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Preparation method of micamba methyl ester

A technology of dicamba methyl and methanol, which is applied in the field of pesticides, can solve the problems of complex synthesis process, low purity of dicamba methyl, and high equipment requirements, and achieve the effects of high reaction selectivity, fast reaction rate and high purity

Inactive Publication Date: 2019-05-17
SHANDONG RUNBO BIOTECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Dicamba methyl ester is an important intermediate in the synthesis process of dicamba. The existing technology mainly uses 2,5-dichloroaniline as the starting material to synthesize 2,5-dichlorophenol through diazotization-hydrolysis reaction, and then through Carboxylation reaction synthesizes 3,6-dichlorosalicylic acid, and finally dicamba methyl is prepared by methylation reaction, but the synthesis process is complicated, the equipment requirements are high, the cost is high, the yield is low, and the dicamba methyl is relatively pure. Low, poor quality, difficult to be widely used

Method used

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  • Preparation method of micamba methyl ester

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0078] Put 138g of salicylic acid into 1000g of 95% sulfuric acid at 5°C, slowly add 80g of bromine dropwise, raise the temperature to 20°C for 2 hours after the dropwise addition, then raise the temperature to 45°C, and start to introduce chlorine gas, all of which will generate 5-bromo- For 3-chlorosalicylic acid, stop the chlorine flow, slowly add 400g of sulfur trioxide, add 0.15g of iodine, maintain the temperature at 35°C, start to pass in chlorine gas, all of which will generate 5-bromo-3,6-dichlorosalicylic acid in the central control When it is acidic, stop feeding chlorine gas. The reaction solution was poured into ice water, the sulfuric acid concentration of the system was diluted to 30%, filtered, washed with water and dried to obtain 237.8g of 5-bromo-3,6-dichlorosalicylic acid with a yield of 75.0% and a purity of 90.2% (based on salicylic acid acid meter).

[0079] For debromination reaction, add 5-bromo-3,6-dichlorosalicylic acid into 1075g of 10% liquid caus...

Embodiment 2

[0082] Put 138g of salicylic acid into 1000g of 95% sulfuric acid at 5°C, slowly pass in 80g of hydrogen bromide, raise the temperature to 20°C for 2 hours after the dropwise addition, then raise the temperature to 45°C, start to pass in chlorine gas, all of which will generate 5-bromo When -3-chlorosalicylic acid, stop chlorine, slowly add 400g of sulfur trioxide, add 0.15g of iodine, maintain the temperature at 35°C, start to pass in chlorine gas, all 5-bromo-3,6-dichloro water will be generated in the central control When salicylic acid is used, stop feeding chlorine gas. The reaction solution was poured into ice water, the sulfuric acid concentration in the system was diluted to 30%, filtered, washed with water and dried to obtain 238.1 g of 5-bromo-3,6-dichlorosalicylic acid. Yield 75.3%, purity 90.1%.

[0083] For debromination reaction, add 5-bromo-3,6-dichlorosalicylic acid into 1075g of 10% ammonia water, raise the temperature to 40°C until it is fully dissolved, aft...

Embodiment 3

[0086] Put 138g of salicylic acid into 1000g of 95% sulfuric acid at 5°C, slowly pass in 80g of hydrogen bromide, raise the temperature to 20°C for 2 hours after the dropwise addition, then raise the temperature to 45°C, start to pass in chlorine gas, all of which will generate 5-bromo When -3-chlorosalicylic acid, stop chlorine, slowly add 400g of sulfur trioxide, add 0.15g of iodine, maintain the temperature at 35°C, start to pass in chlorine gas, all 5-bromo-3,6-dichloro water will be generated in the central control When salicylic acid is used, stop feeding chlorine gas. The reaction solution was poured into ice water, the sulfuric acid concentration in the system was diluted to 30%, filtered, washed with water and dried to obtain 238.1 g of 5-bromo-3,6-dichlorosalicylic acid. Yield 75.2%, purity 90.2%.

[0087] For debromination reaction, add 5-bromo-3,6-dichlorosalicylic acid into 1075g of 10% potassium hydroxide, raise the temperature to 30°C until it is fully dissolve...

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Abstract

The invention provides a preparation method of micamba methyl ester. The preparation method comprises the steps as follows: A) salicylic acid and bromine are subjected to a reaction in concentrated sulfuric acid, 5-bromosalicylic acid is obtained; B) 5-bromosalicylic acid and chlorine are subjected to a chlorination reaction, 5-bromo-3,6-dichlorosalycylic acid is obtained; C) 5-bromo-3,6-dichlorosalycylic acid is subjected to a debromination reaction under the alkaline condition and under the action of metal powder, and 3,6-dichlorosalycylate is obtained; D) 3,6-dichlorosalycylate and halomethane are subjected to a methylation reaction in methanol and a quaternary ammonium salt phase transfer catalyst, and 3,6-dichloro-2-methyl methoxybenzoate is obtained; E) methanol is removed by distillation; F) a system after distillation is left to stand for laying, an organic phase is distilled, and dicamba methyl ester is obtained. By means of the preparation method, the yield and purity are higher, the route is simple and the production cost is low.

Description

technical field [0001] The invention relates to the technical field of pesticides, in particular to a preparation method of dicamba methyl. Background technique [0002] Dicamba (dicamba), also known as Baicao, has a chemical name of 3,6-dichloro-2-methoxybenzoic acid, a herbicide of the benzoic acid family, and is a low-toxicity, high-efficiency, broad-spectrum herbicide , It has a significant control effect on annual and perennial broad-leaved weeds, but it is relatively safe on grass crops such as wheat, corn, millet, and rice. With the prohibition and restriction of metsulfuron-methyl and chlorsulfuron-methyl preparations, the safety, human health and super weed problems caused by glyphosate have become increasingly prominent. As a traditional high-efficiency herbicide, dicamba has attracted attention and is resistant to dicamba With the continuous development of genetically modified crops, dicamba ushers in new opportunities for development. [0003] Dicamba methyl es...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C67/11C07C67/31C07C67/54C07C69/92
Inventor 孙国庆侯永生胡义山周长涛
Owner SHANDONG RUNBO BIOTECH CO LTD
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