Catalytic oxidation of cyclic hydrocarbons with hydrogen peroxide using Fe complexes immobilized into montmorillonite

Abstract [Fe(Ligand)x]2+ complexes immobilized into montmorillonite ([Fe(Ligand)x]2+@Mont, Ligand: 2,2′;6′,2′'-terpyridine (x = 2), 1,10-phenanthroline (x = 3), and 2,2′-bipyridine (x = 3)) were prepared by an ion-exchange method whereby cations present within montmorillonite (probably Ca2+) were replaced by [Fe(Ligand)x]2+ complexes provided by [Fe(Ligand)x](ClO4)2. The catalytic properties of the species obtained were then investigated in the oxidation of cyclic hydrocarbons, such as cyclohexane and benzene, with H2O2. The catalytic oxidation of cyclohexane and benzene with H2O2 over [Fe(Ligand)x]2+@Mont catalysts proceeded, and the desired alcohols were obtained as the main reaction products, whereas no catalytic activity was displayed by neat montmorillonite. Regardless of the reaction conditions, [Fe(terpy)2]2+@Mont (terpy stands for 2,2′;6′,2′'-terpyridine) exhibited the best catalytic performance in the oxidation of the mentioned substrates by H2O2, among all the catalysts tested.