Clean oxidation of cyclohexanol to adipic acid with H_2O_2 using tungstomolybdophosphate acid as catalyst

Adipic acid was synthesized by tungstomolybdophosphate acid-catalyzed oxidation of cyclohexanol with 30% hydrogen peroxide in the absence of organic solvent and phase-transfer agent. The effects of amount of catalyst and of 30% H2O2,reaction temperature and time were investigated. Under the optimal conditions,i.e.,molar ratio of cyclohexanone:tungstomolybdophosphate acid: hydrogen peroxide 100∶0.15∶500,reaction temperature 120℃,reaction time 8 h,the isolated yield of adipic acid could reach 82.0%.