Diffusion of isobutane in ZSM-5 zeolite: A comparison of quasi-elastic neutron scattering and supported membrane results
Journal Article
·
· Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical
- Inst. Francais du Petrole, Rueil-Malmaison (France)
- Inst. de Recherches sur la Catalyse, Villeurbanne (France)
- Univ. Joseph Fourier, St. Martin d`Heres (France). Lab. de Spectrometrie Physique
The use of ZSM-5 zeolites is widely recommended for adsorption separation processes mainly in the field of refining and for gas processing. One of the most promising applications of ZSM-5 zeolites is the kinetic separation of alkane isomers for upgrading the octane number of gasoline. Isobutane diffusivities in ZSM-5 zeolite have been measured by quasi-elastic neutron scattering (QENS) and supported membrane techniques. This is the first diffusivity measurement of a branched alkane inside a zeolite of MFI type using a microscopic method. The self-diffusion coefficient derived from QENS is 3 {times} 10{sup {minus}12} m{sup 2}/s at 500 K. The diffusivity obtained with the supported membrane is 1 order of magnitude larger. In view of the large differences usually reported in the literature between microscopic and macroscopic techniques, the comparison between QENS and supported membrane data is quite satisfactory. The activation energy for diffusion determined from QENS is 27 kJ/mol. Because of the variation of loading due to temperature changes, an apparent activation energy is obtained with the supported membrane; it is 34 kJ/mol. In this zeolite, the diffusion of branched hydrocarbons is much slower than that of linear alkanes; the diffusion coefficient of isobutane is found to be 3 orders of magnitude lower than that of n-butane by QENS.
- OSTI ID:
- 335250
- Journal Information:
- Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical, Journal Name: Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical Journal Issue: 7 Vol. 103; ISSN 1089-5647; ISSN JPCBFK
- Country of Publication:
- United States
- Language:
- English
Similar Records
MFI-type ferrisilicate catalysts for the oxidative dehydrogenation of alkanes
An Adsorption Study of CH4 on ZSM-5, MOR, and ZSM-12 Zeolites
Preparation of zeolite ZSM-5 membranes by in-situ crystallization on porous {alpha}-Al{sub 2}O{sub 3}
Journal Article
·
Wed Nov 30 23:00:00 EST 1994
· Journal of Catalysis
·
OSTI ID:47987
An Adsorption Study of CH4 on ZSM-5, MOR, and ZSM-12 Zeolites
Journal Article
·
Sun Dec 06 19:00:00 EST 2015
· Journal of Physical Chemistry. C
·
OSTI ID:1387606
Preparation of zeolite ZSM-5 membranes by in-situ crystallization on porous {alpha}-Al{sub 2}O{sub 3}
Journal Article
·
Mon May 01 00:00:00 EDT 1995
· Industrial and Engineering Chemistry Research
·
OSTI ID:178420