no industrial value. [0004] Methionine Hydroxy Analogue (MHA) is a highly acid...

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

[0011] In conclusion, there are following defects in the preparation of high-purity methionine hydroxyl analog calcium salt in the prior art: 1) It can only be obtained through multi-step synthesis reactions, the synthesis route is long and the yield is low, and the cost of raw materials is high and has no industrial value

2) Using organic solvent extraction, not only the loss of organic solvent, but also the organic solvent and methionine hydroxy analogs will remain in the water phase, resulting in high COD in the effluent, which is difficult to handle biochemically, and the obtained methionine hydroxy analogs are also It will contain organic solvents, which must be distilled in a high vacuum state or steamed into it to reduce the content of organic solvents, all of which lead to high cost and energy consumption of the method; and it is necessary to configure the water removal rectification of organic solvents Equipment, etc., equipment investment is also relatively large

3) The obtained by-product ammonium sulfate contains a relatively large amount of methionine hydroxyl analogs, especially the ammonium sulfate obtained from the separation and purification of the organic layer, the content of methionine hydroxyl analogs has reached about 10%, so it 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 analogs

4) The recovery of organic solvents is difficult, and the amount of use and loss is large. When adding a water-miscible organic solvent such as alcohol, it will inevitably lead to an esterification reaction between the alcohol and the methionine hydroxyl analog. If the recovery of the methionine hydroxyl analog , there is a quality problem of methionine hydroxy analogs, and if it is discharged, it will lead to the loss of methionine hydroxy analogs and a large amount of hard-to-treat solid waste (mainly ammonium sulfate and sodium sulfate) and saline wastewater (mainly containing Sodium sulfate, ammonium sulfate, and methionine hydroxy analogs) pose environmental concerns

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