METHOD OF PURIFICATION OF ADIPIC ACID IN WATER Russian patent published in 2002 - IPC

FIELD: chemical technology. SUBSTANCE: invention relates to a method of purification of adipic acid by crystallization or recrystallization in water which is one of the main substances used for synthesis of polyamide 6-6. Adipic acid comprises trace amount of a catalyst and minimal purity of adipic acid is at least 95%. The indicated crystallization or recrystallization is carried out in the presence of a strong protonic acid and/or in the presence of carbon monoxide. The preferable amount of a strong protonic acid is from 1 to 50 mole/1 mole of metal of a catalyst. Carbon monoxide is at least partial component of atmosphere where the solution is placed into the crystallization or recrystallization reactor or it makes the pressure into indicated reactor above atmosphere one. Said crystallization or recrystallization ensures to decrease the trace content of metallic catalysts in adipic acid. EFFECT: improved method of purification. 7 cl, 1 tbl