Catalytic oxidation of p-xylene in water by cobalt(III) cubane cluster

A tetrameric cubane complex Co4III(μ3-O)4(μ-O2CCH3)4(4-CNpy)4(I) has been prepared in good yield by H2O2 oxidation of CoII in presence of CH3CO22- and 4-cyanopyridine (4-CNpy) in methanol. The complex has been characterized by various physicochemical techniques including elemental analysis, UV–Vis, infrared and 1H NMR spectroscopy and cyclic voltammetry. Oxidation of p-xylene under mild pressure with dioxygen in aqueous media has been studied using the tetrameric cubane complex I as the catalyst. The main oxidation product in the catalytic reaction is p-toluic acid is, with terephthalic acid forming in traces. The reaction rate and product yield (maximum p-toluic acid yield ∼36% at 20 bar oxygen pressure at 130 °C) are linearly dependent upon the applied pressure and reaction temperature.

A new tetrameric cubane complex Co4III(μ3-O)4(μ-O2CCH3)4(4-CNpy)4 has been studied as a homogeneous catalyst for the oxidation of p-xylene with dioxygen in aqueous media.Figure optionsDownload as PowerPoint slide