Oxodiperoxo tungsten complex-catalyzed synthesis of adipic acid with hydrogen peroxide

An amphiphilic oxodiperoxo complex of tungsten using 8-quinolinol (QOH) as ligand has been synthesized and characterized by elemental analyses, gravimetry, chemistry titration, TG/DSC, IR and UV-vis spectroscopy. Oxidation of cyclohexene, cyclohexanol, cyclohexanone, cyclohexene oxide and 1,2-cyclohexane-diol to adipic acid in one-step was conducted by this complex catalyst using 30 wt.% hydrogen peroxide in the absence of organic solvent and phase-transfer catalyst. The effect of the reaction conditions on the oxidation of cyclohexene was studied by varying the amount of the catalyst, reaction temperature, reaction time and the amount of hydrogen peroxide. The results showed that oxodiperoxo tungsten complex with QOH as ligand could achieve 89.8% yield of adipic acid at 90°C by refluxing for 20 h.