FT-IR evidence of the interaction of benzothiophene with the hydroxyl groups of H-MFI and H-MOR zeolites

The interaction of benzothiophene (BT) with H-MFI and H-MOR has been investigated by FT-IR spectroscopy. The results from BT adsorption on acid H-MFI and H-MOR coupled with the study of adsorbed naphthalene show that two types of interactions occur between BT and the strongly acidic protonic sites of the zeolites: one interaction through the sulfur lone electron pair and another one, similar to that observed with naphthalene, involving the π-type electron cloud. With the external silanols, only a weak hydrogen bonding type interaction with the π-type electron cloud of the aromatic ring of BT was clearly observed.