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 located in the main channels of KL zeolite in the presence of NH3 have been found by infrared spectroscopy. The interaction of NH3 with the framework atoms and/or the remaining K+ cations located in site D and site C can desorb only the benzene previously adsorbed on K+ cations. The oxygen atoms of the 12-membered ring (12R window) in KL zeolite, which is expected to be a potential adsorption site according to the theoretical 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.