Synthesis
500L reactor add 2-chloropyridine 30 kg, 200 kg of tap water, sodium tungstate 1.5 kg, 2 kg of concentrated sulfuric acid, stirring to dissolve clear; temperature to 55 , slowly drop 30% hydrogen peroxide 100 kg; drop after the completion of the temperature to continue to react for 48 hours, HPLC test raw material conversion rate of 84%, cooled down to room temperature, add 12.3 kg of liquid alkali adjusted to neutral. Add toluene 50 kg, extract the raw material is not fully reacted (the layer can be concentrated to recover toluene and raw materials); aqueous layer to add 20 kg of sodium hydroxide, reflux reaction for 8 hours, HPLC monitoring, showing that the raw material is fully converted, cooled down to 25 C, add hydrochloric acid to adjust the PH = 6, add ethyl acetate extraction, each time the dosage of 30 kg, extract three times, the combined organic phase, with anhydrous sodium sulfate 15 kg drying ; filter, concentrate the organic phase to 1/5 of the original volume, add 85 kg of 60-90 C petroleum ether, cooled to -5 C, stirring crystallization; filtration, drying, to obtain a light yellow crystal powder 22.9 kg, yield: 78.05% (calculated as 2-chloropyridine, and did not calculate the recovery of 2-chloropyridine).
