Oxidation Of Cycloketone By Hydrogen Peroxide With Metal Oxides Supported On Graphene Oxide

Metal oxides supported graphene oxide catalysts were used to catalyze the oxidation of cyclohexanone with hydrogen peroxide and the product of lactone had a good application prospect in the fields of daily chemicals,medicine,pesticides and so on.In this paper,hydrogen peroxide was used as oxidant to study the activity and selectivity of cyclohexanone catalyzed by metal oxides supported graphene oxide catalysts.The suitable reaction conditions were obtained and the possible catalytic reaction mechanism was put forward,which laid a foundation for application of green oxidation reaction.Graphene oxide was prepared by modified Hummers method in two steps,and supported nano Fe₃O₄ particles to form composite catalysts.The morphology and structure of the catalysts were characterized by FT-IR,XRD,SEM,TEM,XPS and VSM.The oxidation characteristics of hydrogen peroxide catalyzed by the catalysts were investigated.It was found that under mild conditions,2-methylcyclohexanone was used as the reaction substrate,Fe₃O₄@GO catalyst catalyzed the oxidation of hydrogen peroxide.The conversion of 2-methylcyclohexanone reached 89%and the yield was 84%.Under the same reaction conditions,the catalysts exhibit certain catalytic activity and selectivity for the oxidation of other cyclohexanones by hydrogen peroxide.In addition,graphene oxide was prepared by modified Hummers method in one step,and graphene oxide catalysts supported on Ni and V composite oxides were prepared by hydrothermal method.The catalysts were characterized by XRD,FT-IR,SEM,TEM and Raman.It was found that the conversion of 2-heptyl cyclopentanone was 82%with the selectivity of 96%.The composite catalyst could be recycled.The possible reaction mechanism of cyclohexanone oxidation with hydrogen peroxide catalyzed by Fe₃O₄@GO and NiV=O@RGO was proposed.It was found that GO and RGO as supports,the active components of trivalent iron ions in Fe₃O₄ and the active sites of nickel-vanadium oxide could coordinate with the carbonyl oxygen atoms of cyclohexanone,which increased the positive electricity of carbonyl carbon and facilitated the attack of carbonyl carbon by hydrogen peroxide.Lactone was obtained after migration and rearrangement.