Preparation process of herbicide dicamba

A preparation process, dicamba technology, applied in the direction of herbicides, algicides, biocides, biocides, etc., can solve the problems of high energy consumption, long reaction time, low yield, etc., to reduce the reaction temperature, reaction The effect of long time and increased productivity

Inactive Publication Date: 2011-07-20
上海力智生化科技有限公司
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  • Summary
  • Abstract
  • Description
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  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantage of this process route is that the reaction time is long, the energy consumption is high and the productive rate is not high

Method used

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  • Preparation process of herbicide dicamba

Examples

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Effect test

Embodiment 1

[0021] Synthesis of Sodium 2,5-Dichlorophenate

[0022] Add 150ml of anhydrous methanol and 27.0g (0.5mol) of sodium methoxide into a 500ml reaction flask. Add dropwise a solution of 81.5g (0.5mol) 2,5-dichlorophenol and 100ml of anhydrous methanol under stirring, drop it in about 15 minutes, and then continue the reaction for 1~2h. After removing the solvent and drying, 2,5-dichlorophenol sodium was obtained almost quantitatively.

[0023] Synthesis of 3,6-dichlorosalicylic acid

[0024] Add 92.5g (0.5mol) dry and finely ground sodium 2,5-dichlorophenolate and 110.5g (0.8mol) powdered anhydrous potassium carbonate to a 500 ml autoclave. After introducing an appropriate amount of carbon dioxide, start heating and stirring, control the temperature in the kettle to 120° C., and then slowly introduce carbon dioxide until the pressure is 8.0 MPa. Along with the progress of the reaction, carbon dioxide was slowly supplemented to ensure that the temperature and pressure in the ke...

Embodiment 2

[0028] Synthesis of Sodium 2,5-Dichlorophenate

[0029] Add 200ml of absolute ethanol and 35.7g (0.52mol) sodium ethoxide to a 500ml reaction bottle, stir and dissolve, then add dropwise a solution of 81.5g (0.5mol) 2,5-dichlorophenol and 100ml of absolute ethanol for about 15 minutes Continue to react for 1~2h after completion. After removing the solvent ethanol and drying, nearly quantitative 2,5-dichlorophenol sodium was obtained.

[0030] Synthesis of 3,6-dichlorosalicylic acid

[0031] Add 92.5g (0.5mol) dry and finely ground sodium 2,5-dichlorophenolate and 96.7g (0.7mol) finely ground anhydrous potassium carbonate to a 500 ml autoclave. After the appropriate amount of carbon dioxide was introduced. Start heating and stirring. After the temperature reaches 130°C, slowly feed carbon dioxide to a pressure of 7.5MPa. As the reaction progresses, continuously replenish carbon dioxide to keep the temperature and pressure in the kettle at 130°C and 7.5MPa. In this supercriti...

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Abstract

The invention relates to a preparation process of herbicide dicamba, in particular to a supercritical preparation process. The preparation process of the herbicide dicamba comprises the following steps of: preparing 2,5-dichlorophenol into corresponding sodium phenolate, and then completing carboxylation reaction under a supercritical condition to obtain 3,6-dichlorosalicylic acid; and then completing O-methylation to prepare a product of 3,6-dichloro-2-methoxy salicylic acid, i.e. the dicamba, by taking dimethyl carbonate as a reagent. The invention changes the heterogeneous gas-solid reaction of the traditional process into homogeneous reaction under the supercritical condition, carries out the O-methylation reaction by using the dimethyl carbonate and has the advantages of high reaction yield, good product quality, reduced environmental pollution, lowered energy consumption, and the like.

Description

technical field [0001] The invention relates to a preparation process of herbicide dicamba. Background technique [0002] Dicamba, also known as banvel, is a benzoic acid herbicide. It is a low-toxicity, high-efficiency, broad-spectrum herbicide and has been widely used. It has the characteristics of strong selectivity, less dosage, and lower cost. It is mainly used for controlling annual and perennial broad-leaved weeds in the fields of wheat and other gramineous crops, and the effect is remarkable. Dicamba is used for post-emergence spraying, and the drug can be quickly absorbed by the leaves, stems, and roots of the weed, conduct upward and downward through the phloem and xylem, and mostly concentrate in the meristematic tissue and parts with strong metabolic activities, hindering the normal activity of plant hormones , leading to its death. Usually within 24 hours after using dicamba, broad-leaved weeds will appear deformed curly symptoms, and die within 15-20 days. H...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): A01N37/40A01P13/00
Inventor 刘锡玲洪伟
Owner 上海力智生化科技有限公司
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