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Preparation method of 2,4-dichlorophenoxyacetic ester

A technology of dichlorophenoxyacetate and methyl dichlorophenoxyacetate, which is applied in the field of preparation of 2,4-dichlorophenoxyacetate, can solve the health risks of production personnel, environmental hazards, and the pressure of three wastes treatment Large and other problems, achieve the effect of simple and easy separation, improve use efficiency and save energy consumption

Inactive Publication Date: 2018-12-07
SHANDONG RUNBO BIOTECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] In the above preparation method, the intermediate product 2,4-dichlorophenol is generated, which has an extremely unpleasant pungent odor, resulting in a very poor production site environment, and the poor selectivity of chlorination leads to its low purity
[0008] In step 2) during the condensation process, the impurity dichlorophenol and polychlorinated phenol in the chlorinated phenol will condense between two molecules to generate a series of highly toxic and refractory compounds - dioxins, and then produce a large amount of dioxins containing Hazardous waste of chlorophenols and chlorophenoxyacetic acids, and dioxins are also contained in the output products, which brings great risks to the environment and the health of production personnel, and dioxins will also follow step 3) The use of prepared products enters plants, air, soil and water sources, and enriches along the food chain, causing more serious environmental hazards
[0009] At the same time, the chlorination selectivity of the above-mentioned reaction route is poor, the post-treatment process has the loss of active ingredients, the yield of the product is on the low side, and a large amount of waste water containing glycolic acid and waste salt will be produced, as well as a large amount of waste water containing chlorinated phenol and chlorinated benzene Hazardous waste of oxyacetic acid and three wastes are under high pressure and high treatment cost

Method used

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  • Preparation method of 2,4-dichlorophenoxyacetic ester
  • Preparation method of 2,4-dichlorophenoxyacetic ester
  • Preparation method of 2,4-dichlorophenoxyacetic ester

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0071] Add 42.83g99% sodium hydroxide and 142.59g xylene to 95.06g99% phenol, heat up and reflux for dehydration until moisture≤0.5%, add 116.20g99% methyl chloroacetate dropwise at 90°C to make it react, drop After the addition, keep the reaction at this temperature for 0.5h, cool down to 40°C, filter and add an appropriate amount of xylene to wash the filter cake, then dry to obtain sodium chloride and crude methyl phenoxyacetate containing xylene, and distill and recover xylene to obtain Methyl phenoxyacetate 172.02g, content 96.1%.

[0072] Add 1.72g of 99% tin tetrachloride and 0.60g of 99% 2,5-dichlorothiazole to the distilled methyl phenoxyacetate, and add 279.41g of 99% sulfuryl chloride at 60°C to make it react. Keep the reaction at high temperature for 0.5h, distill under 1kpa pressure and collect fractions at 115-125°C to obtain 234.12g of methyl 2,4-dichlorophenoxyacetate with a content of 99.18%.

[0073] Add 136.08g of 99% isooctyl alcohol and 1.87g of macroporo...

Embodiment 2

[0077] Add 69.80g99% potassium carbonate and 95.06g toluene to 95.06g99% phenol, heat up and reflux for dehydration until the water content is ≤0.5%, add 109.63g99% methyl chloroacetate dropwise at 120°C to make it react, add dropwise After completing the reaction at this temperature for 0.5h, cool down to 30°C to filter and add an appropriate amount of toluene to wash the filter cake, then dry to obtain potassium chloride and crude methyl phenoxyacetate containing toluene, and recover toluene by distillation to obtain methyl phenoxyacetate Esters 172.60g, content 95.9%.

[0078] Add 0.78g 99% ferric chloride and 1.12g 99% tert-butyl methyl sulfide to methyl phenoxyacetate, add 236.92g 99% thionyl chloride dropwise at 40°C to make it react, and keep warm at this temperature after adding After reacting for 0.5h, distill under 1kpa pressure and collect fractions at 115-125°C to obtain 235.28g of methyl 2,4-dichlorophenoxyacetate, with a content of 99.01%.

[0079] Add 75.75g of...

Embodiment 3

[0081]Add 91.65g99% sodium bicarbonate and 427.77g toluene to 95.06g99% phenol, heat up and reflux to dehydrate until the water content is ≤0.5%, add 118.40g99% methyl chloroacetate dropwise at 80°C to make it react, add dropwise After completing the heat preservation reaction at this temperature for 0.5h, cool down to 50°C to filter and add an appropriate amount of toluene to wash the filter cake, then dry to obtain sodium chloride and crude methyl phenoxyacetate containing toluene, and recover toluene by distillation to obtain methyl phenoxyacetate Esters 172.13g, content 96.0%.

[0082] Add 1.29g of 99% aluminum oxide and 0.09g of 99% tert-butyl sulfide to the methyl phenoxyacetate obtained by distillation, and pass 153.77g of 99% chlorine gas at 100°C to make it react. After adding, keep warm at this temperature for reaction After 0.5h, distill under 1kpa pressure and collect fractions at 115-125°C to obtain 235.85g of methyl 2,4-dichlorophenoxyacetate with a content of 98...

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Abstract

The invention provides a preparation method of 2,4-dichlorophenoxyacetic ester, wherein the preparation method includes the following steps: S1) carrying out a reaction of phenol and methyl chloroacetate under alkaline conditions to obtain methyl phenoxyacetate; S2) carrying out selective chlorination reaction of methyl phenoxyacetate with a chlorinating agent under the action of a catalyst A anda catalyst B to obtain 2,4-methyl dichlorophenoxyacetate, wherein the catalyst A is Lewis acid, and the catalyst B is C5-22 thioethers, thiazoles, isothiazoles and thiophenes or halogenated derivatives thereof; and S3) carrying out transesterification reaction of 2,4-methyl dichlorophenoxyacetate and alcohol under the action of a catalyst, to obtain 2,4-dichlorophenoxyacetic ester, wherein the alcohol is C2-20 alcohol. The selective chlorination reaction is carried out with methyl phenoxyacetate as a raw material, the selectivity of the reaction is improved, the loss of effective components isavoided, the yield of the effective components is greatly improved, and the three-waste treatment capacity, the three-waste treatment difficulty and the treatment cost are reduced.

Description

technical field [0001] The invention relates to the technical field of herbicide preparation, in particular to a preparation method of 2,4-dichlorophenoxyacetate. Background technique [0002] Phenoxycarboxylate herbicides are the first type of hormone-type selective herbicides commercially produced in the world. They are environmentally friendly, have the characteristics of short residual period and low toxicity to humans and other organisms, and rarely produce drug resistance. It is mainly used for the control and control of dicotyledonous weeds, sedges and some malignant weeds in grass crop fields such as corn and wheat. The most widely used phenoxycarboxylate herbicides are the chlorophenoxyacetate series. Among them, 2,4-dichlorophenoxyacetate is the most widely used. [0003] At present, the preparation method of 2,4-dichlorophenoxyacetate mainly comprises the following two steps: [0004] 1) Using phenol as the main raw material, 2,4-dichlorophenol is obtained thro...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C69/708C07C67/31C07C67/307C07C67/03
CPCC07C67/03C07C67/307C07C67/31C07C69/708
Inventor 孙国庆侯永生张利国迟志龙胡义山
Owner SHANDONG RUNBO BIOTECH CO LTD