Oxidation of Cyclohexanone to Adipic Acid with 30% H_2O_2 Catalyzed by WO_3

Adipic acid was synthesized by WO_(3)-catalyzed oxidation of cyclohexanone with 30% hydrogen peroxide in the absence of organic solvent and phase-transfer catalyst.The influence of reaction conditions such as catalyst amount,hydrogen peroxide amount,reaction temperature and time on the oxidation was investigated.Under the optimal conditions,i.e.when n(cyclohexanone)∶n(hydrogen peroxide)∶n(tungsten trioxide) was 100∶500∶2,and the reaction temperature was 120 ℃,the reaction time was 6 h,the isolated yield of adipic acid could reach 80.3% and its purity was 99.8%.The catalyst could be reused for 5 times and the isolated yield of adipic acid was still above 70.2%.