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A kind of synthetic method of chlorophenoxyacetic acid or chlorophenol

The technology of a chlorophenoxyacetic acid and a synthesis method is applied in the field of synthesis of chlorophenoxyacetic acid or chlorophenol, and can solve the problems of increased product difficulty, poor chlorination selectivity, and high cost of hydrochloric acid, and can reduce the chlorination activity. , Improve chlorination selectivity, simplify the effect of chlorination process operation

Active Publication Date: 2021-01-01
SHANGHAI XIAOMING DETECTION TECH SERVICE CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

If a large amount of hydrochloric acid containing phenolic compounds is produced in the production process, the utilization rate of chlorine gas can only reach 50%, and the cost of processing this type of hydrochloric acid containing phenolic compounds is very high; only chlorine gas is used for chlorination. The selectivity of chlorination is poor, resulting in a large amount of impurities in the product, which makes it more difficult to purify the product to the required specification

Method used

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  • A kind of synthetic method of chlorophenoxyacetic acid or chlorophenol

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Effect test

Embodiment 12

[0033] Embodiment 1 2, the synthesis of 4-dichlorophenol

[0034] In a 1000 ml four-necked flask equipped with stirring, thermometer, reflux condenser and dropping funnel, add 380 g of phenol (4 moles, mass content 99%), stir and heat to 60 ° C, start to feed chlorine gas, and feed chlorine gas to 35 g (0.5 moles), start to add hydrogen peroxide (30%) dropwise, feed 355g (5 moles) to chlorine gas, add 360g (3.2 moles) to hydrogen peroxide dropwise, stop logical chlorine gas and drip hydrogen peroxide, continue to insulate for 1 hour to stop the reaction, keep warm The layers were separated, and the organic phase was cooled to obtain 646 g of the product 2,4-dichlorophenol, with a mass content of 99% detected by HPLC and a yield of 98.1%; the water phase was sent to a waste water treatment station.

Embodiment 2

[0035] The synthesis of embodiment 2 2-methyl-4-chlorophenol

[0036] Add o-cresol 218g (2 moles, mass content 99%) in a 1000 milliliter four-necked bottle equipped with stirring, thermometer, reflux condenser and dropping funnel, heat to 65 ℃, start logical chlorine gas, logical chlorine gas to 11g (0.15 mole), simultaneously drip hydrogen peroxide (content 30%), feed 85g (1.2 mole) to chlorine gas, hydrogen peroxide drips and add 80g (0.7 mole), stop logical chlorine gas and drip hydrogen peroxide, continue to insulate for 0.5 hour to stop reaction, After heat preservation and standing for stratification, the organic phase was cooled to obtain 284.3 g of the product, the mass content of which was detected by HPLC was 98.5%, and the yield was 98.2%; the water phase was sent to the wastewater treatment station.

Embodiment 3

[0037] Embodiment 3 2, the synthesis of 4-dichlorophenoxyacetic acid

[0038] In a 2000ml reaction bottle, add 1000g of phenoxyacetic acid dichloroethane solution [containing 152g (1 mole) of phenoxyacetic acid] and heat to 75°C, start to pass chlorine gas, and pass chlorine gas to 21g (0.3 mole), while adding Hydrogen peroxide (content 30%), until 80g (1.15 mol) of chlorine gas is passed into, 90g (0.80 mol) of hydrogen peroxide is added dropwise, stop the flow of chlorine gas and dropwise addition of hydrogen peroxide, continue to keep warm for 1 hour to stop the reaction, leave to stand and separate, and the organic phase is concentrated and recovered solvent to obtain 220 g of the product 2,4-dichlorophenoxyacetic acid, the mass content of which was detected by HPLC was 98.7%, and the yield was 98.3%.

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Abstract

The invention relates to a method for synthesizing chlorophenoxyacetic acid or chlorophenol. The method comprises: (1) heating and melting phenol, methylphenol, phenoxyacetic acid or 2-methylphenoxyacetic acid or adding a solvent to dissolve phenol, methylphenol, phenoxyacetic acid or 2-methylphenoxyacetic acid; and (2) heating the material obtained in the step (1) to achieve a reaction temperature, introducing chlorine gas, adding hydrogen peroxide when the introduced chlorine gas accounts 2-50% of the total introducing amount, and oxidizing hydrogen chloride to generate chlorine gas so as to be recycled. According to the present invention, with the synthesis method, the amount of the by-produced hydrogen chloride is substantially reduced, and the chlorination selectivity of the late-stage reaction is improved.

Description

technical field [0001] The invention belongs to the field of organic synthesis, in particular to a method for synthesizing chlorophenoxyacetic acid or chlorophenol. Background technique [0002] 2,4-dichlorophenol and 2-methyl-4-chlorophenol (or phenoxyacetic acid and 2-methylphenoxyacetic acid) are the main synthetic raw materials of herbicides, which react with chloroacetic acid (or chlorination reaction) The obtained products are important herbicides 2,4-D, 2-methyl-4-chloro. Phenoxyacetic acid herbicide has a history of several decades, and its traditional production process includes the following two: [0003] One is direct chlorination with phenol or o-cresol. Disclosed as CN 104529757A is a kind of continuous production herbicide 2, the method for 4-dichlorophenoxyacetic acid (common name 2,4-D), with phenol and chlorine as raw material, carry out continuous chlorination reaction by microchannel reactor Prepare 2,4-dichlorophenol, then use a series of condensation ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C37/62C07C39/30C07C39/28C07C51/363C07C59/70
CPCC07C37/62C07C51/363C07C39/30C07C39/28C07C59/70
Inventor 周庆江谢思勉田晓宏
Owner SHANGHAI XIAOMING DETECTION TECH SERVICE CO LTD
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