Facile heterogenization of homogeneous ferrocene catalyst on SBA-15 and its hydroxylation activity

Hexagonally ordered mesoporous silica SBA-15 was synthesized with amino propyl groups by direct co-condensation method using triblock co-polymer (P123) as a template, tetra ethyl orthosilicate as a silica source under conventional SBA-15 synthesis conditions. Amino propyl trimethoxy silane was utilized for introducing SBA-15 with propyl amine anchoring moiety. Ferrocene was anchored to SBA-15 post-synthetically by the condensation of amine group from propylamine SBA-15 with the carbonyl group of ferrocenecarboxaldehyde. The structural ordering and the textural properties of propyl amine functionalized SBA-15 (SBA-15-NH2) and further ferrocene tethered SBA-15 (SBA-15-N = ferrocene) were characterized by low angle XRD and nitrogen gas adsorption techniques. The attached organic moieties were identified by mid-infrared (MIR) and near-infrared (NIR) spectroscopy. The ferrocene functionalized SBA-15 is highly active towards the hydroxylation of benzene to phenol. The catalyst was reused without significant loss in activity.