Preparation method of dicamba

A technology for dicamba and catalyst, applied in the field of preparation of dicamba, can solve the problems of low conversion rate of salicylic acid, low reaction yield and purity, product difference, etc., achieves stable and efficient separation of impurities, shortens production process, and is easy to use. The effect of industrialization

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] At present, the mainstream synthesis route of dicamba is to use 3,6-dichlorosalicylic acid as the raw material, and undergo processes such as beating, etherification, alkaline hydrolysis, decolorization, acidification, pressure filtration, recrystallization, centrifugation and drying to obtain dicamba , the conversion rate of salicylic acid in this route is low, resulting in low reaction yield and purity, and the product is yellow or light yellow, with poor product phase and easy to agglomerate. In order to improve product quality, a step of activated carbon decolorization is also added. The dust is large, the workers' work site is not controlled, the recrystallization, centrifugation and drying processes have a strong smell, and the pressure on environmental protection is high, which makes it difficult to industrialize production

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] Get 52.30 grams of 99% 3,6-dichlorosalicylic acid, transfer it to an etherification kettle after beating, add CAT-1 to a total of 0.1 grams, and detect that the salicylic acid has not been converted to 0.02% after etherification, and the etherification liquid is divided into layer, the oil phase was distilled under high vacuum to obtain dicamba methyl ester with a purity of more than 99.5%, transferred to an acidolysis kettle, added 120 grams of 40% sulfuric acid, cooled after acidolysis, filtered, washed, and dried to obtain 54.67 grams of dicamba , the content is 98.65%, and the converted yield is 97.57%. The appearance of the product is white particles.

Embodiment 2

[0042] Get 52.30 grams of 99% 3,6-dichlorosalicylic acid, transfer it to an etherification kettle after beating, add CAT-2 to a total of 0.1 grams, and detect that the salicylic acid has not been converted to 0.01% after etherification, and the etherification liquid is divided into layer, the oil phase was distilled under high vacuum to obtain dicamba methyl ester with a purity of more than 99.5%, transferred to an acidolysis kettle, added 120 grams of 40% sulfuric acid, cooled after acidolysis, filtered, washed, and dried to obtain 54.14 grams of dicamba , content 99.12%, conversion yield 97.09%. The appearance of the product is white particles.

Embodiment 3

[0044] Get 52.30 grams of 99% 3,6-dichlorosalicylic acid, transfer it to an etherification kettle after beating, add CAT-3 to a total of 0.1 grams, and detect that the salicylic acid has not been converted to 0.02% after etherification, and the etherification liquid is divided into Layer, the water phase is transferred to the waste water treatment process, the oil phase is distilled under high vacuum to obtain dicamba methyl ester with a purity of more than 99.5%, and then transferred to the acid hydrolysis kettle, adding 120 grams of 40% sulfuric acid, cooling down after acid hydrolysis, filtering and washing , drying to obtain 54.86 grams of dicamba, with a content of 98.21%, and a converted yield of 97.48%. The appearance of the product is white particles.

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Abstract

The invention provides a preparation method of dicamba. The preparation method comprises the steps as follows: A) 3,6-dichlorosalicylic acid is salified under an alkaline condition; B) 3,6-dichlorosalicylate and halomethane are subjected to a methylation reaction under the action of a catalyst, and 3,6-dichloro-2-methyl methoxybenzoate is obtained, wherein the catalyst comprises tertiary amine andquaternary ammonium salt; C) methyl 3,6-dichloro-2-methoxybenzoate is subjected to acidification and drying, and dicamba is obtained. A compound phase transfer catalyst is adopted in the etherification process, so that salicylic acid is completely converted into dicamba methyl ester, separation of oil and water phases is realized, alkaline hydrolysis and acidification routes in the prior art arereplaced by distillation and acidification, the production process in the whole process is simple, the product quality is good and industrial production is facilitated.

Description

technical field [0001] The invention relates to the technical field of herbicides, in particular to a preparation method of dicamba. 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 gradually attracted attention. With the continuous development of transgenic crops, dicamba ushers in new opportunities for development. [0003] At present, the mainstream synthesis route of dicam...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C51/09C07C65/21
Inventor 孙国庆侯永生迟志龙胡义山周长涛
Owner SHANDONG RUNBO BIOTECH CO LTD
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