Diffusion of benzene in ZSM-5 measured by the neutron spin-echo technique

Citation
H. Jobic et al., Diffusion of benzene in ZSM-5 measured by the neutron spin-echo technique, J PHYS CH B, 104(30), 2000, pp. 7130-7133
Citations number
35
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
JOURNAL OF PHYSICAL CHEMISTRY B
ISSN journal
15206106 → ACNP
Volume
104
Issue
30
Year of publication
2000
Pages
7130 - 7133
Database
ISI
SICI code
1520-6106(20000803)104:30<7130:DOBIZM>2.0.ZU;2-7
Abstract
The diffusion of benzene in ZSM-5 has been measured by neutron spin-echo. T his technique allows probing for much longer times (20 ns in this work) tha n with conventional quasi-elastic spectrometers. In this zeolite, the diffu sion coefficient of benzene extrapolated to 300 K is 1.3 x 10(-14) m(2) s(- 1) at 300 K, the activation energy being 30 kJ/mol. This is one of the few systems in which agreement can be observed between a microscopic technique and macroscopic methods, that is, gravimetry, frequency-response, infrared, and zero-length column (ZLC) technique. Comparison with molecular simulati on studies shows that inclusion of the lattice flexibility is crucial when the molecule is similar in size to the zeolite pore, as for benzene in MFI.