Highly dispersed iron oxide nanoclusters supported on ordered mesoporous SBA-15: A very active catalyst for Friedel-Crafts alkylations

Iron oxide supported on ordered mesoporous SBA-15 was prepared by impregnating as-synthesized SBA-15 with a methanolic solution of Fe(NO3)(3)(H2O)-H-center dot, characterized by X-ray diffraction (XRD), N-2 sorption, transmission electron microscopy (TEM), and UV-vis spectroscopy. Characterization revealed that iron oxide was present as highly dispersed nanoclusters in the well-ordered mesoporous channels of SBA-15. The supported material still maintained its ordered mesoporous structure similar to SBA-15 and possessed high surface area, large pore volume and uniform pore size. The benzylation of benzene by benzyl chloride showed that iron oxide nanoclusters-supported SBA-15 was a very active catalyst and able to activate the reactant at relatively low temperature such as 313 K. Moreover, the catalyst could be reused. Such outstanding catalytic performance should be attributed to the presence of active sites from iron oxide nanoclusters, large surface area, open pore channels, and high pore volume. Additionally, the catalyst has found potential applications in other Friedel-Crafts alkylations, especially to large molecular reactions due to its ordered mesoporous structure. (c) 2005 Elsevier B.V. All rights reserved.