FTIR STUDY OF THE ADSORPTION AND TRANSFORMATION OF ALLYLBENZENE OVER OXIDE CATALYSTS

The interaction of allylbenzene with oxide catalyst surfaces having di fferent surface characters, such as acidic (alumina, titania, silica-a lumina, tungsta-alumina and sulfated titania), basic (magnesium oxide) and redox character (vanadia-titania and magnesium chromite), and wit h slightly reducible transition-metal oxides (zirconium and zinc oxide s) has been investigated by FTIR spectroscopy. For acidic catalysts, p olymerization (sulfated titania) and the formation of 1-phenyl-2-propo xide by the addition of an OH over the vinylic bond have been observed . For ZnO, TiO2 and vanadia-titania the features of a species identifi ed as a pi-allylbenzyl have been observed. For redox surfaces this int ermediate converts rapidly to an oxidized species resulting in benzyli c C-C bond breaking. For MgO and ZrO2 no reaction has been found. The mechanism of C-H activation over these surfaces is briefly discussed.