The characterization and elimination of the external acidity of ZSM-5.

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dc.contributor.authorWeber, R
dc.contributor.authorFletcher, J
dc.contributor.authorMöller, K
dc.contributor.authorO'Connor, C
dc.date.accessioned2016-07-29T10:25:43Z
dc.date.available2016-07-29T10:25:43Z
dc.date.issued1996
dc.date.updated2016-07-29T07:45:34Z
dc.description.abstractThe external acidity of ZSM-5 was modified either by coating the crystals with a silicalite shell or by chemical vapour deposition (CVD) of tetraethoxysilane (TEOS). Temperature programmed desorption (TPD) techniques were used to characterize the acidity changes arising from these modifications. Ammonia and pyridine were used as probes for the total acidity, and 4-methylquinoline was used to probe the external acidity of the modified and unmodified ZSM-5 samples. Si/Al ratios of the modified samples were also used to characterize the samples. Both methods of modification were able to make the external acid sites inert. Chemical vapour deposition was found to be a better method, because the external surface acidity was eliminated without significantly changing the catalyst in terms of total acidity. Optimum elimination of the external surface acidity by CVD was obtained for the sample with the higher deposition time (16 h) and temperature (400°C). Optimum elimination of the external surface acidity using the silicalite shell method was obtained using the detemplated NH4-form of the parent crystal as seed material. The channel structures of crystals modified by both processes remained accessible to ammonia and pyridine.en_ZA
dc.identifierhttp://dx.doi.org/10.1016/0927-6513(96)00026-0
dc.identifier.apacitationWeber, R., Fletcher, J., Möller, K., & O'Connor, C. (1996). The characterization and elimination of the external acidity of ZSM-5. <i>Microporous Materials (now incoporated in Microporous and Mesoporous Materials)</i>, http://hdl.handle.net/11427/21022en_ZA
dc.identifier.chicagocitationWeber, R, J Fletcher, K Möller, and C O'Connor "The characterization and elimination of the external acidity of ZSM-5." <i>Microporous Materials (now incoporated in Microporous and Mesoporous Materials)</i> (1996) http://hdl.handle.net/11427/21022en_ZA
dc.identifier.citationWeber, R. W., Fletcher, J. C. Q., Möller, K. P., & O'Connor, C. T. (1996). The characterization and elimination of the external acidity of ZSM-5. Microporous Materials, 7(1), 15-25.en_ZA
dc.identifier.issn1387-1811en_ZA
dc.identifier.ris TY - Journal Article AU - Weber, R AU - Fletcher, J AU - Möller, K AU - O'Connor, C AB - The external acidity of ZSM-5 was modified either by coating the crystals with a silicalite shell or by chemical vapour deposition (CVD) of tetraethoxysilane (TEOS). Temperature programmed desorption (TPD) techniques were used to characterize the acidity changes arising from these modifications. Ammonia and pyridine were used as probes for the total acidity, and 4-methylquinoline was used to probe the external acidity of the modified and unmodified ZSM-5 samples. Si/Al ratios of the modified samples were also used to characterize the samples. Both methods of modification were able to make the external acid sites inert. Chemical vapour deposition was found to be a better method, because the external surface acidity was eliminated without significantly changing the catalyst in terms of total acidity. Optimum elimination of the external surface acidity by CVD was obtained for the sample with the higher deposition time (16 h) and temperature (400°C). Optimum elimination of the external surface acidity using the silicalite shell method was obtained using the detemplated NH4-form of the parent crystal as seed material. The channel structures of crystals modified by both processes remained accessible to ammonia and pyridine. DA - 1996 DB - OpenUCT DP - University of Cape Town J1 - Microporous Materials (now incoporated in Microporous and Mesoporous Materials) LK - https://open.uct.ac.za PB - University of Cape Town PY - 1996 SM - 1387-1811 T1 - The characterization and elimination of the external acidity of ZSM-5 TI - The characterization and elimination of the external acidity of ZSM-5 UR - http://hdl.handle.net/11427/21022 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/21022
dc.identifier.vancouvercitationWeber R, Fletcher J, Möller K, O'Connor C. The characterization and elimination of the external acidity of ZSM-5. Microporous Materials (now incoporated in Microporous and Mesoporous Materials). 1996; http://hdl.handle.net/11427/21022.en_ZA
dc.languageengen_ZA
dc.publisherElsevieren_ZA
dc.publisher.institutionUniversity of Cape Town
dc.rightsCreative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)*
dc.rights.urihttp://creativecommons.org/licenses/by-nc-nd/4.0/en_ZA
dc.sourceMicroporous Materials (now incoporated in Microporous and Mesoporous Materials)en_ZA
dc.source.urihttp://www.journals.elsevier.com/microporous-and-mesoporous-materials/
dc.subject.otherZSM-5
dc.subject.otherTPD
dc.subject.otherExternal surface
dc.subject.otherSilicalite shell
dc.subject.otherCVD
dc.titleThe characterization and elimination of the external acidity of ZSM-5.en_ZA
dc.typeJournal Articleen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceArticleen_ZA
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