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The measurement and modelling of the intracrystalline diffusion of cyclohexane in ZSM-5 using zero length column chromatography
Bibliography: p. 97-102.
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| Format: | Thesis |
| Language: | English |
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Department of Chemical Engineering
2014
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| _version_ | 1867613291589664768 |
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| access_status_str | Open Access |
| author | Duncan, Warwick |
| author_browse | Duncan, Warwick |
| author_facet | Duncan, Warwick |
| author_sort | Duncan, Warwick |
| collection | Thesis |
| description | Bibliography: p. 97-102. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/8743 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:33:48.261Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2014 |
| publishDateRange | 2014 |
| publishDateSort | 2014 |
| 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:11427/8743 The measurement and modelling of the intracrystalline diffusion of cyclohexane in ZSM-5 using zero length column chromatography Duncan, Warwick Chemical Engineering Bibliography: p. 97-102. Zeolites are important solid acid catalysts largely because of their microporous nature giving them strong shape selective properties. This shape selectivity may be improved by depositing an inert (e. g. silaceous) layer on the surface of the catalyst crystals, which inertises non-shape selective surface acid sites and increases diffusional transport resistances. This thesis presents an investigation, using the zero length column (ZLC) method, into changes in the diffusional properties of cyclohexane in ZSM-5 that has had tetraethoxysilane deposited on the surface in the liquid phase. Theoretical analyses of the ZLC technique and its use in a detailed study of cyclohexane in unmodified ZSM-5 were performed in order to prove the reliability of the technique and measure baseline behaviour of the selected system. The ZLC method is a chromatographic technique for the measurement of diffusion coefficients in porous sorbents. Originally developed for gaseous hydrocarbon / zeolite powder systems, it has been experimentally extended to the measurement of liquid sorbate systems, macroporous zeolite pellets and resins and the measurement of self-diffusion through tracer exchange. The technique is robust against the intrusion of external heat and mass transfer effects by the use of relatively high flow rates and small catalyst samples, Analysis of the desorption curves is simple: the slope of the linear (on semilogarthmic axes) long time region gives the diffusional time constant. This so-called 'long time' analysis gives an accurate result for the diilusional time constant. 2014-10-24T07:29:54Z 2014-10-24T07:29:54Z 2001 Doctoral Thesis Doctoral PhD http://hdl.handle.net/11427/8743 eng application/pdf Department of Chemical Engineering Faculty of Engineering and the Built Environment University of Cape Town |
| spellingShingle | Chemical Engineering Duncan, Warwick The measurement and modelling of the intracrystalline diffusion of cyclohexane in ZSM-5 using zero length column chromatography |
| thesis_degree_str | Doctoral |
| title | The measurement and modelling of the intracrystalline diffusion of cyclohexane in ZSM-5 using zero length column chromatography |
| title_full | The measurement and modelling of the intracrystalline diffusion of cyclohexane in ZSM-5 using zero length column chromatography |
| title_fullStr | The measurement and modelling of the intracrystalline diffusion of cyclohexane in ZSM-5 using zero length column chromatography |
| title_full_unstemmed | The measurement and modelling of the intracrystalline diffusion of cyclohexane in ZSM-5 using zero length column chromatography |
| title_short | The measurement and modelling of the intracrystalline diffusion of cyclohexane in ZSM-5 using zero length column chromatography |
| title_sort | measurement and modelling of the intracrystalline diffusion of cyclohexane in zsm 5 using zero length column chromatography |
| topic | Chemical Engineering |
| url | http://hdl.handle.net/11427/8743 |
| work_keys_str_mv | AT duncanwarwick themeasurementandmodellingoftheintracrystallinediffusionofcyclohexaneinzsm5usingzerolengthcolumnchromatography AT duncanwarwick measurementandmodellingoftheintracrystallinediffusionofcyclohexaneinzsm5usingzerolengthcolumnchromatography |