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Preparation method of 2,3-dichlorin-5-trifluoro picoline

A technology of trifluoromethyl pyridine and methyl pyridine is applied in the field of preparation of pesticide intermediate 2-chloro-3-trifluoromethyl pyridine, and can solve the problems of difficult separation of tar, low product purity, difficult equipment to solve and the like , to achieve the effect of low production cost, high purity and easy operation

Inactive Publication Date: 2007-10-31
山东广恒化工有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Only 40% of the product is produced, with many by-products and tar, which is difficult to separate, and the product has a low purity of only 95%, which is difficult to solve by other equipment

Method used

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  • Preparation method of 2,3-dichlorin-5-trifluoro picoline

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] (1) Chlorination

[0030] Into a 1000L chlorination kettle, pump 200kg of dried raw materials 2-chloro-3-picoline, 6kg of phosphorus trichloride, 1000kg of carbon tetrachloride, and 5kg of azobisisobutyronitrile. Turn on the light source (two 800W ultraviolet lights), heat up the jacket with steam, open the tail gas system, and operate with a slight negative pressure (-0.02MPa). When the temperature in the kettle reaches 80°C, start to pass chlorine, and the chlorine flow rate is 45kg / h, first fast and then slow, keep the reflux reaction, through sampling analysis, G.C detects that the content of trichloride reaches more than 90% and the content of dichlorine is less than 5% is the end of the reaction. If you need to continue the reaction, take a sample and analyze it every 2 hours until it is qualified. .

[0031] After passing the test, stop the chlorine flow, pump the reaction solution into the carbon tetrachloride distillation kettle, and steam the carbon tetrachl...

Embodiment 2

[0038] With the technological operation step of embodiment 1. The different conditions are:

[0039] The catalyzer that the chlorination reaction stage adopts is benzoyl peroxide meter 15kg. Organic solvent adopts dichloromethane 1200kg.

[0040] The catalyst antimony pentachloride is used in the fluorination reaction stage, the addition amount is 1kg, the reaction temperature is 170-180°C, the pressure is 7MPa, and the reaction time is 24 hours.

[0041] The product purity is above 98%, and the yield is 85%.

Embodiment 3

[0043] With the technological operation step of embodiment 1. The different conditions are:

[0044] The catalyst used in the chlorination reaction stage is 7kg of tungsten hexachloride and 3kg of phosphorus trichloride. Organic solvent adopts dichloronitrobenzene 2000kg.

[0045] In the fluorination reaction stage, the catalyst antimony pentafluoride is used, the addition amount is 0.7kg, the reaction temperature is 170-180°C, the pressure is 8MPa, and the reaction time is 26 hours.

[0046] The product purity is above 98%, and the yield is 86%.

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Abstract

The invention discloses a preparing method of 2-chlorine-3-trifluoro metyl group pyridine as new type pesticide intermediate, which comprises the following steps: refluxing organic solvent; chlorinating 2-chlorine-3-metyl group pyridine; stripping organic solvent; crystallizing; centrifuging; hot-dissolving chlorinated material; fluoriding; distilling steam; separating; rectifying. This invention possesses simple craft and easy to operate, which can get high purity product with purity not less than 98% and receiving ratio at about 85%.

Description

technical field [0001] The invention relates to a preparation method of a pesticide intermediate 2-chloro-3-trifluoromethylpyridine. Background technique [0002] 2-Chloro-3-trifluoromethylpyridine is a key intermediate in the synthesis of pyrazosulfuron-methyl, a selective post-emergence herbicide used to control barnyard weeds, such as cotton, soybean, rapeseed, etc. In large fields, the effect of controlling annual and perennial weeds is remarkable. It has the characteristics of good migration in plants, efficacy and efficacy can reach untouched underground parts, less dosage per mu, low toxicity and low residue. [0003] 2-Chloro-3-trifluoromethylpyridine is a new type of pesticide intermediate, which is also widely used in organic synthesis, dyes, and medicine. In recent years, it has been found that the introduction of trifluoromethyl on the heterocycle can improve the affinity of the compound. Lipidity, thereby improving the permeability to biological membranes and ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D213/61
Inventor 王彬
Owner 山东广恒化工有限公司
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