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A kind of preparation method of dl-lysine

A technology of lysine and lysine salts, applied in the preparation of organic compounds, cyanide reaction preparation, chemical instruments and methods, etc., can solve the problem of DL-lysine with low purity, high cost, and difficulty in long-term storage problems, to achieve the effect of easy mass production, short racemization time and good decolorization effect

Inactive Publication Date: 2016-06-15
WUHAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Natural lysine and lysine produced by fermentation are mostly in L configuration, which cannot meet the needs of lysine pyrin production, so the preparation of DL-lysine is particularly important
[0004] DL-lysine can be directly synthesized from dihydropyran as a raw material. This method is not only costly, but also seriously polluting, and is not suitable for large-scale production; it can also be directly racemized to obtain DL-lysine from fermented L-lysine. However, free L-lysine is prone to yellowing and deterioration due to free amino groups, and it is difficult to preserve for a long time. Moreover, L-lysine is also prone to deterioration in the production process, and the purity of DL-lysine obtained is not high.
[0005] In the traditional lysine production process, activated carbon is generally used for decolorization. The decolorization effect of activated carbon is not ideal, and it also has a certain adsorption effect on lysine.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] Into the 1000mL flask, add 120.0gL-lysine hydrochloride, 700mL of 90% aqueous acetic acid (i.e. CH 3 COOH: H 2 O=9:1, v / v), then stir until L-lysine hydrochloride is completely dissolved, add 15mL salicylaldehyde as a catalyst to the solution to form a reaction solution; React for 1 h; then spin the reaction solution to dryness under reduced pressure, wash the residual solid with ethanol, redissolve the obtained solid in 150 mL of water, concentrate, add 80 mL of ethanol for recrystallization, and obtain DL-lysine salt as a solid. Dissolve the filtered DL-lysine salt solid in 130 mL of water, and put it on a sodium-type 732 cation exchange resin column. Rinse the column with 500mL distilled water first, then elute with 2.0mol / L ammonia water, concentrate the collected DL-lysine ammonia solution under reduced pressure to syrupy state, the temperature does not exceed 50°C, add 60mL ethanol to crystallize, filter, Wash the filter cake with 60mL ethanol, and the filtrate ...

Embodiment 2

[0027] Add 120.0g of L-lysine hydrochloride and 600mL of 80% acetic acid aqueous solution to the 1000mL flask in sequence, then stir until the L-lysine hydrochloride is completely dissolved, and add 15mL of salicylaldehyde as a catalyst to the solution , to form a reaction solution; the reaction solution was heated to 90°C, and racemized for 2 hours; then the reaction solution was spin-dried under reduced pressure, and the residual solid was washed with ethanol, and the obtained solid was re-dissolved in 150 mL of water, concentrated and recrystallized by adding 80 mL of ethanol, DL-lysine salt was obtained as a solid. Dissolve the filtered DL-lysine salt solid in 130 mL of water, and put it on a sodium-type 732 cation exchange resin column. Rinse the column with 500mL distilled water first, then elute with 2.0mol / L ammonia water, concentrate the collected DL-lysine ammonia solution under reduced pressure to syrupy state, the temperature does not exceed 50°C, add 60mL ethanol ...

Embodiment 3

[0029] Add 120.0gL-lysine hydrochloride and 800mL acetic acid aqueous solution with a volume fraction of 85% in sequence to a 1000mL flask, then stir until the L-lysine hydrochloride is completely dissolved, and add 45mL salicylaldehyde as a catalyst to the solution , to form a reaction solution; the reaction solution was heated up to 100°C, and racemized for 2 hours; then the reaction solution was spin-dried under reduced pressure, and the residual solid was washed with ethanol, and the obtained solid was dissolved in 150 mL of water, concentrated and recrystallized by adding 80 mL of ethanol to obtain DL-lysine salt solid. Dissolve the filtered DL-lysine salt solid in 150 mL of water, and put it on a sodium-type 732 cation exchange resin column. Rinse the column with 500mL distilled water first, then elute with 2mol / L ammonia water, concentrate the collected DL-lysine aqueous solution under reduced pressure to a syrupy state, the temperature does not exceed 50°C, add 60mL et...

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Abstract

The invention provides a method for preparing DL-lysine using chiral lysine salts as raw materials, specifically dissolving chiral lysine salts in aqueous acetic acid solution, adding salicylaldehyde or benzaldehyde as a catalyst, After the racemization was completed, the solvent was distilled off under reduced pressure, washed with ethanol to obtain DL-lysine salt, desalted by ion exchange column, concentrated, and decolorized to obtain DL-lysine solid. The production cost of the present invention is low, the process is simple, and the production process is not easy to be polluted. The racemization rate of L-lysine hydrochloride can reach 100% under the conditions of the method, and the purity of the obtained DL-lysine product is above 98%. .

Description

technical field [0001] The invention relates to a method for preparing DL-lysine, in particular to a method for preparing DL-lysine by using chiral lysine salt as a raw material through racemization and desalting. Background technique [0002] The common methods of amino acid racemization mainly include: (1) long-time (usually 150h) high-temperature heating for racemization in a strong acid or strong base medium, (2) sealing reaction in a strong acid or strong base medium at 150-250 degrees Celsius High-pressure racemization in the device, (3) using resin as a catalyst, racemization after the reaction of left-handed amino acids with pyridoxal and transition metal ions, etc. Most of these methods are time-consuming, power-consuming, and have harsh reaction conditions, such as high temperature and high pressure. Dangerous and not environmentally friendly, the introduction of transition metal ions is likely to cause residues of transition metal ions in the product. [0003] DL...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C227/36C07C227/42C07C229/26
Inventor 郭鹏姚里程
Owner WUHAN UNIV
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