Method for synthetizing 2-chlorine-5-flumethiazine

A technology of trifluoromethylpyridine and chloromethylpyridine, which is applied in the synthesis field of 2-chloro-5-trifluoromethylpyridine, can solve the problem that reaction intermediates are easy to polymerize and coke, difficult to realize industrialized production, and poor reaction selectivity and other problems, to achieve the effect of low cost, easy separation and high conversion rate

Inactive Publication Date: 2006-05-31
KANGPENG AGRO CHEM JIANGYAN
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AI Technical Summary

Problems solved by technology

Its chlorination reaction takes 2-chloro-5-picoline as raw material, and carries out at a temperature of 80°C to 200°C. Because the raw material of 2-chloro-5-picoline is difficult to obtain, the reaction temperature is relatively high, and the solvent used, Influenced by initiator and distillation purification temperature, the yield of 2-chloro-5-trifluoromethylpyridine product is low, the cost is high, the reaction selectivity is poor, the reaction intermediate is easy to polymerize and coke, and there are many by-products, so it is difficult to realize industrialization Production

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0013] Add 250g (1.54mol) of 2-chloro-5-chloromethylpyridine and 750g of carbon tetrachloride into a 1L reaction flask, turn on the iodine tungsten lamp and heat to 75°C, add 7.5g of phosphorus trichloride, azodiiso Add 1 g of butyronitrile, feed chlorine gas, continue stirring and heating to reflux, and react by bubbling chlorine gas under the reflux state. After the reaction was carried out for 6 hours, sampling and analysis began. When the content of 2-chloro-5-dichloromethylpyridine in the reaction solution was less than 0.5%, the chlorine ventilation valve was closed, the heating was stopped, and the reaction was terminated. Then the reaction system is cooled to 60°C, and the solvent carbon tetrachloride is removed by distillation under normal pressure. The temperature of the kettle does not exceed 160°C, and then it is distilled under reduced pressure under the protection of nitrogen until the vacuum degree reaches 3mmHg, and the temperature of the kettle reaches 160°C. ...

Embodiment 2

[0016] Change the chlorination temperature in Example 1 to 65°C, and keep the others unchanged. After 24 hours of reaction, distill to obtain 2-chloro-5-trichloromethylpyridine 313.7g, analyze 2-chloro-5-dichloromethane Basepyridine 0.51% (GC), 2-chloro-5-trichloromethylpyridine 99.33% (GC); yield: 88.18%.

[0017] The fluorination reaction process is the same as in Example 1.

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PUM

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Abstract

Synthesis of 2-chlorine-5-trifluopyridine is carried out by taking 2-chlorine-5-chloromethyl pyridine as raw material, chlorination reacting at 60<=t<80íÒC with azodiisobutyronitrile, phosphorus trichloride and light radiation of iodo-tungsten light as evocator, carbon tetrachloride as organic solvent and below distilling purification 160íÒC and fluoridation reacting. It can be used for pesticide and medicine. Its advantages include simple raw material, low cost, high conversion efficiency, better reaction selectivity and more output.

Description

technical field [0001] The invention relates to a preparation method of a fluorine-containing and heterocyclic organic intermediate, especially a synthesis method of 2-chloro-5-trifluoromethylpyridine. Background technique [0002] 2-Chloro-5-trifluoromethylpyridine is a fluorine-containing, heterocyclic key organic intermediate, which has a wide range of applications in fine chemical fields such as pesticides and medicines. The literature of Chinese Patent Publication No. CN1342648A describes the synthesis method of 2-chloro-5-trifluoromethylpyridine. The method undergoes chlorination and fluorination steps to synthesize 2-chloro-5-trifluoromethylpyridine. Its chlorination reaction takes 2-chloro-5-picoline as raw material, and carries out at a temperature of 80°C to 200°C. Because the raw material of 2-chloro-5-picoline is difficult to obtain, the reaction temperature is relatively high, and the solvent used, Influenced by initiator and distillation purification temperatu...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D213/61
Inventor 张京
Owner KANGPENG AGRO CHEM JIANGYAN
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