Infrared study of the adsorption of propene and di-isopropyl ether on rutile

Abstract

Infrared spectra are reported of propene and di-isopropyl ether adsorbed on rutile which had been preheated at 400 K. Propene was involved in hydrogen-bonding interactions with surface hydroxyl groups at 306 K and was probably also adsorbed through π-complex formation at Lewis-acidic surface sites. Chemisorption to give adsorbed isopropoxide ions occurred at higher temperatures and preceded subsequent oxidation to surface carboxylate species. Interactions between rutile and di-isopropyl ether were similarly dependent on temperature and involved hydrogen-bond formation, adsorption on Lewis-acidic sites and the appearance of infrared bands due to chemisorbed isopropoxide and carboxylate ions.