OXIDATION OF CYCLOHEXANE USING Co-Fe/Al2O3 CATALYSTS: SYNTHESIS, CHARACTERISATION AND REACTIVITY

Abstract

A series of iron and cobalt supported over alumina catalysts were synthesized by incipient wetness impregnation method. The supported 20FexCo100-x /Al2O3 catalysts were characterized by XRD, BET, FE-SEM, FTIR and TGA analysis. The synthesized catalysts were studied for selective oxidation of cyclohexane using a batch reactor. The catalytic oxidation of cyclohexane was studied by varying various parameters like total metal loading, support amount, oxidant/cyclohexane ratio and different precursor ratio. The study suggested that the 20Fe0.6Co0.4/Al2O3 catalyst was most active for the cyclohexane conversion. Alumina was found to be most suitable support. The reaction temperature was found to be effective 70°C for highest products yields, using H2O2 to Cyclohexane ratio 1.5:1, and acetonitrile as solvent. TGA analysis shows that the catalyst had lost all physically and chemically bond nitrates and hydroxyl at 460°C. The XRD results corroborates the formation of different oxides and mixed oxides as Co3O4, Fe2O3, Co3O4–Fe3O4 and Fe2O3–Co2O3. FE-SEM images shows that iron molecules gives flakes like structure and as the amount of cobalt loading in the catalyst is increased BET surface area is decreased due to large fraction of cobalt molecule which in turn blocks the pore.