Method for heating pyridine salt B3 to prompt chlorination reaction

Abstract

The invention relates to a method for heating pyridine salt B3 to prompt a chlorination reaction. The method is characterized in that: an electric heater and a chlorination reaction kettle are connected through a pipeline to form a closed loop; a pipeline connecting the chlorination reaction kettle to the electric heater is connected to an emptying groove through a branch pipeline; the method comprises the following steps: (1) taking dichloromethane as a solvent and sufficiently dissolving a 3-methoxy-2-methyl-4-pyridone dry product in an amination work section, so as to obtain a solution; dropwise adding phosphorus oxychloride into the solution; (2) injecting heat-conducting oil into a heat-conducting oil heating system, and keeping oil pressure at 0.2-0.4 MPa and oil temperature at 90 DEG C in order to ensure that an oil path passes the chlorination reaction kettle smoothly; heating the chlorination reaction kettle to 80-85 DEG C and refluxing and carrying out heat insulation to react for 8 hours; and (3) recycling excessive dichloromethane in a temperature raising and heat insulation process, and conveying a generated product into a decompression and recycling working section. The method provided by the invention has the advantages that the heat-conducting oil is stable in property and can effectively avoid sudden explosion accidents; a complete reaction can be ensured and the reaction yield is maximized; and the energy loss rate is low, scale is not formed after equipment is used for a long period and the heat exchange efficiency is higher.

Description

technical field [0001] The invention belongs to the technical field of raw material medicine pyridinium salt production, and relates to a method for heating pyridinium salt B3 for chlorination reaction. Background technique [0002] Pyridinium salt is an important pharmaceutical intermediate of pantoprazole. At present, there are not many domestic manufacturers of pyridinium salt. For the production of pyridine hydrochloride, manufacturers at home and abroad mainly use methyl maltol through methyl esterification, ammoniation, chlorination, oxidation, alcoholization, anhydrideization and salt refining. The production process is: methyl maltol After dimethyl sulfate, esterification, ammonification with ammonia water, then add phosphorus oxychloride for chlorination, then add hydrogen peroxide dropwise for oxidation, add methanol for alcoholization, add acetic anhydride for oxidation, add thionyl chloride to form a salt, and then add anhydrous Finished products that can be ref...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a method for heating pyridinium salt B3 for chlorination reaction in order to solve the problems of poor energy utilization rate, easy fouling of equipment, low heat transfer efficiency and major safety hazards in heat exchange with water. The heat exchange medium in the chlorination reaction section is changed from the original water to heat transfer oil for heat exchange

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