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Preparation method of dicamba methyl ester

A technology of dicamba methyl ester and methanol, applied in the field of pesticides, can solve the problems of low purity of dicamba methyl ester, difficult to be widely used, different products, etc., and achieve the effects of improving yield and purity, improving working environment, and improving yield

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

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Problems solved by technology

[0003] Dicamba methyl is an important intermediate in the synthesis process of dicamba. The existing process mainly prepares dicamba methyl from 3,6-dichlorosalicylic acid, which needs to be reacted with sodium hydroxide to form a salt, and methylated reagent Dicamba methyl is obtained by reaction, but the yield in the synthesis process is low, the purity of dicamba methyl is low, and the product phase is poor, so it is difficult to be widely used

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  • Preparation method of dicamba methyl ester

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Effect test

Embodiment 1

[0040] Put 1500kg of 3,6-dichlorosalicylic acid, 2300kg of 32% liquid caustic soda, 3000kg of water, 3200kg of 50% methanol and 50kg of tetrabutylammonium bromide into the beating kettle for beating, put it into the etherification kettle after beating, and heat up to 90- Insulate at 95°C, fill with methyl chloride to carry out etherification reaction for 12 hours, after the reaction is completed, transfer the reaction liquid from the etherification tank to the methanol recovery tank to raise the temperature and distill methanol, the temperature rises to 85°C, keep it warm for 1 hour, after the dealcoholization is completed, the methanol is transferred to the methanol storage tank The tank was reused for etherification reaction, and after dealcoholization, the liquid was left to stand for 60 minutes to separate layers, and the water phase was transferred to multi-effect evaporation for treatment. The oil phase is transferred to the still. Turn on the vacuum pump, pump the negat...

Embodiment 2

[0042] Put 1502kg of 3,6-dichlorosalicylic acid, 2302kg of 32% liquid caustic soda, 3005kg of water, 3202kg of 50% methanol and 50kg of benzyltriethylammonium chloride into the beating kettle for beating, put it into the etherification kettle after beating, and heat up to 90 Insulate at -95°C, fill with methyl chloride and carry out etherification reaction for 11 hours. After the reaction is completed, transfer the reaction liquid from the etherification kettle to the methanol recovery kettle to heat up and distill the methanol. The temperature rises to 90°C and keep the temperature for 1 hour. The storage tank was reused for etherification reaction, and after dealcoholization, the liquid was left to stand for 80 minutes to separate layers, and the water phase was transferred to multi-effect evaporation for treatment. The oil phase is transferred to the rectifying kettle. Turn on the vacuum pump, pump the negative pressure to -0.090Mpa, raise the temperature to 200°C and begin...

Embodiment 3

[0044] Put 1502kg of 3,6-dichlorosalicylic acid, 2303kg of 32% liquid caustic soda, 3005kg of water, 3202kg of 50% methanol and 50kg of tetrabutylammonium chloride into the beating kettle for beating, put into the etherification kettle after beating, and heat up to 90-95 Keep warm at ℃, fill with methyl chloride and carry out etherification reaction for 12 hours. After the reaction is completed, transfer the reaction liquid from the etherification tank to the methanol recovery tank to raise the temperature and distill the methanol. The etherification reaction was used again, and after the dealcoholization, the liquid was left to stand for 80 minutes to separate layers, and the water phase was transferred to multi-effect evaporation for treatment. The oil phase is transferred to a molecular still. Turn on the vacuum pump, pump the negative pressure to -0.090Mpa, raise the temperature to 200°C and begin to produce distillates, heat-preserved distillation, the gas phase is conden...

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Abstract

The invention provides a preparation method of dicamba methyl ester. The 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 in methanol and a quaternary ammonium salt phase transfer catalyst, and methyl 3,6-dichloro-2-methoxybenzoate is obtained; C) methanolis removed by distillation; D) a system after distillation is left to stand for laying, an organic phase is distilled, and dicamba methyl ester is obtained. In the methylation reaction system of 3,6-dichlorosalicylic acid, methanol is used as a solvent, meanwhile, the quaternary ammonium salt phase transfer catalyst is added, and the yield and purity of dicamba methyl ester are greatly improved. Meanwhile, a method for removing methanol by distillation and then obtaining dicamba methyl ester by distillation is adopted, a recrystallization process in a traditional preparation method is replacedwith the distillation process, decolorization is omitted, and the obtained dicamba product is pure white, high in condition and more environmentally friendly.

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 is...

Claims

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Application Information

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IPC IPC(8): C07C51/41C07C65/05C07C67/11C07C67/54C07C69/92
Inventor 孙国庆侯永生胡义山周长涛
Owner SHANDONG RUNBO BIOTECH CO LTD
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