Abstract
A one-step surfactant-free synthesis procedure was applied to prepare mesoporous Fe-containing TUD-1 (Fe-TUD-1) with different Si/Fe ratio (100, 50, 20 and 10), using triethanol-amine as a template. Depending on the Fe-loading, different active sites are generated during the synthesis. In samples with a low Fe-loading only isolated tetrahedrally coordinated Fe(III) atoms are formed, while in highly Fe-loaded samples, besides these isolated sites, also nano-particles of Fe2O3 are present inside the mesopores of the TUD-1 silica matrix. The catalytic performance of these Fe-TUD-1 catalysts was evaluated in Friedel-Crafts benzylation of benzene by off-line GC analysis and on-line ATR-FT-IR spectroscopy. The activity per Fe-site was an order of magnitude higher for the samples containing Fe2O3 nano-particles and isolated sites. The synergy of two catalytic centers (particles and isolated sites) is proposed to explain the high performance of the highly loaded samples.