LOCATION OF BENZENE IN KL UPON COADSORPTION OF NH3 - A MOLECULAR RECOGNITION EFFECT

No change in the location of benzene with and without coadsorption of NH3 and only one kind of interaction between benzene and K+ cations lo cated in the main channels of KL zeolite in the presence of NH3 have b een found by infrared spectroscopy. The interaction of NH3 with the fr amework atoms and/or the remaining K+ cations located in site D and si te C can desorb only the benzene previously adsorbed on K+ cations. Th e oxygen atoms of the 12-membered ring (12R window) in KL zeolite, whi ch is expected to be a potential adsorption site according to the theo retical calculations a nd with regard to its higher average basicity, is not an adsorption site for benzene even in the presence of ammonia. The present work combined with previously published results reveals a molecular recognition effect in benzene adsorption on zeolites.