Green catalytic oxidation of cyclohexanone to adipic acid

Synthesis of adipic acid by catalytic oxidation of cyclohexanone with 30% hydrogen peroxide in the presence of sodium tungstate catalyst can be well performed under reflux temperature. The adipic acid isolated yield reaches to 82.1%, and the purity of the product is also very high. The catalytic oxidation reaction takes place without any organic solvent and phase-transfer agent. The effects over different acidic ligands and the amount of the ligand on the catalytic oxidation were investigated. The catalysts exhibit high activity for the catalytic oxidation reaction of the mixture of cyclohexanone and cyclohexanol to adipic acid by 30% hydrogen peroxide under reflux temperature.