METHOD OF PURIFYING 2-CHLORO-1,4-PHENYLENEDIAMINE Russian patent published in 2019 - IPC C07C209/84 C07C211/51 

FIELD: chemistry.

SUBSTANCE: invention relates to a method for the purification of 2-chloro-1,4-phenylenediamine by recrystallization from a solution of toluene, which is used in a mass ratio to the starting 2-chloro-1,4-phenylenediamine 2.5–3.5:1, dissolution is carried out at a temperature of 60–90 °C, the resulting solution is filtered at a temperature of 60–80 °C, and the filtrate is subjected to crystallization and drying. Crystallization is carried out in two steps; first, the hot filtrate is gradually cooled with stirring to a temperature of 30–35 °C, then the resulting mass with partially precipitated crystals is cooled to a temperature of 5–15 °C.

EFFECT: obtaining a product with a basic substance content of not less than 99½ %, which is stable when stored for at least 3 years.

3 cl, 4 ex