Materials Chemistry and Physics, Vol.165, 72-78, 2015
Iron incorporated Ia3d mesostructured silicate prepared at room temperature: Excellent Friedel-Crafts benzylation catalyst
The incorporation of Fe3+ ions in the framework of FDU-5, a cubic Ia3d silicate, with different Si/Fe ratio have been synthesized for the first time in room temperature under acidic condition employing solvent drying method without the necessity of pH adjustments. The synthesized samples, Fe-FDU-5, were investigated using different characterization techniques including XRD, N-2 sorption, TEM, UV-vis, ESR, NH3-TPD, H-2-TPR and pyridine-absorbed FT-IR techniques. The presence of isolated Fe3+ species and extraframework Fe2O3 particles were confirmed at all loadings (1.2-4.5 wt% Fe). The N-2 sorption studies of Fe-FDU-5 materials evidenced a specific surface area of 340-394 m(2)/g, total pore volume of 0.41 -0.44 cm(3)/g and a narrow pore distribution of 4.4-4.9 nm. Fe-FDU-5 are excellent catalysts for benzylation of benzene and is independent of acid sites. A near complete conversion of benzyl chloride (BnCl) was achieved in 20 min over Fe-FDU-5 where as other metal ions including Al3+, Sn4+ and Mn(2+)or Mn3+ supported on various silica supports yielded only 3-8% BnCl conversion. Moreover, both framework Fe3+ and extraframework octahedral Fe species are found beneficial for this reaction, however, bulk Fe2O3 species are inactive. (C) 2015 Elsevier B.V. All rights reserved.
Keywords:Amorphous materials;Sol-gel growth;Electron microscopy;Electron resonance;Visible and ultraviolet spectrometers