Cu(II), Co(II) and Ni(II) Complexes Installed on Functionalized Silica Surface for Hydrogen Peroxide Assisted Cyclohexane Oxidation

In this work, Cu(II), Co(II) and Ni(II) complexes of the Schiff base ((S,E)-2-(3,4-dimethoxybenzylideneamino)-3-(1H-imidazol-4-yl)propionic acid) were synthesized and subsequently anchored onto amine functionalized silica. They were characterized by FT-IR, UV–vis., 29Si NMR, TG-DTG, ESR, FE-SEM and AFM techniques, and employed as catalysts in cyclohexane oxidation using hydrogen peroxide oxidant. Silica supported Cu(II) catalyst was shown the highest catalytic activity (70%) than rest of the catalysts used. On the other hand, all the complexes were selective as they yield only cyclohexanol and cyclohexanone. Silica supported catalysts were maintained their catalytic activity over five successive catalytic run. As these catalysts are selective, reusable and functioning well with hydrogen peroxide, they could design the environment friendly catalytic system for effective cyclohexane oxidation.