Clear Oxidation of Cyclohexanone to Adipic Acid Catalyzed by Phosphotungstic Acid with Dawson Structure

Adipic acid is synthesized by H6P2W18O62·32H2O catalyzed oxidation cyclohexanone with 30 percent hydrogen peroxide in the absence of organic solvent and phase-transfer.Influences of the amount of H6P2W18O62·32H2O,hydrogen peroxide,oxalic acid,reaction temperature and reaction time are then recorded and investigated.When the parameters fit in the following formula,that is,n(cyclohexanone)∶n(H2O2)∶n(H2C2O4)∶n(H6P2W18O62·32H2O)=100∶450∶1.0∶0.125,reaction temperature reaches 100℃ and reaction time lasts 5 hours,the isolated yield of adipic acid can reach as high as 74.5%.