Molecular mobility of methane adsorbed on ZSM-5 containing co-adsorbed benzene, and the location of the benzene molecules

Abstract

The molecular mobility of methane adsorbed on ZSM-5 as investigated by both the n.m.r. pulsed field gradient technique and proton magnetic relaxation studies is found to decrease significantly with increasing amounts of coadsorbed benzene molecules. Comparison with a computer simulation of the random-walk process within the ZSM-5 network suggests that the channel intersections, rather than the channel segments between them, should form the adsorption sites of the benzene molecules. Both the second moments of the proton magnetic resonance lines of methane, as determined from the transverse relaxation times, and the laser-Raman spectra of benzene adsorbed on ZSM-5 are in agreement with this model.