Preparation method of 2-chloro-5-trichloromethylpyridine

A technology of trichloromethylpyridine and picoline, which is applied in the field of chemical compounds, can solve the problems of many reaction steps, difficult separation, pollution, etc., and achieve the effects of mild reaction conditions, sufficient vapor-liquid contact, and reduced side reactions

Inactive Publication Date: 2015-04-08
JIANGSU YANGNONG CHEM GROUP
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Patents US4205175, US4241213A, US4497955 and CN100348319 publicly reported the method for preparing 2-chloro-5-trichloromethylpyridine by gas-solid phase chlorination of 3-picoline. The reaction temperature generally requires 250-400°C, and the reaction process is difficult to control. A large number of by-products are produced in the reaction process, and the properties of various products generated by the reaction are similar and difficult to separate, resulting in a low yield of the target product
The patent DE10256999A document describes the method of chlorinating and synthesizing 3-trichloromethylpyridine with trifluoroacetic acid or perfluoropropionic acid and 3-methylpyridine to form adducts, and the selectivity of 3-trichloromethylpyridine can reach 98%, but the selectivity of 2-chloro-5-trichloromethylpyridine obtained by ring chlorination of 3-trichloromethylpyridine is poor, and the raw material price of trifluoroacetic acid is expensive
2-Chloro-5-methylpyridine is an intermediate based on the synthesis of imidacloprid pesticides. There are many steps in the reaction, the cost is high, and it is easy to cause pollution
These reasons all cause the industrialized production implementation of 2-chloro-5-trichloromethylpyridine to be very difficult

Method used

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  • Preparation method of 2-chloro-5-trichloromethylpyridine

Examples

Experimental program
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Effect test

Embodiment 1

[0021] Take 500 g of 3-picoline and dissolve in 2000 g of chloroform, then add 10 g of phosphorus pentachloride and 1 g of azobisisobutyronitrile, stir and mix to form a homogeneous feed solution.

[0022] Feed liquid is injected into the first plate of the microreactor with a speed of 100g / h with a horizontal flow pump, and the reaction temperature is kept at 90°C, and chlorine gas is passed into the second plate of the microreactor at a speed of 2L / min. After the materials are mixed on the mixing plate, they react at a constant temperature, continuously feed and discharge materials, collect the reaction liquid, reflux through nitrogen to drive away chlorine and hydrogen chloride, separate and recover the chlorination transition products and put them in the raw materials to continue the reaction.

[0023] Sampling liquid spectrum analysis, the analysis results were: 9.2% of 3-trichloromethylpyridine, 5.1% of 2-chloro-5-dichloromethylpyridine, 75.20% of 2-chloro-5-trichlorometh...

Embodiment 2

[0026] Take 500 g of 3-picoline and dissolve in 3000 g of carbon tetrachloride, then add 20 g of phosphorus pentachloride and 2 g of azobisisobutyronitrile, stir and mix to form a homogeneous phase. Use a horizontal flow pump to pump the feed liquid into the microreactor at a speed of 250g / h, keep the temperature at 110°C, and pass chlorine gas into the microreactor at a speed of 6L / min. After the materials are mixed on the mixing plate, they will react at a constant temperature and feed continuously. Discharge, collect the reaction liquid, reflux through nitrogen to catch chlorine and hydrogen chloride, then remove the solvent, sample liquid analysis content: 7.5% of 3-trichloromethylpyridine, 4.1% of 2-chloro-5-dichloromethylpyridine, 73.4% of 2-chloro-5-trichloromethylpyridine, 6.5% of 2,6-dichloro-5-trichloromethylpyridine; high-vacuum rectification of desolvation feed liquid to obtain 2-chloro-5-trichloromethylpyridine The yield of pyridine was 72.36%.

Embodiment 3

[0028] Take 500 g of 3-picoline and dissolve in 4000 g of chloroform, then add 20 g of phosphorus pentachloride and 2 g of benzoyl peroxide, stir and mix to form a homogeneous phase. Use a horizontal flow pump to pump the feed liquid into the microreactor at a speed of 300g / h, keep the temperature at 100°C, and pass chlorine gas into the microreactor at a speed of 8L / min. After the materials are mixed on the mixing plate, they will react at a constant temperature and feed continuously. Discharging, collecting the reaction liquid, refluxing the nitrogen gas to catch chlorine and hydrogen chloride, and then removing the solvent, the content of the sample liquid spectrum analysis: 10.2% of 3-trichloromethylpyridine, 4.1% of 2-chloro-5-dichloromethylpyridine, 75.8% of 2-chloro-5-trichloromethylpyridine, 4.8% of 2,6-dichloro-5-trichloromethylpyridine; high vacuum distillation of desolvation feed liquid to obtain 2-chloro-5-trichloromethylpyridine The yield of pyridine was 76.60%. ...

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Abstract

The invention discloses a preparation method of 2-chloro-5-trichloromethylpyridine, and belongs to the technical field of chemical combination. The method comprises the following steps: by adopting 3-methylpyridine as a raw material, under the condition of presence of an organic solvent and an initiator, carrying out one-step liquid-phase chlorination on a chlorine gas and 3-methylpyridine in a micro-reactor, so as to synthesize 2-chloro-5-trichloromethylpyridine; firstly, desolventizing, and separating and purifying by a high-vacuum distillation method; separating and recycling a chlorinated transitional product to further react with the raw material; and purifying, so as to obtain the 2-chloro-5-trichloromethylpyridine product. The preparation method of 2-chloro-5-trichloromethylpyridine is full in gas-liquid contact, large in heat exchange area, and mild in reaction condition; the side reaction can be reduced; and the yield can reach 72%-80%.

Description

technical field [0001] The invention belongs to the technical field of compounding, and in particular relates to a preparation method of 2-chloro-5-trichloromethylpyridine, a medicine and pesticide intermediate. Background technique [0002] 2-Chloro-5-trichloromethylpyridine is a very important pharmaceutical and pesticide intermediate, which can be used to prepare pharmaceuticals, agricultural chemicals and biological agents, especially for the synthesis of high-efficiency new pesticides such as haloxyfop and imidacloprid The crucial intermediate of the first-class chloropyridine-containing new pesticides, the new chloropyridine-containing pesticides synthesized from 2-chloro-5-trichloromethylpyridine are being researched and developed vigorously at home and abroad. [0003] Many researchers at home and abroad have studied the preparation method of 2-chloro-5-trichloromethylpyridine, and the reported ones mainly include 3-methylpyridine, 2-chloro-5-methylpyridine chlorinat...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D213/61
CPCC07D213/61
Inventor 史雪芳丁克鸿田宇张晓谕李杰董俊明
Owner JIANGSU YANGNONG CHEM GROUP
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