Synthesis methods of 3, 6-dichloro-2-methoxybenzoic acid and its intermediate

A technology of p-toluic acid and synthesis method, which is applied in the directions of oxidative preparation of carboxylic acid, chemical instruments and methods, and ozonation of carboxylic acid to prepare carboxylic acid, etc. question

Inactive Publication Date: 2016-02-03
JIANGSU LIANHE CHEM TECH +1
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The technical problem to be solved by the present invention is to provide a dicamba preparation method in order to overcome the defects of complicated reaction steps, low conversion rate, low yield, high production cost, serious environmental pollution, and unsuitability for industrialized production in the prior art. A kind of 3, the synthetic method of 6-dichloro-2-methoxybenzoic acid and its intermediate

Method used

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  • Synthesis methods of 3, 6-dichloro-2-methoxybenzoic acid and its intermediate
  • Synthesis methods of 3, 6-dichloro-2-methoxybenzoic acid and its intermediate
  • Synthesis methods of 3, 6-dichloro-2-methoxybenzoic acid and its intermediate

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Experimental program
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Effect test

Embodiment 12

[0081] Embodiment 12,3, the preparation of 5-trichloro-p-methylbenzoic acid

[0082] Add 68g of p-toluic acid (HPLC purity 99%) to 200g of methanesulfonic acid, add 0.81g of ferric chloride, heat to 80°C and stir, and slowly feed 106.5g of chlorine gas under normal pressure (101325Pa). Reacted for 10 hours, the liquid phase (HPLC) detected that the area content of 2,3,5-trichloro-p-methylbenzoic acid was about 50%, and then cooled to room temperature, and the white crystals separated out by suction filtration were washed with a small amount of methanesulfonic acid, and 50 g of acetic acid was added Recrystallize, filter after cooling, mainly monochlorine product and dichloroproduct in the mother liquor, apply mechanically to next batch of chlorination reaction, filter cake is 2,3,5-trichloro-p-methylbenzoic acid 64.7g, HPLC purity is 93%, yield 54%, yield 85% after applying mechanically.

Embodiment 22

[0083] Embodiment 22,3, the preparation of 5-trichloro-p-methylbenzoic acid

[0084] Add 68g of p-toluic acid (HPLC purity 99%) to 200g of methanesulfonic acid, add 0.81g of ferric chloride, heat to 120°C and stir, and slowly feed 106.5g of chlorine gas under normal pressure (101325Pa). Reacted for 6 hours, the liquid phase (HPLC) detected that the area content of 2,3,5-trichloro-p-methylbenzoic acid was about 50%, and then cooled to room temperature, and the white crystals separated out by suction filtration were washed with a small amount of methanesulfonic acid, and 50 g of acetic acid was added Recrystallization, filter after cooling, mainly monochlorine product and dichloroproduct in the mother liquor, apply mechanically to next batch of chlorination reaction, filter cake is 2,3,57.5g of 5-trichloro-p-toluic acid, HPLC purity is 91%, 48% yield, 80% yield after applying mechanically.

Embodiment 32

[0085] Embodiment 32,3, the preparation of 5-trichloro-p-methylbenzoic acid

[0086] Add 68g of p-toluic acid (HPLC purity 99%) to 200g of methanesulfonic acid, add 0.81g of ferric chloride, heat to 50°C and stir, and slowly feed 106.5g of chlorine gas under normal pressure (101325Pa). After 24 hours of reaction, the area content of 2,3,5-trichloro-p-toluic acid was detected by liquid phase (HPLC) to be about 50%, and then it was lowered to room temperature, and the white crystals separated out were filtered by suction, washed with a small amount of methanesulfonic acid, and 50 g of acetic acid was added to Crystallized, filtered after cooling, mainly monochlorine product and dichlorine product in the mother liquor, applied mechanically to the next batch of chlorination reaction, the filter cake was 69.4g of 2,3,5-trichloro-p-methylbenzoic acid, and the HPLC purity was 94 %, the yield is 58%, and the yield is 87% after applying mechanically.

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Abstract

The invention discloses synthesis methods of 3, 6-dichloro-2-methoxybenzoic acid and its intermediate. The invention provides the synthesis method of 2, 3, 6-trichlorobenzoic acid. The synthesis method comprises that in the presence of a catalyst, 2, 3, 6-benzotrichloride and an oxidation reagent undergo an oxidation reaction to produce 2, 3, 6-trichlorobenzoic acid. The synthesis methods have simple processes, a high conversion rate, a high yield, high product purity, a low production cost and environmental friendliness and are suitable for industrial production.

Description

technical field [0001] The invention relates to a synthesis method of 3,6-dichloro-2-methoxybenzoic acid and its intermediate. Background technique [0002] Dicamba, also known as Baicao, has a chemical name of 3,6-dichloro-2-methoxybenzoic acid. Belonging to benzoic acid herbicides, it has the characteristics of high efficiency, broad spectrum, low toxicity, etc., strong herbicide, less dosage and low cost. It is mainly used to control annual or perennial broad-leaved weeds in the field of grasses such as wheat, such as pig scorpion, buckwheat vine, succulent, quinoa, cow chickweed, cocklebur, shepherd's purse, field bindweed, etc. Hundreds of species . Dicamba has a systemic conduction effect and is used for post-emergence spraying. Usually, weeds will appear deformed and curly within 24 hours of application, and die within 15-20 days. Grass crops such as wheat, corn, rice, and millet can quickly metabolize and decompose after absorbing the drug, showing strong drug res...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C51/265C07C63/70C07C51/27C07C51/16C07C51/285C07C51/305C07C51/34C07C51/41C07C51/367C07C65/21
CPCC07C51/265C07C51/16C07C51/27C07C51/285C07C51/305C07C51/34C07C51/367C07C51/412
Inventor 樊小彬林行军周述勇贾磊沈启富
Owner JIANGSU LIANHE CHEM TECH
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