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Synthesis methods of 2-chloro-5-trichloromethylpyridine and 2-chloro-5-trifluoromethylpyridine

A technology of trichloromethylpyridine and trifluoromethylpyridine is applied in the synthesis field of preparing 2-chloro-5-trichloromethylpyridine and 2-chloro-5 trifluoromethylpyridine, and can solve the problem of high cost of raw materials , difficult to separate, poor selectivity and other problems, to achieve the effect of high degree of chlorination, easy separation, less by-products

Inactive Publication Date: 2015-05-13
大连科铎环境科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Among them, 2-chloro-5-trichloromethylpyridine is an important pesticide and pharmaceutical intermediate, which plays a key role in the synthesis of 2,3-dichloro-5-trifluoromethylpyridine, a key intermediate of high-efficiency Gai Caoneng. Significance, it can also be used as an important intermediate for the synthesis of pesticides difenthuron and imidazoturon, and has a broad market prospect. 2-Chloro-5-trifluoromethylpyridine is the key to the synthesis of fluazifop-methyl (Wenzat) Intermediate, 2-chloro-5-trichloromethylpyridine There are generally two methods reported in the literature, one is to obtain the final product by chlorination of 2-chloro-5-chloromethylpyridine as a raw material, the selectivity is better, However, the cost of raw materials is relatively high. One uses cheap 3-picoline as a raw material, and one-step direct chlorination produces products, but the selectivity is poor, and there are many by-products with different chlorination degrees, which are not easy to separate

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] Embodiment 1: take picoline as raw material to prepare 3-trichloromethylpyridine

[0028] Weigh 367.90g (3.23mol 3.0eq) of trichloroacetic acid and 0.01eq of cobalt chloride into a 500ml three-necked flask, control the temperature at about 40°C, add 100g (1.07mol 1.0eq) of 3-picoline dropwise, and raise the temperature to 60°C after dropping Start to feed chlorine gas with a flow rate of 200ml / min, and turn on the ultraviolet lamp to irradiate the reaction bottle until the raw materials are completely reacted, neutralize the reaction solution with trichloroacetic acid equivalent sodium hydroxide to neutrality, and extract the reaction solution with dichloromethane , GC normalized 3-trichloromethylpyridine 89.5%, 3-dichloromethylpyridine 10%, 3-chloromethylpyridine 0.5%, obtained product 163.9g after rectification and purification, and the separation yield was 78%. The total yield of the fully reacted intermediate can reach 95% after being recovered and continued to chlo...

Embodiment 2

[0029] Embodiment 2: Taking 3-trichloromethylpyridine as raw material to prepare 2-chloro-5-trichloromethylpyridine

[0030] Mix 7.5g of 3-trichloromethylpyridine and 70g of carbon tetrachloride, the volume after mixing is about 50ml, put it into the vaporization chamber at 200°C with a syringe pump for about two hours, and feed chlorine gas at 20ml / min at the same time, the gasified material Enter the 380°C tubular reactor with chlorine gas. There is ferric chloride catalyst immobilized by activated carbon in the reactor. After the reaction, the material is condensed in the receiving bottle, and GC normalizes 90% , the main impurities are raw materials, product isomers, and excessive chlorination products, and the product yield of purity > 99% is obtained through rectification and purification: 85%.

Embodiment 3

[0031] Embodiment 3: Prepare 2-chloro-5-trifluoromethylpyridine with 3-trifluoromethylpyridine as raw material

[0032] Mix 7.8g of 3-trichloromethylpyridine with 100g of carbon tetrachloride, the volume after mixing is about 70ml, put it into the gasification chamber at 200°C with a syringe pump for about two hours, and feed chlorine gas at 20ml / min at the same time, the gasified material Enter the 420°C tubular reactor with chlorine gas. There is ferric chloride catalyst immobilized by activated carbon in the reactor. After the reaction, the material is condensed in the receiving bottle, and GC normalizes 91% of 2-chloro-5-trifluoromethylpyridine , the main impurities are raw materials, product isomers, and excessive chlorination products, and the product yield of purity > 99% is obtained through rectification and purification: 89%.

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Abstract

The invention discloses synthesis methods of 2-chloro-5-trichloromethylpyridine and 2-chloro-5-trifluoromethylpyridine, namely a novel method, which comprises the steps of carrying out photocatalytic chlorination on trimethylpyridine as a raw material so as to obtain 3-trichloromethylpyridine, and then, carrying out gas-phase thermocatalytic chlorination so as to obtain 2-chloro-5-trichloromethylpyridine, and a method, which comprises the step of carrying out gas-phase thermal chlorination on 3-trifluoromethylpyridine as a raw material so as to obtain 2-chloro-5-trifluoromethylpyridine. The synthesis methods disclosed by the invention have the advantages that the process is simple and easy, the raw materials are cheap and are easily obtained, the yield is relatively high, the purity of products is high, and the like.

Description

technical field [0001] The invention belongs to the field of chemical synthesis, and in particular relates to a synthesis method for preparing 2-chloro-5-trichloromethylpyridine and 2-chloro-5-trifluoromethylpyridine through chlorination of picoline. Background technique [0002] Chlorinated pyridinium and fluorinated pyridinium compounds are important intermediates of various pesticides, fungicides and herbicides in agricultural production. The pesticides and herbicides produced by using these compounds as intermediates have strong selectivity , High indicators and other advantages, so that it has an extremely wide range of uses. Among them, 2-chloro-5-trichloromethylpyridine is an important pesticide and pharmaceutical intermediate, which plays a key role in the synthesis of 2,3-dichloro-5-trifluoromethylpyridine, a key intermediate of high-efficiency Gai Caoneng. Significance, it can also be used as an important intermediate for the synthesis of pesticides difenthuron a...

Claims

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Application Information

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IPC IPC(8): C07D213/61
CPCC07D213/61
Inventor 江文书李超赵光春鲁凯高崇王乃伟
Owner 大连科铎环境科技有限公司
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