Chlorination synthesis process of chlorination workshop section in production of pyridinium salt

Abstract

The invention discloses a chlorination synthesis process of a chlorination workshop section in production of a pyridinium salt. The process provided by the invention adopts 1,2-dichloroethane insteadof conventional dichloromethane as a solvent, a dipole moment of the 1,2-dichloroethane is smaller than that of the dichloromethane, and polarity of 4-chloro-3-methoxy-2-methylpyridine is smaller thanthat of 3-methoxy-2-methyl-4-pyridone, so that improvement of a yield of the 4-chloro-3-methoxy-2-methylpyridine is facilitated; water solubility of the 1,2-dichloroethane is smaller than that of thedichloromethane, so that recycling of the dichloroethane is facilitated, and pollution to the environment is reduced; a binary azeotrope formed by the dichloromethane and water has a boiling point of38.1 DEG C and a water content of 1.5%, and a binary azeotrope formed by the1,2-dichloroethane and water has a boiling point of 71.9 DEG C and a water content of 8.1%, so that when distillation is performed, more water can be carried away, and a use amount of a desiccant can be reduced; and a use amount of phosphorus oxychloride is greatly reduced, and the process does not need vacuum recovery and reuse, thereby reducing safety risk of a reaction.

Description

technical field [0001] The invention relates to a chlorination section in the production of raw material drug pyridinium salt, in particular to a novel chlorination reaction synthesis process. Background technique [0002] Pyridinium salt is an important pharmaceutical intermediate of pantoprazole. At present, there are not many domestic manufacturers of pyridinium salt. The independent team of Anhui Jinhe Industrial Co., Ltd. has developed an advanced process synthesis route, using the methyl maltol independently produced by the company as a raw material to produce pyridinium salts, which has a strong cost advantage and is conducive to the development of production and the improvement of the company's market competitiveness. , Improving the economic efficiency of enterprises is of great significance. [0003] This process utilizes the original chlorination reaction mechanism: [0004] + POCl 3 → +PO 2 HCl 2 [0005] The existing process condition is to particip...

AI Technical Summary

Problems solved by technology

[0005] The existing process condition is to participate in the chlorination reaction with phosphorus oxychloride as a chlorination agent, first fully dissolve the dry product of 3-methoxy-2-methyl-4-pyridone with dichloromethane, and then add all five times A large amount of phosphorus oxychloride is reacted to generate 4-chloro-3-methoxyl-2-picoline. Because the amount of phosphorus oxychloride is relatively large, there is a greater potential safety hazard, and dichloromethane is used as a solvent to dissolve The material yield is low, so it is necessary to develop a more advanced synthesis process to solve the existing safety problems and low yields