Investigation of the benzene molecule adsorbed on faujasite zeolite using double quantum filtered NMR spectral analysis

Deuteron NMR relaxation studies including double quantum filtered (DQF) spe ctral analyses, TI, and line widths are used to probe the dynamics and exch ange process of various-loading benzene molecules adsorbed into NaY and dea luminated Y (DAY) including ultrastable Y (USY) zeolite, DQF Nh IR is a ver y sensitive method to determine the residual quadrupolar interaction result ing from the local order, III this work, we modified the cone model to desc ribe the in-plane rotation around the hexad axis anti the restricted wobbli ng motion of the benzene ring on the surface of the interaction site. The i n-plane rotation and wobbling motion of adsorbed benzene molecules reflects a host-guest effect on the isolated adsorption site and also the mobility in the cage. In addition, the effect of a site-to-site hopping process resu lts in a. small net residual quadrupolar interaction. With increased loadin g, the in-plane rotation of benzene is significantly hindered in all faujas ites but the population of adsorbed benzene dramatically reduces in DAY (in cluding USY) systems only. This indicates the nature of site interaction on benzene molecules in a supercage. The population profile of adsorbate thus determined provides useful knowledge of loading effect, and the site inter actions and distribution.