2,3,5-Trichloropyridine

Add 60g methanol to 1000mL four-necked flask, put in 100g 2,3,5,6-tetrachloropyridine, 31.7g hydrazine hydrate, warming to 60-65 C, holding reaction about 2 hours, the end of the reaction, lowering the temperature to 0-5 C, stirring for 1 hour, filtration, the solid that is 2,3,5-trichloro 6-hydrazinium hydrate pyridine, drying to get a white solid 101.6g, yield 96%, content 98.5%.

To a 1000 ml four-necked flask was added 100 g of 2,3,5-trichloro 6-hydrazinium hydrate pyridine, 50g content 5% sodium hydroxide aqueous solution, warming to 70 ~ 75 C, dropwise addition of 387.6g content 10% sodium hypochlorite aqueous solution, holding temperature 70 ~ 75 C, the reaction for 1 hour, the end of the reaction, lower the temperature to 5 ~ 10 C, stirring for 1 hour, filtration to obtain 2,3,5-trichloropyridine crude, distillation under reduced pressure to get the product, a light yellow Solid, yield: 95%, content: 98%.