Dissolve 188g(2mol) of 3-aminopyridine in 10% hydrochloric acid: 900g(content 10%, 2.46mol), completely dissolve and mix the solution with dichloromethane: 400g, sodium hypochlorite solution: The volume ratio of 800g(content 10%, 1.07mol) of the three is used as the preset unit time volume ratio, and then according to the unit time volume ratio, the three are respectively and continuously pumped into the first stage extraction centrifuge for extraction centrifuge at normal temperature (the specific temperature range of the normal temperature is 10ºC-30ºC). After that, the organic phase and the aqueous phase are separated, and the organic phase is retained. The aqueous phase, industrial hydrochloric acid: 59g(content 31%, 0.5mol), dichloromethane: 200g, and sodium hypochlorite solution are combined: 400g(content 10%, 0.54mol) volume ratio of four components Chemicalbook was used as the preset unit time volume ratio, and then according to the unit time volume ratio, the four components were separately and continuously pumped into the second stage extraction centrifuge for extraction centrifuge at room temperature. After that, the organic phase and the water phase are separated, and the organic phase is retained, and the water phase is put into the next stage of extraction centrifuge; Subsequently, the amount of hydrochloric acid, dichlorothane and sodium hypochlorite solution used in each stage of extraction centrifuge was halved step by step, a total of five stages of continuous extraction reaction (each stage of extraction centrifuge reaction time was 3h), and then the combined organic phase was 3-amino-2-chloropyridine solution. A total of 962g solution was obtained. The content of 3-amino-2-chloropyridine was 24.4%, the weight of 3-amino-2-chloropyridine was 234.5g, the molar yield of 3-amino-2-chloropyridine was 91.3% (measured by 3-aminopyridine), and the purity was 98.4%.
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