FIELD: industrial organic synthesis. SUBSTANCE: reaction mixture obtained by direct oxidation of cyclohexane into adipic acid by molecular oxygen in organic solvent and in presence of catalyst is treated to remove by product, after which adipic acid is isolated by crystallization. According to invention, latter operation is preceded by following intermediate operations: (i) decantation of the two reaction mixture phases to form upper organic phase basically containing cyclohexane and lower phase chiefly solvent, dicarboxylic acids formed in reaction, catalyst and partially other reaction products and unreacted cyclohexane; (ii) distillation of lower phase to separate, on one hand, distillate containing at least part of volatile compounds such as organic solvent, water, and unreacted cyclohexane, cyclohexanone, cyclohexanol, cyclohexyl esters, and possibly lactones, and, on the other hand, distillation residue containing dicarboxylic acids formed in reaction and catalyst; (iii) crude adipic acid is purified in aqueous solution by hydrogenation and/or oxidation followed by crystallization and recrystallization of purified adipic acid from water. Light absorption of purified product at wavelength 454 nm is in 12 and 8 times weaker than shows classically purified adipic acid. EFFECT: increased purity of product. 17 cl, 1 tbl, 2 ex
