Method for producing 2-methyl-4-MCPA

A technology of methylphenoxyacetic acid and chlorophenoxyacetic acid, applied in chemical instruments and methods, preparation of carboxylate, preparation of organic compounds, etc., can solve problems such as low product purity, increased cost, and increased environmental pollution , to achieve high yield, realize production cost, and obvious advantages in environmental protection

Active Publication Date: 2012-11-07
JIANGSU GOOD HARVEST WEIEN AGROCHEM
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  • Application Information

AI Technical Summary

Problems solved by technology

For the shortcoming that the purity of the product obtained by the aqueous phase post-chlorination method is still not high, some enterprises have developed a method for chlorination in the organic solvent toluene / dichloroethane. Although the product purity can reach 95%, the yield can only reach 75%. %, and by-products with low content
And the use of organic solvent toluene / ethylene dichloride not only increases the cost, but also increases the pollution to the environment

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] Add 2-methylphenoxyacetic acid 41g (content 98%, 0.242mol), dimethylaminopyridine 0.5g (content 99%), dimethylformamide 2.5g (content 99%) and 8% 363 g (0.726 mol) of sodium hydroxide aqueous solution was stirred and dissolved at room temperature. Maintain the reaction temperature at 20-25°C, feed about 28g of chlorine gas into the material at a rate of 5-10kg / hr, and when the content of 2-methylphenoxyacetic acid in the raw material is less than 1% as monitored by HPLC, the reaction ends. During the process of passing chlorine, 2-methyl-4-chlorophenoxyacetic acid solids were continuously precipitated. Add concentrated hydrochloric acid dropwise to adjust the pH of the material to 1-2, lower the temperature to 0-5°C, filter, and dry the filter cake to obtain 47.6g of 2-methyl-4-chlorophenoxyacetic acid as a white solid, the active ingredient being 2-methyl The content of base-4-chlorophenoxyacetic acid is 97.4%, and the yield is 95.5%.

Embodiment 2

[0022] A method for producing 2-methyl-4-chlorophenoxyacetic acid, 2-methylphenoxyacetic acid is dissolved in aqueous sodium hydroxide solution, catalyst dimethylaminopyridine and dimethylformamide are added, and chlorine gas is introduced to react After the reaction is completed, the temperature is lowered to crystallize, and then separated by filtration and dried to obtain the finished product 2-methyl-4-chlorophenoxyacetic acid.

[0023] The mass ratio of 2-methylphenoxyacetic acid and compound solvent is 1: 1~100 (example 1: 1, 1: 50, 1: 100); The mass ratio of catalyst dimethylaminopyridine and dimethylformamide is 1:1~10 (example 1:1, 1:5, 1:10); the mass ratio of the total mass of catalyst dimethylaminopyridine and dimethylformamide to 2-methylphenoxyacetic acid is 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); 2-methylphenoxyacetic acid and the feeding of chlorine gas The mola...

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Abstract

The invention discloses a method for producing 2-methyl-4-MCPA. In the presence of catalyst dimethylamino pyridine and dimethyl formamide, 2-methyl -phenoxy acetic acid introduces chlorine into sodium hydroxide aqueous solution to react so as to obtain the finished product of the 2-methyl-4-MCPA. The invention has the advantages of simple operation and good environment protection property, the yield of the 2-methyl-4-MCPA is improved to be above 95%, and the content of effective ingredients is above 97%.

Description

Technical field: [0001] The invention relates to a production method 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. At present, the following methods are usually used in industry: [0003] 1. 2-methylphenol chlorination and 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 to produce. [0004] 2. Condensation of 2-methylphenol and chloroacetic acid under alkaline conditions produces 2-methylphenoxyacetic acid, which is then chlorinated with chlorine gas in the aqueous phase...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C59/70C07C51/363
Inventor 郭胜江连王新星
Owner JIANGSU GOOD HARVEST WEIEN AGROCHEM
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