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Liquid-phase catalytic oxidation quinclorac preparation method

A technology of quinclorac and liquid-phase catalysis, which is applied in the field of preparation of quinclorac by liquid-phase catalytic oxidation, can solve the problems of large amount of waste acid, low product purity, and difficulty in handling, etc., so as to reduce the discharge of waste liquid, The post-treatment process is simplified and the effect of less impurities

Active Publication Date: 2013-12-04
中国中化股份有限公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to develop a method for preparing quinclorac by liquid-phase catalytic oxidation, so as to effectively improve the problems that the amount of waste acid that exists in the current quinclorac synthesis process is large and difficult to handle and the product purity is not high

Method used

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  • Liquid-phase catalytic oxidation quinclorac preparation method

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Effect test

Embodiment 1

[0020] Add the reaction liquid to a titanium autoclave with a volume of 0.5L, feed oxygen to a pressure of 1.0Mpa, and heat the reaction liquid to 150°C and pressure to 1.6Mpa while stirring. The composition of the reaction solution (i.e. the reaction mixture) is 80.0g of 7-chloro-8-methylquinoline chloride and 300.0g of acetic acid, 5.7g of cobalt acetate tetrahydrate, 1.8g of manganese acetate tetrahydrate, 4.9g 40% of hydrogen bromide. After 4.1 hours of reaction, the reaction system no longer consumes oxygen, and the reaction ends. After cooling down to room temperature and discharging, the solid product was separated and dried. Obtain quinclorac dry product 75.0g, content 86.8%.

[0021] Add 200.0 g of absolute ethanol to 75.0 g of quinclorac crude product, stir and heat up to reflux, keep warm for 2 hours, cool to below 10°C, filter, distill the filtrate to recover ethanol for mechanical use, and dry the filter cake to obtain 63.8 g of quinclorac fine product, The con...

Embodiment 2

[0023] The mother liquor after the solid product was separated in Example 1 was removed through the acetic acid solution distilled out under reduced pressure to remove the water contained therein to obtain 264.0 g of acetic acid.

[0024] Add the reaction liquid to a titanium autoclave with a volume of 0.5L, feed oxygen to a pressure of 1.0Mpa, and heat the reaction liquid to 150°C and pressure to 1.6Mpa while stirring. The composition of the reaction solution (i.e. the reaction mixture) is 80.0 g of 7-chloro-8-methylquinoline chloride, 264.0 g of reclaimed acetic acid, 36.0 g of fresh acetic acid, 1.9 g of cobalt acetate tetrahydrate, 1.8 g of Manganese acetate hydrate, 8.9g of 40% hydrogen bromide. After 4.2 hours of reaction, the reaction system no longer consumes oxygen, and the reaction ends. After cooling down to room temperature and discharging, the solid product was separated and dried. Obtain quinclorac dry product 75.5g, content 86.4%.

[0025] Add 200.0g of absol...

Embodiment 3~10

[0027] Reaction conditions, operation steps and mother liquor treatment recovery mode are the same as embodiment 2. Catalyst consumption and experimental results are shown in Table 1 in each embodiment.

[0028] Table 1 Liquid phase catalytic oxidation prepares quinclorac

[0029] Example

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Abstract

The invention discloses a liquid-phase catalytic oxidation novel method in a quinclorac synthesis process. The method comprises the steps that: in presence of a cobalt-manganese-bromine ternary complex catalyst, gas comprising oxygen molecules is delivered into a 7-chloro-8-methylquinoline chloride reaction system with aliphatic carboxylic acid as a solvent; the temperature is increased to 100-255 DEG C, and pressure of the system is maintained at 0.5-3MPa; when a reaction is finished, solid product is separated; ethanol is used for re-crystallization, such that high-content (no lower than 97%) quinclorac is obtained. Mother liquor after separation is subjected to distillation and dehydration, and can be used again. With the preparation method provided by the invention, problems of long oxidation process time, processing difficulty of product waste acid, low product purity, and the like of current oxidation processes can be effectively ameliorated.

Description

technical field [0001] The invention belongs to the field of organic synthesis, and relates to a preparation method of quinclorac, in particular to a method for preparing quinclorac by liquid-phase catalytic oxidation. Background technique [0002] Quinclorac (also known as 3,7-dichloro-8-quinoline carboxylic acid) is a herbicide with significant efficacy in paddy fields. Ceratum genus, Brachiaria genus, Cormina, etc., especially have remarkable effects on barnyard grass, are safe to crops, and the application time is not limited by the growth stage of weeds. [0003] U.S. Patents US4632696 and US4497651 outline the acquisition of carboxyl groups in quinclorac during the synthesis of quinclorac: by reacting 3,7-dichloro-8-chloromethylquinoline with hydroxylamine hydrochloride to generate 3,7-dichloro- 8-cyanoquinoline, and then react in the presence of concentrated sulfuric acid at 50~150°C to obtain quinclorac. In this regard, CN101337929A proposes an improved method, usi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D215/48
Inventor 闫海生尹荃赵瑞强孙钊孙鸿曼任树杰喻滔
Owner 中国中化股份有限公司
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