Method for producing 2-methyl-4-chlorophenoxyacetic acid esters

A technology of methylphenoxyacetic acid and chlorophenoxyacetic acid, which is applied in the preparation of carboxylic acid esters, chemical instruments and methods, and the preparation of organic compounds, can solve the problems of environmental pollution, cumbersome operation, and high cost, and achieve high yields , Good product quality and easy operation

Active Publication Date: 2010-12-22
JIANGSU GOOD HARVEST WEIEN AGROCHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, these two methods need to separate 2-methyl-4-chlorophenoxyacetic acid through filtration to separate the solid and then esterify, which not only is cumbersome to operate, pollutes the environment, but also costs a lot

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] Add 2-methylphenoxyacetic acid 457.3kg (content 98%, 2.7kmol), phenothiazine 0.3kg (content 99%), dimethylaminopyridine 0.9kg (content 99%) and isobutanol in 3000L reactor 1600L, heat up to 80-85°C and stir to dissolve. Maintain the reaction temperature at 80-85° C., feed about 200 kg of chlorine gas into the material at a rate of 70-80 kg / hr, and when the content of 2-methylphenoxyacetic acid in the raw material monitored by HPLC is less than 1%, the chlorination reaction ends. Put 3kg of p-toluenesulfonic acid into the kettle, heat up and azeotropically dehydrate, until no azeotropic water is released, the reaction is considered complete. After the esterification reaction is completed, cool down to 60°C, add 100kg of water to wash and stir well, then let it stand still, and remove the lower water layer; remove the excess isobutanol solvent from the organic layer under reduced pressure to obtain the finished product 2-methyl-4-chlorophenoxy 686.6 kg of butyl acetate, ...

Embodiment 2

[0028] Add 2-methylphenoxyacetic acid 457.3kg (content 98%, 2.7kmol), phenothiazine 0.3kg (content 99%), dimethylaminopyridine 0.9kg (content 99%) and isooctyl alcohol in 3000L reactor 1600L, heat up to 80-85°C and stir to dissolve. Maintain the reaction temperature at 80-85° C., feed about 200 kg of chlorine gas into the material at a rate of 70-80 kg / hr, and when the content of 2-methylphenoxyacetic acid in the raw material monitored by HPLC is less than 1%, the chlorination reaction ends. Put 3kg of p-toluenesulfonic acid into the kettle, heat up and azeotropically dehydrate, until no azeotropic water is released, the reaction is considered complete. After the esterification reaction is completed, cool down to 60°C, add 100kg of water to wash and stir well, then let it stand still, and remove the lower water layer; remove the excess isooctyl alcohol solvent from the organic layer under reduced pressure to obtain the finished product 2-methyl-4-chlorophenoxy 833.8 kg of iso...

Embodiment 3

[0030] a, 2-methylphenoxyacetic acid is dissolved in alcohol solvent solvent, add catalyst phenothiazine and dimethylaminopyridine, pass into chlorine reaction;

[0031] b. Esterification reaction: After the above reaction is completed, add an esterification dehydration catalyst for azeotropic dehydration. After the esterification reaction is completed, wash with water and remove excess alcohol solvents to obtain the esters of the finished product 2-methyl-4-chlorophenoxyacetic acid .

[0032] The mass ratio of 2-methylphenoxyacetic acid and alcoholic solvent is 1: 0.5~50 (example 1: 0.5, 1: 25, 1: 50); The mass ratio of catalyst phenothiazine and dimethylaminopyridine is 1: 1~10 (example 1: 1, 1: 5, 1: 10); The total mass of catalyst phenothiazine and dimethylaminopyridine and the mass ratio of 2-methylphenoxyacetic acid are 1: 50~800 (example 1 : 50, 1: 400, 1: 800); the reaction temperature of feeding chlorine gas is 10~100°C (example 10°C, 50°C, 100°C); The ratio is 1:1~...

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Abstract

The invention discloses a method for producing 2-methyl-4-chlorophenoxyacetic acid esters. 2-methyl phenoxyacetic acid is reacted with chlorine introduced into an alcoholic solvent (corresponding to the alcoholic part of an ester target product) to form finished products of the 2-methyl-4-chlorophenoxyacetic acid esters in the presence of phenothiazine and dimethylamino pyridine catalysts. The 2-methyl phenoxyacetic acid is reacted in a reaction kettle, and the finished products of the 2-methyl-4-chlorophenoxyacetic acid esters can be directly produced without separation of the intermediate 2-methyl-4-chlorophenoxyacetic acid. The total yield of the finished products of the 2-methyl-4-chlorophenoxyacetic acid esters is improved to over 92 percent, and the content of effective ingredients is improved to over 93 percent.

Description

Technical field: [0001] The invention relates to a production method of esters of herbicide 2-methyl-4-chlorophenoxyacetic acid. Background technique: [0002] 2-Methyl-4-chlorophenoxyacetic acid is one of the earliest organic herbicide species used, and it is still the basic species of herbicides today. 2A4Cl is an excellent herbicide with the characteristics of high efficiency, low toxicity, low residue, and no pollution to the environment. It is not only a hormone-type herbicide, but also a plant growth regulator. It is still widely used now that its salts and isooctyl esters are formulated preparations. At present, the following methods are usually used in industry to produce esters of 2-methyl-4-chlorophenoxyacetic acid: [0003] 1, 2-methylphenol chlorination condensation method, that is, 2-methylphenol is chlorinated in its molten state, and then the obtained 2-methyl-4-chlorophenol is condensed with chloroacetic acid, and then the obtained 2- Methyl-4-chlorophenox...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C67/08C07C69/712B01J31/02
Inventor 郭胜江连王新星
Owner JIANGSU GOOD HARVEST WEIEN AGROCHEM
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