Surface acidity and catalytic activity of mixed Fe-AI and er-AI pillared montmorillonites

The incorporation of transition metal oxide pillars such as those of iron and chromium along with Al20, pillars within the interlayers of a montmorillonite clay is investigated. The surface acidity of these catalysts has been evaluated for the first time employing the equilibrium adsorption of an electron donor, perylene, and the results are compared with those obtained by temperature programmed desorption of ammonia. The principle is based on the ability of a catalyst surface site to accept a ~ingle electron from an electron donor like perylene to form charge transfer complexes and the amount of adsorbed species is measured quantitatively by UV-vis spectroscopy. Fina1\y, an attempt has been made to correlate the acidity determined by the two independcnt methods and the catalytic activity of present systems in the benzoylation of toluene with benzoyl chloride. Incorporation of Fe and Cr has changed the properties of AI pitlared montmorillonite. Fe pillared systems have been found to be vcry good catalysts for benzoylation reaction. Extensive research on pillared smectites has proven their applications in the field of heterogeneous catalysis and adsorption l.5. Several studies have shown that pillared clays with single metal oxide clusters as pillars in the inter layer region are active catalysts for cracking reactions, alkylation reaction