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Method for producing esters of 2-methyl-4-chlorophenoxyacetate

A technology of chlorophenoxyacetic acid and sodium chloroacetate, which is applied to the preparation of carboxylic acid esters, chemical instruments and methods, and the preparation of carboxylate salts. Pollution and other issues, to achieve the effect of product stability, environmental friendliness and high safety operability

Inactive Publication Date: 2018-11-02
ANHUI HUAXING CHEM IND CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Now widely used are preparations prepared by salts and esters of 2-methyl-4-chlorophenoxyacetic acid, but there are still many defects in the existing preparation methods, which cannot fully guarantee that no dioxins are produced. It is a highly toxic substance, even at a very low amount of a few parts per billion, it will cause poisoning to humans, animals and plants; secondly, the operation is lengthy, the cost is high, and the preparation process is likely to cause serious pollution to the surrounding environment

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] 1) Chloroacetic acid is added to the reactor, and 80% sodium carbonate solution is added dropwise for neutralization reaction to generate sodium chloroacetate;

[0025] 2) Add o-cresol to another reaction kettle, control the temperature at 25-40°C, and keep the pressure at normal pressure. The reaction time is 25-35 minutes. Add 30% sodium hydroxide solution dropwise to react to generate sodium o-cresol, and the reaction is completed followed by insulation treatment;

[0026] 3) Sodium chloroacetate is added dropwise in the sodium o-cresate reaction kettle through a metering tank, and generates sodium o-tolylphenoxyacetate by condensation reaction;

[0027] 4) Transfer sodium o-methylphenoxyacetic acid into the chlorination reactor, add hydrochloric acid to acidify to generate o-methylphenoxyacetic acid crystals, wash with water to remove the salt in the o-methylphenoxyacetic acid crystals, and then add toluene to the reactor , Stir and heat up to 50°C and start to pas...

Embodiment 2

[0031] 1) Chloroacetic acid is added to the reactor, and 80% sodium carbonate solution is added dropwise for neutralization reaction to generate sodium chloroacetate;

[0032] 2) Add o-cresol to another reaction kettle, control the temperature at 25-40°C, and keep the pressure at normal pressure. The reaction time is 25-35 minutes. Add 30% sodium hydroxide solution dropwise to react to generate sodium o-cresol, and the reaction is completed followed by insulation treatment;

[0033] 3) Sodium chloroacetate is added dropwise in the sodium o-cresate reaction kettle through a metering tank, and generates sodium o-tolylphenoxyacetate by condensation reaction;

[0034] 4) Transfer sodium o-methylphenoxyacetic acid into the chlorination reactor, add hydrochloric acid to acidify to generate o-methylphenoxyacetic acid crystals, wash with water to remove the salt in the o-methylphenoxyacetic acid crystals, and then add toluene to the reactor , Stir and heat up to 50°C and start to pas...

Embodiment 3

[0038] 1) Chloroacetic acid is added to the reactor, and 80% sodium carbonate solution is added dropwise for neutralization reaction to generate sodium chloroacetate;

[0039] 2) Add o-cresol to another reaction kettle, control the temperature at 25-40°C, and keep the pressure at normal pressure. The reaction time is 25-35 minutes. Add 30% sodium hydroxide solution dropwise to react to generate sodium o-cresol, and the reaction is completed followed by insulation treatment;

[0040] 3) Sodium chloroacetate is added dropwise in the sodium o-cresate reaction kettle through a metering tank, and generates sodium o-tolylphenoxyacetate by condensation reaction;

[0041] 4) Transfer sodium o-methylphenoxyacetic acid into the chlorination reactor, add hydrochloric acid to acidify to generate o-methylphenoxyacetic acid crystals, wash with water to remove the salt in the o-methylphenoxyacetic acid crystals, and then add toluene to the reactor , Stir and heat up to 50°C and start to pas...

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Abstract

The invention relates to the technical field of herbicides and particularly relates to a method for producing esters of 2-methyl-4-chlorophenoxyacetate. The method comprises the following steps: adding chloroacetic acid to a reactor, and dropwise adding a 80% sodium carbonate solution to perform neutralization reaction to generate sodium chloroacetate; adding o-cresol to another reactor, dropwiseadding a 30% sodium hydroxide solution to perform reaction to generate sodium o-cresolate, and after the reaction is completed, performing thermal insulation treatment; and dropwise adding sodium chloroacetate to the sodium o-cresolate reactor through a metering tank, and performing condensation reaction to generate sodium o-phenoxyacetate and the like. The method provided by the invention has theadvantages that the cost of the product is low, the product is environmentally friendly, the technology is advanced and mature, and the safety operability is high; the total yield of esters of 2-methyl-4-chlorophenoxyacetate is greater than or equal to 93%; and the product does not contain dioxin.

Description

technical field [0001] The invention relates to the technical field of herbicides, in particular to a method for producing esters of 2-methyl-4-chlorophenoxyacetic acid. Background technique [0002] 2-Methyl-4-chlorophenoxyacetic acid is a phenoxyacetic acid herbicide with high efficiency, low toxicity and high selectivity. It is mainly used to control weeds in rice, wheat, corn, sorghum and other cereal crops. , safe for cereal crops. 2-Methyl-4-chlorophenoxyacetic acid herbicide has strong systemic conductivity. It is absorbed through the stems, leaves and roots of weeds and transmitted to various parts, destroying the dredging tissue of plants and affecting the normal physiological functions of plants. Eventually the plant dies. [0003] Now widely used are preparations prepared by salts and esters of 2-methyl-4-chlorophenoxyacetic acid, but there are still many defects in the existing preparation methods, which cannot fully guarantee that no dioxins are produced. It ...

Claims

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Application Information

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IPC IPC(8): C07C69/712C07C67/08C07C51/02C07C51/367C07C59/125C07C37/66C07C39/235C07C51/41C07C53/16
CPCC07C37/66C07C51/02C07C51/367C07C51/412C07C67/08C07C53/16C07C39/235C07C59/125C07C69/712
Inventor 王玉贵李霞赵龙凯金奎尹仕兵汪志稳
Owner ANHUI HUAXING CHEM IND CO LTD
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