Application of Recycled Lamp Tungsten Filament as Catalyst in the Oxidation of Cyclohexanone to Adipic Acid by H_2O_2

Using recycled lamp tungsten filament as the precursor of catalyst,adipic acid was synthesized from the oxidation of cyclohexanone by 30% H2O2 without the presence of any organic solvent,acidic additives and phase transfer agents.The IR and TG results indicate that nascent peroxotungstic acid is the active catalytic component obtained from the oxidation of recycled lamp tungsten filament by H2O2.It converts to tungstic acid finally.After 6h refluxing,a 63.7% yield of adipic acid could be attained using the above catalyst in optimized reaction system consisting of 100 mmol of cyclohexanone in 50 mL 30% H2O2,and with 1.5% molar fraction of catalyst in cyclohexanone.Under identical conditions the yield is 10% ～ 18% higher than those from using tungstic acid or WO3 as the catalyst.