Iron, cobalt or nickel substituted MCM-41 molecular sieves for oxidation of hydrocarbons

A series of mesoporous Fe-MCM-41, Co-MCM-41 and Ni-MCM-41 catalysts with different quantity of the metal incorporated in the framework were synthesized and characterized (as-synthesized samples and those after reaction) by X-ray diffraction pattern (XRD), N-2 adsorption-desorption, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) techniques. The effect of the incorporated metal on the MCM-41 surface hydroxyl groups has been evidenced. The catalytic activity and selectivity of these catalysts in liquid phase oxidation of 1-hexene, styrene and benzene with hydrogen peroxide were studied. The structure and morphology of the catalysts before and after reaction were also compared. The results show a high activity and selectivity of catalysts having higher Co content to benzaldehyde from styrene or phenol from benzene, and a low activity of all prepared catalysts in the oxidation of the 1-hexene. The activity and efficiency of H2O2 increases with the metal content and depend on the reaction parameters such as temperature, molar ratio of the reactants and the solvent, and the nature of the reactor. (C) 2001 Elsevier Science B.V. All rights reserved.