6-Chloropicolinic acid

1929-82-4

4684-94-0

General procedure for the synthesis of 6-chloropyridine-2-carboxylic acid from 2-chloro-6-trichloromethylpyridine: 2-chloro-6-trichloromethylpyridine (115.5 g, 0.5 mol) and 98% concentrated sulfuric acid (60 g, 0.6 mol) were added sequentially to a 500 mL three-neck flask equipped with a thermometer. The reaction mixture was heated to 100 °C and maintained at this temperature for 8 hours. Upon completion of the reaction, the reaction solution was cooled to 60 °C and neutralized by slow dropwise addition of 27% ammonia until the pH reached 7. Subsequently, the reaction mixture was cooled to room temperature with continuous stirring to precipitate the solid. The white solid product was collected by diafiltration in 90% yield with a melting point of 192-193 °C.