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A kind of synthetic method of high-purity high-yield 1-2-chloropropionic acid

A synthetic method, the technology of chloropropionic acid, applied in the direction of chemical instruments and methods, carboxylate preparation, organic compound preparation, etc., to achieve the effect of reducing COD, high processing difficulty, and reducing three wastes

Inactive Publication Date: 2021-02-05
NANJING REDSUN BIOCHEM CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The traditional diazotization reaction uses the hydrochloric acid / sodium nitrite reaction system. First, the nitrosyl ion generated attacks the amino group with a lone pair of electrons, and generates chlorine azide through electron pair transfer, and then the temperature rises to release nitrogen gas to form a product. The aliphatic amino group is relatively active in the aqueous solution and can be easily converted into a hydroxyl group. The diazonium reaction of L-alanine in this system can only generate about 70% of the product

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] In a 500ml three-necked flask (equipped with a thermometer and a stirring paddle), add 8.9g of L-alanine (0.1mol), 50.7g of concentrated hydrochloric acid (mass fraction 36%), stir to dissolve, control the temperature at about 0°C, and pass into Mixed gas of nitrosyl chloride and hydrogen chloride, after the conversion of raw materials is complete, stop ventilation, the molar ratio of nitrosyl chloride and L-alanine is 1.2:1, feed hydrogen chloride gas to saturate hydrochloric acid; continue stirring for 1 hour, then add in batches 11.8g of sodium carbonate solid was then extracted with dichloromethane (50ml*3), the organic phases were combined, added 5g of anhydrous calcium chloride to dry, filtered and rectified to obtain 10.1g of L-2-chloropropionic acid (yield 93.1 %, ee value 98.5%).

Embodiment 2

[0023] In a 500ml three-neck flask (equipped with a thermometer and a stirring paddle), add 8.9g of L-alanine (0.1mol), 90.3g of hydrochloric acid (mass fraction 20%), stir to dissolve, control the temperature at about 5°C, and introduce nitrous acid Acyl chloride and hydrogen chloride mixed gas, after the conversion of the raw materials is complete, stop ventilation, the molar ratio of nitrosyl chloride and L-alanine is 1.2:1, feed hydrogen chloride gas to make the hydrochloric acid saturated; after continuing to stir for 1 hour, add 11.8 g sodium carbonate solid, then extracted with dichloromethane (50ml*3), combined the extracts, added 5g anhydrous calcium chloride to dry, filtered, and rectified to obtain 10g L-2-chloropropionic acid (yield 92.2%, ee value 98.3%).

Embodiment 3

[0025] In a 500ml three-necked flask (equipped with a thermometer and a stirring paddle), add 8.9g of L-alanine (0.1mol), 90.3g of hydrochloric acid (mass fraction 20%), stir to dissolve, control the temperature at about 0°C, and introduce nitrous acid Acyl chloride and hydrogen chloride mixed gas, after the conversion of the raw materials is complete, stop ventilation, the molar ratio of nitrosyl chloride and L-alanine is 1.5:1, feed hydrogen chloride gas to make the hydrochloric acid saturated; after continuing to stir for 1 hour, add 140g of Ammonia (mass fraction is 20%), then extract (50ml*3) with dichloromethane, combine extract, add 5g anhydrous calcium chloride after drying, filter, rectification obtains 10.2g L-2-chloropropionic acid ( Yield 94.0%, ee value 98.7%).

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Abstract

The invention discloses a synthesis method of L-2-chloropropionic acid. Firstly, L-alanine is dissolved in hydrochloric acid, and nitrosyl chloride is introduced to react with hydrogen chloride gas. ~2 hours, then add alkaline reagents to neutralize, extract with organic solvent, combine organic phases, dry with anhydrous calcium chloride, filter, and rectify to obtain the product L-2-chloropropionic acid. The method of the present invention has the advantages of simple operation and reduced waste water discharge. Using nitrosyl chloride with higher activity as a diazotization reagent can quickly convert aliphatic amino groups into chlorine, which greatly improves the conversion rate of raw materials and the production efficiency. The yield can reach more than 90%. During the reaction process, the original configuration is not reversed, and the optical purity ee value can reach 99.1%.

Description

technical field [0001] The invention belongs to the field of fine chemical industry and relates to a method for synthesizing L-2-chloropropionic acid with high purity and high yield. Background technique [0002] L-2-chloropropionic acid is a key intermediate for the preparation of phenoxy series herbicides, Dexibuprofen, and high-2,4-dipropionic acid herbicides. Its enantiomers exist in the form of competitive inhibitors, which will not only reduce the efficacy of the pesticide, but also reduce the quality of the pesticide, produce toxic and side effects, and lead to phytotoxicity or drug resistance. Therefore, L with higher optical activity is synthesized. -2-chloropropionic acid is of great importance. [0003] At present, the method for synthesizing L-2-chloropropionic acid mainly contains the following kinds: [0004] Method 1: Use propionic acid as a raw material, chlorinate with chlorine gas to obtain racemic 2-chloropropionic acid, and then split to obtain opticall...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C51/363C07C53/19
CPCC07C51/363C07C53/19
Inventor 丁永山袁意王福军蒋剑华陈新春
Owner NANJING REDSUN BIOCHEM CO LTD
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