Synthesis method of 2, 4-dichlorophenoxyacetic acid compound

A technology of dichlorophenoxyacetic acid compound and dichlorophenoxyacetic acid ester, which is applied in 2 fields, can solve the problems of unfavorable industrial production, many chlorinated by-products, and incomplete conversion, so as to avoid post-processing difficulties and reaction conversion Efficiency increase, avoid hydrolysis effect

Active Publication Date: 2019-05-21
HEILONGJIANG UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to solve the problem of hydrolysis in the 2,4-dichlorophenoxyacetic acid synthesis method that first prepares phenoxide, halogenated salt or halogenated ester reaction, and the problem that there are many chlorinated by-products, and The conversion rate of phenol is low, the conversion is incomplete, causing environmental pollution problems; and the use of a large amount of solvents and the generation of a large amount of waste water, high cost, complicated process, high environmental risk, and unfavorable problems for industrialized production

Method used

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specific Embodiment approach 1

[0014] Specific embodiment one: a kind of 2 of the present embodiment, the synthetic method of 4-dichlorophenoxyacetic acid compound, it is to carry out according to the following steps:

[0015] 1. Add 2,4-dichlorophenol into the reaction flask, then add anhydrous carbonate weak base, haloacetate and catalyst; start stirring after heating and melting, and carry out condensation reaction. HPLC monitors until there is no 2,4 -Dichlorophenol, stop reaction; Obtain intermediate 2,4-dichlorophenoxyacetate;

[0016] 2. Add water to the intermediate 2,4-dichlorophenoxyacetate, heat to reflux for hydrolysis reaction, monitor to no 2,4-dichlorophenoxyacetate by HPLC, cool, add acid solution to carry out acidification reaction, After the reaction, it was lowered to room temperature, filtered, washed, and dried to obtain a white solid of 2,4-dichlorophenoxyacetic acid.

[0017] The yield of 2,4-dichlorophenoxyacetic acid obtained in this embodiment is more than 97%, the effective conte...

specific Embodiment approach 2

[0018] Embodiment 2: This embodiment differs from Embodiment 1 in that the molar ratio of 2,4-dichlorophenol to haloacetate is 1:1.2-2.0.

[0019] Others are the same as in the first embodiment.

[0020] The molar ratio of the haloacetate compound to 2,4-dichlorophenol in this embodiment is preferably 1.3˜1.5:1.0.

specific Embodiment approach 3

[0021] Embodiment 3: This embodiment differs from Embodiment 1 in that: the catalyst is one or more of polyether, crown ether, and quaternary ammonium salt.

[0022] Others are the same as in the first embodiment.

[0023] The catalyst described in this embodiment is preferably one or more of polyethylene glycols, 15-crown-4, benzyltrimethylammonium salt and tetrabutylammonium salt; more preferably polyethylene glycol di Methyl ether, tetrabutylammonium bromide salt.

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Abstract

The invention relates to a synthesis method of a 2, 4-dichlorophenoxyacetic acid compound, and relates to the technical field of organic synthesis. The synthesis method of the 2, 4-dichlorophenoxyacetic acid compound is to solve the problems of many by-products existing in synthesis method of the 2, 4-dichlorophenoxyacetic acid compound in prior art, low conversion of phenol, incomplete conversion, environmental pollution resulted, the use of a large number of solvents, production of a large amount of wastewater, high cost, complex technology, high environmental risk, and being not conducive to industrial production. According to the synthesis method of the 2, 4-dichlorophenoxyacetic acid compound, in the synergistic action of anhydrous carbonate weak base and a catalyst, performing condensation of 2, 4-dichlorophenol with halogen acetate, and 2, 4-dichlorophenoxyacetic acid is obtained directly by hydrolysis and acidification. The process of the synthesis method of the 2, 4-dichlorophenoxyacetic acid compound is accomplished by condensation, hydrolysis and acid hydrolysis in one pot without any solvent and using anhydrous carbonate weak base to react with 2, 4-dichlorophenol can effectively inhibit the hydrolysis of chloroacetate, improve the condensation conversion, reduce the content of free phenol, keep a yield over 97% an active ingredient more than 98%, and free phenol content in 50-100 ppm.

Description

technical field [0001] The invention relates to the technical field of organic synthesis, in particular to a method for synthesizing 2,4-dichlorophenoxyacetic acid. Background technique [0002] 2,4-Dichlorophenoxyacetic acid (2,4-dichlorophenoxyacetic acid, 2,4-D) is a representative plant auxin. A variety of commercial processing formulations of this compound, such as sodium salt, ammonium salt, butyl ester, isooctyl ester, etc., can be used as plant growth regulators at low concentrations, and can be used to prevent and control tomato, cotton, pineapple, etc. Seedless fruit, etc.; at high concentrations, it is mainly used as a systemic herbicide, and can be used to control broad-leaved weeds such as quinoa, amaranth, and grass weeds in the bud stage in wheat, rice, corn, sugarcane and other crop fields. The drug has low toxicity, is harmless to humans and animals, and can be mixed with various pesticides. It is one of the widely used herbicides at present. [0003] Sinc...

Claims

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Application Information

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IPC IPC(8): C07C51/09C07C59/70
Inventor 孙志忠梁朝文温立君初文毅张婉颖
Owner HEILONGJIANG UNIV
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