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A method of catalytic oxidation synthesis of herbicide dicamba 2-methoxy-3,6-dichlorosalicylic acid

A technology of dichlorosalicylic acid and catalytic oxidation, applied in chemical instruments and methods, preparation of organic compounds, organic chemistry and other directions, can solve the problems of low conversion rate, low yield and high cost, and achieves simple operation and easy raw materials. obtainable, low-cost effect

Active Publication Date: 2019-10-18
JIANGSU CHANGQING AGROCHEMICAL CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] 3. In patent documents US:3345157, US4232172, US3013054, US4670610, PO185546, GB1464320, GB1221019, Indian IN:15341; Dichlorophenol is used as a raw material or 2,5-dichlorophenol is prepared by 2,5-dichloroaniline and 1,2,4-trichlorobenzene, and then reacted with potassium hydroxide to form potassium phenolate, which is obtained by Kolbe-Schmitt reaction carboxylation 3,6-dichloro-2-hydroxybenzoic acid is widely used due to its low cost and easy-to-obtain raw materials. However, this method needs to be reacted under high pressure and the conversion rate is low, which brings considerable hidden dangers to production safety. , is a process with high energy consumption and high waste
[0010] 4. In the Japanese patent JP4805574 document, 2-methoxy-3,6-dichlorobenzoic acid is obtained by etherification, Claisen rearrangement, etherification, and oxidation using 2,5-dichlorophenol as a raw material. The preparation method is ingenious, but its yield is low, and a large amount of acid-containing wastewater is produced, so the cost is high, and it has not been adopted by industrial production
Oxidation with sodium hypochlorite will produce a large amount of high-salt wastewater

Method used

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  • A method of catalytic oxidation synthesis of herbicide dicamba 2-methoxy-3,6-dichlorosalicylic acid
  • A method of catalytic oxidation synthesis of herbicide dicamba 2-methoxy-3,6-dichlorosalicylic acid
  • A method of catalytic oxidation synthesis of herbicide dicamba 2-methoxy-3,6-dichlorosalicylic acid

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Experimental program
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Embodiment 1

[0026] 1. Preparation of mesoporous carbon-supported silver, zirconium and copper catalysts

[0027] 1. Dissolve 3.38 grams of silver nitrate in 400ml of distilled water to prepare a solution of 0.05mol / L, put it into a 500ml three-neck flask and stir, and slowly add 25% of 2.72 grams of ammonia water at room temperature, precipitation begins, continue to drip The aqueous ammonia solution becomes colorless and transparent; put 10 grams of mesoporous carbon into the reaction bottle, and then add 2.9 grams of 40% formaldehyde solution and 100 ml of a mixed solution of 0.4 mol / L sodium hydroxide dropwise. Stir slowly at room temperature for 10 hours, then filter, and put the filter bottle cake into an oven for drying to obtain a silver-loaded mesoporous carbon catalyst for use.

[0028] 2. Dissolve 3.38 grams of silver nitrate in 400ml of distilled water to prepare a 0.05mol / L solution, put it into a 500ml three-necked flask and stir, and slowly add 25% of 2.72 grams of ammonia w...

Embodiment 2

[0031] Preparation of Dicamba 3,6-Dichloro-2-methoxybenzoate by Catalytic Oxidation

[0032] 1. Add 24 grams of 3,6-dichloro-2-methoxyacetophenone (which can be prepared according to CN 103819327) into a 500ml glass four-necked bottle equipped with mechanical stirring, thermometer, condenser and ventilation tube, and add Load silver, copper, zirconium mesoporous carbon catalyst 0.5g, sodium carbonate aqueous solution 200ml, heat up to reflux, start to pass air 60ml per minute, react for about 8 hours, cool down to room temperature, filter and recover the catalyst, and precipitate yellow oil 17 gram, recrystallized with toluene to obtain 15.5 grams of 3,6-dichloro-2-methoxybenzoic acid with a content of 95.8%, and a total yield of 68%.

[0033] 2. Add 24 grams of 3,6-dichloro-2-methoxyacetophenone into a 500ml glass four-neck flask equipped with mechanical stirring, thermometer, condenser tube and ventilation tube, and add 0.5 grams of silver-loaded active mesoporous carbon cat...

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PUM

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Abstract

The invention relates to a method for synthetizing a herbicide-dicamba (2-methoxy-3,6-dichloro-salicylic acid) through catalytic oxidation. The method is characterized in that the dicamba is obtained through oxidation of air, oxygen or ozone by taking 2-substituent 3,6-banair as a raw material and adopting a composite catalyst. The method disclosed by the invention has the advantages that the operation is simple, the raw material is easy to obtain, the cost is low, the catalyst can be recycled, and the method is more environment-friendly and is more suitable for industrial production.

Description

technical field [0001] The invention relates to a novel method for synthesizing the herbicide dicamba 2-methoxyl-3,6-dichlorosalicylic acid by catalytic oxidation of highly active mesoporous carbon loaded with silver, copper and zirconium. Background technique [0002] Dicamba, also known as Baicao, has a scientific name of 3,6-dichloro-2-methoxybenzoic acid and belongs to the series of benzoic acid herbicides. It is an efficient, broad-spectrum and relatively friendly herbicide to the environment. It has the characteristics of strong selectivity, less dosage, and lower cost. It can not only expand the herbicidal spectrum when mixed with other herbicides, but also reduce the dosage of dicamba and improve the safety of wheat seedlings. It is relatively safe for grass crops such as wheat, corn, millet, and rice. It disappears after being rapidly decomposed by microorganisms in the soil. [0003] In recent years, there are few reports on the synthesis methods of 3,6-dichloro-...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C65/21C07C51/245C07C51/265
Inventor 张振明丁华平赵河王刚
Owner JIANGSU CHANGQING AGROCHEMICAL CO LTD