Full Text Available
Note: Clicking the button above will open the full text document at the original institutional repository in a new window.
The characterization and elimination of the external acidity of ZSM-5
The zeolite ZSM-5 is well-known for its unique intersecting channel system. This channel system has a great bearing on the shape-selective properties and the long life-times of ZSM-5. In this study, ZSM-5 was modified in various ways to eliminate the external acidity of the catalyst to further impro...
Saved in:
| Main Author: | |
|---|---|
| Other Authors: | |
| Format: | Thesis |
| Language: | English |
| Published: |
Department of Chemical Engineering
2016
|
| Subjects: | |
| Tags: |
No Tags, Be the first to tag this record!
|
| _version_ | 1867611275366760448 |
|---|---|
| access_status_str | Open Access |
| author | Weber, Reinier Willem |
| author2 | Fletcher, Jack |
| author_browse | Fletcher, Jack Weber, Reinier Willem |
| author_facet | Fletcher, Jack Weber, Reinier Willem |
| author_sort | Weber, Reinier Willem |
| collection | Thesis |
| description | The zeolite ZSM-5 is well-known for its unique intersecting channel system. This channel system has a great bearing on the shape-selective properties and the long life-times of ZSM-5. In this study, ZSM-5 was modified in various ways to eliminate the external acidity of the catalyst to further improve these properties, and the success and effects of these modifications were investigated primarily using temperature programmed desorption techniques. The internal surface of ZSM-5, a medium pore zeolite, plays a major role in the shape selective properties of this catalyst, due to the diffusional restrictions imposed by the channel system on bulky molecules. Even though the number of acid sites on the external surface is small compared to the total number of acid sites, these easily accessible and non-shape selective acid sites may provide a high turnover rate for non-shape selective reactions. Furthermore, the main cause of deactivation of ZSM-5 is thought to be the formation of polyaromatic molecules on the external surface, which block access to the channels of the catalyst. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/18301 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2016 |
| publishDateRange | 2016 |
| publishDateSort | 2016 |
| publisher | Department of Chemical Engineering |
| publisherStr | Department of Chemical Engineering |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/18301 The characterization and elimination of the external acidity of ZSM-5 Weber, Reinier Willem Fletcher, Jack O'Connor, Cyril Chemical Engineering The zeolite ZSM-5 is well-known for its unique intersecting channel system. This channel system has a great bearing on the shape-selective properties and the long life-times of ZSM-5. In this study, ZSM-5 was modified in various ways to eliminate the external acidity of the catalyst to further improve these properties, and the success and effects of these modifications were investigated primarily using temperature programmed desorption techniques. The internal surface of ZSM-5, a medium pore zeolite, plays a major role in the shape selective properties of this catalyst, due to the diffusional restrictions imposed by the channel system on bulky molecules. Even though the number of acid sites on the external surface is small compared to the total number of acid sites, these easily accessible and non-shape selective acid sites may provide a high turnover rate for non-shape selective reactions. Furthermore, the main cause of deactivation of ZSM-5 is thought to be the formation of polyaromatic molecules on the external surface, which block access to the channels of the catalyst. 2016-03-28T14:38:08Z 2016-03-28T14:38:08Z 1993 Master Thesis Masters MSc (Eng) http://hdl.handle.net/11427/18301 eng application/pdf Department of Chemical Engineering Faculty of Engineering and the Built Environment University of Cape Town |
| spellingShingle | Chemical Engineering Weber, Reinier Willem The characterization and elimination of the external acidity of ZSM-5 |
| thesis_degree_str | Master's |
| title | The characterization and elimination of the external acidity of ZSM-5 |
| title_full | The characterization and elimination of the external acidity of ZSM-5 |
| title_fullStr | The characterization and elimination of the external acidity of ZSM-5 |
| title_full_unstemmed | The characterization and elimination of the external acidity of ZSM-5 |
| title_short | The characterization and elimination of the external acidity of ZSM-5 |
| title_sort | characterization and elimination of the external acidity of zsm 5 |
| topic | Chemical Engineering |
| url | http://hdl.handle.net/11427/18301 |
| work_keys_str_mv | AT weberreinierwillem thecharacterizationandeliminationoftheexternalacidityofzsm5 AT weberreinierwillem characterizationandeliminationoftheexternalacidityofzsm5 |