Pyridine → 1-(Pyridin-4-yl)pyridin-1-ium chloride--hydrogen chloride (1/1/1)

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Reaction Conditions

Reaction Steps

In one embodiment of the present invention, a process for producing 4-dimethyl amino pyridine is provided. The process comprises initially charging ethyl acetate and pyridine, one by one, under agitation, and maintaining the pot temperature at 25±5° C. Thionyl chloride is then charged gradually while maintaining the temperature below 35° C. After the addition, the reaction mass is refluxed for 4 hours at 77-80° C. After refluxing, the ethyl acetate and unreacted thionyl chloride are distilled off at atmospheric pressure. Finally, mild vacuum (400 to 600 mm Hg) is applied to ensure maximum recovery of ethyl acetate and thionyl chloride. Left over reaction mass is cooled to 40° C. Then anhydrous ethyl alcohol is added slowly while maintaining the temperature below 60° C. The resulting reaction mass is stirred well, then cooled up to 10° C. and then filtered, washed with anhydrous ethyl alcohol and dried under vacuum to get the desired salt N-[4-pyridyl] pyridinium chloride hydrochloride. Mother liquor obtained after filtration is first atmospherically distilled to recover ethyl alcohol and then hydrolysed with caustic lye solution, followed by extraction with benzene and then fractional distillation to recover benzene and pyridine, which can be recycled back into the process.

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