Method for producing ester of 2, 4-dichlorphenoxyacetic acid

A technology of dichlorophenoxyacetic acid and phenoxyacetic 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, high cost, and cumbersome operation, and achieve high yields , easy operation, good product quality

Active Publication Date: 2011-01-12
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 filter 2,4-dichlorophenoxyacetic acid to separate the solid a...

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] Add phenoxyacetic acid 420kg (content 98%, 2.7kmol), phenothiazine 0.3kg (content 99%), dimethylaminopyridine 0.9kg (content 99%) and butanol 1600L in the 3000L reactor, heat up to 80 Stir at ~85°C to dissolve. Maintain the reaction temperature at 80-85° C., feed about 400 kg of chlorine gas into the material at a rate of 70-80 kg / hr, and when the phenoxyacetic acid content of 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 butanol solvent from the organic layer under reduced pressure to obtain the finished product butyl 2,4-dichlorophenoxyacetate 744.0kg, the content of active ingredient ...

Embodiment 2

[0028] In 3000L reactor, add phenoxyacetic acid 420kg (content 98%, 2.7kmol), phenothiazine 0.3kg (content 99%), dimethylaminopyridine 0.9kg (content 99%) and isooctyl alcohol 1600L, heat up to Stir and dissolve at 80-85°C. Maintain the reaction temperature at 80-85° C., feed about 400 kg of chlorine gas into the material at a rate of 70-80 kg / hr, and when the phenoxyacetic acid content of 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 iso-octanol solvent from the organic layer under reduced pressure to obtain the finished product 2,4-dichlorophenoxyacetic acid iso 905.7kg of octyl esters, 95.1%...

Embodiment 3

[0030] a, dissolving phenoxyacetic acid in an alcoholic solvent solvent, adding catalyst phenothiazine and dimethylaminopyridine, feeding chlorine to react;

[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 solvent to obtain the finished product 2,4-dichlorophenoxyacetic acid esters.

[0032] The mass ratio of phenoxyacetic acid and alcohol solvent is 1: 0.5~50 (example 1: 0.5, 1: 25, 1: 50); the mass ratio of phenothiazine and dimethylaminopyridine is 1: 1~10 (example 1:1, 1:5, 1:10); the mass ratio of the total mass of catalyst phenothiazine and dimethylaminopyridine to phenoxyacetic acid is 1:50~800 (example 1:50, 1:4005, 1: 800); The temperature that feeds chlorine to react is 10~100 ℃ (example 10 ℃, 50 ℃, 100 ℃); The molar ratio of phenoxyacetic acid and the chlorine total amount that fee...

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PUM

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Abstract

The invention discloses a method for producing ester of 2, 4-dichlorphenoxyacetic acid, wherein the finished product of the ester of the 2, 4-dichlorphenoxyacetic acid is prepared by reacting phenoxyacetic acid with chlorine introduced into an alcohol solvent in the presences of phenothiazine and dimethylamino pyridine as catalysts. The finished product of the ester of the 2, 4-dichlorphenoxyacetic acid can be directly produced from phenoxyacetic acid in one reaction kettle, without separating the intermediate 2, 4-dichlorphenoxyacetic acid by using the method. The total yield of the finishedproduct of the ester of the 2, 4-dichlorphenoxyacetic acid can be increased to more than 95%, and the content of effective ingredients can be increased to more than 95%.

Description

Technical field: [0001] The invention relates to a method for producing esters of herbicide 2,4-dichlorophenoxyacetic acid. Background technique: [0002] 2,4-Dichlorophenoxyacetic acid is the longest-used organic synthetic herbicide species in the world, and its salts, butyl esters and isooctyl esters are still widely used in preparations. The industry usually adopts the following methods to produce the esters of 2,4-dichlorophenoxyacetic acid at present: [0003] 1. Esterification method after chlorination and condensation of phenol, that is, phenol is chlorinated in its molten state, the obtained dichlorophenol is condensed with chloroacetic acid, and then the obtained 2,4-dichlorophenoxyacetic acid is combined with the corresponding Alcohol esterification to produce. [0004] 2. Phenol and chloroacetic acid are condensed under alkaline conditions to form phenoxyacetic acid, which is then chlorinated with chlorine gas, and then produced by esterifying the obtained 2,4-d...

Claims

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Application Information

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IPC IPC(8): C07C67/08C07C69/712
Inventor 郭胜江连王新星
Owner JIANGSU GOOD HARVEST WEIEN AGROCHEM
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