Synthesis method for raw material drugs of dicamba

Abstract

The invention relates to a synthesis method for raw material drugs of dicamba. The synthesis method for the raw material drugs of dicamba comprises the following steps: taking 2,5-dichlorophenol as a starting material, carrying out esterification under the actions of an organic solvent and an organic esterification reagent to generate 2,5-dichlorophenol acetate; dissolving 2,5-dichlorophenol acetate in the organic solvent and adding a catalyst to generate Fries rearrangement, thus generating 3,6-dichloro-2-hydroxyacetophenone; making 3,6-dichloro-2-hydroxyacetophenone react with a methylating reagent under the action of an acid-binding agent to obtain 3,6-dichloro-2-methylacetophenone; synthesizing dicamba (3,6-dichloro-2-methoxybenzoic acid) under the action of 3,6-dichloro-2-methylacetophenone. The synthesis method for the raw material drugs of dicamba disclosed by the invention is simple in process, highly available in raw materials and the catalyst, low in cost, simple in post-treatment operation, low in environmental pollution, high in safety of reaction operation, high in reaction yield, good in product quality and favorable for industrialization.

Description

technical field

[0001] The invention belongs to the technical field of pesticide production, in particular to a method for synthesizing dicamba technical. Background technique

[0002] The dicamba chemical is 3,6-dichloro-2-methoxybenzoic acid, which is a benzoic acid herbicide, and is a high-efficiency and low-toxic dryland herbicide that is encouraged and developed by the state. Dicamba is suitable for weeding in dry land. It has a systemic conduction effect and can be quickly absorbed by broad-leaved grasses after spraying. It has a significant control effect on annual and perennial broad-leaved weeds. Dicamba can be decomposed by microorganisms in the soil. It is relatively safe for wheat, corn, millet, and other gramineous plants. It has the characteristics of strong herbicidal power, rapid drug effect, less dosage, moderate long-lasting effect, and high economic benefits. It is a safe herbicide with high efficiency, low toxicity and good selectivity, which is widely u...

Examples

Embodiment 1

[0021] A method for synthesizing the original drug of dicamba,

[0022] Specific steps are as follows:

[0023] Add 81.5g (0.5mol) of 2,5-dichlorophenol and 200mL of tetrahydrofuran to a four-necked flask equipped with stirring, thermometer, dropping funnel, and reflux condenser (with calcium oxide drying tube), stir well, and add 61.25 g (0.6mol) acetic anhydride, slowly heated to 60-80°C, and reacted for 1.5h. After the reaction is complete, add ice water to cool down, filter, and wash with ice water to obtain a white solid that is 2,5-dichlorophenol acetate. The content is 94.4%, and the yield is 92.8%.

[0024] Add the product from the previous step (2,5-dichlorophenol acetate), 150 mL of nitrobenzene, and anhydrous ferric chloride into the three-necked flask, start stirring, slowly raise the temperature to 120°C, and react for 5 hours. After the reaction, the reaction solution was poured into a beaker filled with ice water and concentrated hydrochloric acid, and stirre...

technical field

[0001] The invention belongs to the technical field of pesticide production, in particular to a method for synthesizing dicamba technical. Background technique

[0002] The dicamba chemical is 3,6-dichloro-2-methoxybenzoic acid, which is a benzoic acid herbicide, and is a high-efficiency and low-toxic dryland herbicide that is encouraged and developed by the state. Dicamba is suitable for weeding in dry land. It has a systemic conduction effect and can be quickly absorbed by broad-leaved grasses after spraying. It has a significant control effect on annual and perennial broad-leaved weeds. Dicamba can be decomposed by microorganisms in the soil. It is relatively safe for wheat, corn, millet, and other gramineous plants. It has the characteristics of strong herbicidal power, rapid drug effect, less dosage, moderate long-lasting effect, and high economic benefits. It is a safe herbicide with high efficiency, low toxicity and good selectivity, which is widely u...

Examples

Embodiment 1

[0021] A method for synthesizing the original drug of dicamba,

[0022] Specific steps are as follows:

[0023] Add 81.5g (0.5mol) of 2,5-dichlorophenol and 200mL of tetrahydrofuran to a four-necked flask equipped with stirring, thermometer, dropping funnel, and reflux condenser (with calcium oxide drying tube), stir well, and add 61.25 g (0.6mol) acetic anhydride, slowly heated to 60-80°C, and reacted for 1.5h. After the reaction is complete, add ice water to cool down, filter, and wash with ice water to obtain a white solid that is 2,5-dichlorophenol acetate. The content is 94.4%, and the yield is 92.8%.

[0024] Add the product from the previous step (2,5-dichlorophenol acetate), 150 mL of nitrobenzene, and anhydrous ferric chloride into the three-necked flask, start stirring, slowly raise the temperature to 120°C, and react for 5 hours. After the reaction, the reaction solution was poured into a beaker filled with ice water and concentrated hydrochloric acid, and stirre...

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