Diffusion behavior of the benzene molecule in faujasite-type zeolite studied by double quantum filtered NMR

✍ Scribed by Yu-Huei Chen; Lian-Pin Hwang

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 110 KB
• Volume: 37
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/(sici)1097-458x(199912)37:13<s84::aid-mrc537>3.0.co;2-9

✦ Synopsis

Deuteron NMR relaxation methods including double quantum filtered (DQF) spectral analyses were examined to study the dynamics of benzene molecules adsorbed in faujasite-type zeolite. To describe the dynamics of benzene molecules, a modified cone model involving in-plane rotation, wobbling motion and the characteristic order parameter was applied. The characteristic order parameter describes the intracage restricted reorientation for a single-site adsorption. For multiple-site adsorption such as in NaY, the site-to-site hopping processes result in cage disorder and yield a small characteristic order parameter. The wobbling motion is induced by the diffusive motion and therefore the correlation time of wobbling motion may be invoked to estimate the self-diffusion coefficient of benzene adsorbed in NaY, DAY, USY and NaX. Comparisons with kinetic Monte Carlo calculation, pulsed field gradient measurement, and other NMR relaxation studies are discussed.