Infrared in situ characterization of HY zeolite acid sites during cyclohexene transformation

The construction of cell suitable for in situ monitoring of catalysts is described. The apparatus has been used to elucidate the nature of the acid sites responsible for coke formation during cyclohexene conversion on dealuminated HY zeolites. It is suggested that the most acidic Bronsted sites are primarily responsible for coke formation. Activation of cyclohexene probably occurs through hydride transfer between adsorbed unsaturated carbocations and gas phase cyclohexene.