{"id":{"repo_id":"cape-town","oai_identifier":"oai:open.uct.ac.za:11427/19813"},"canonical_url":"https://search.dev.ndltd.org/etd/cape-town/oai:open.uct.ac.za:11427/19813","repository":{"repo_id":"cape-town","name":"University of Cape Town","base_url":"https://open.uct.ac.za/oai/request"},"display":{"title":"Application of the transformation of 1,2,4-Trimethylbenzene to monitor the chemical vapour deposition of Tetraethoxysilane over ZSM-5","abstract":"The present work reports an improved chemical vapour deposition (CVD) technique using low temperature, tetraethoxysilane (TEOS) and repeated CVD-calcination cycles. This results in a better control of the external surface activity and the pore mouth size of ZSM-5. In search for effective characterisation tools and a model reaction which involves molecules which are critical in size relative to the size of the ZSM-5 channels, the transformation of 1,2,4-trimethylbenzene (1,2,4-TMB) was investigated with respect to the reaction network, the role of the micropore space and the response to CVD treatments and Silicalite I coating. A generalised interpretation of the effect of modifications of the external surface activity and the pore mouth size on activity and shape selectivity of zeolites is proposed.","abstract_html":"The present work reports an improved chemical vapour deposition (CVD) technique using low temperature, tetraethoxysilane (TEOS) and repeated CVD-calcination cycles. This results in a better control of the external surface activity and the pore mouth size of ZSM-5. In search for effective characterisation tools and a model reaction which involves molecules which are critical in size relative to the size of the ZSM-5 channels, the transformation of 1,2,4-trimethylbenzene (1,2,4-TMB) was investigated with respect to the reaction network, the role of the micropore space and the response to CVD treatments and Silicalite I coating. A generalised interpretation of the effect of modifications of the external surface activity and the pore mouth size on activity and shape selectivity of zeolites is proposed.","abstract_has_math":false,"creators":["Röger, Hans Peter"],"institution":"Department of Chemical Engineering","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Möller, Klaus","O'Connor, Cyril"],"committee_chairs":[],"committee_members":[],"year":1998,"date_issued":"1998","date_published":"1998","updated_at":"2026-07-22T22:22:52Z","subjects":[],"languages":["eng"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/11427/19813","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Möller, Klaus","O'Connor, Cyril"]},{"key":"dc:creator","label":"Author","values":["Röger, Hans Peter"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2016-05-24T09:13:46Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2016-05-24T09:13:46Z"]},{"key":"dc:date.issued","label":"Date","values":["1998"]},{"key":"dc:publisher.department","label":"Dc Publisher Department","values":["Department of Chemical Engineering"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["University of Cape Town"]},{"key":"dc:type","label":"Dc Type","values":["Doctoral Thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["Doctoral"]},{"key":"dc:type.qualificationname","label":"Dc Type Qualificationname","values":["PhD"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["eng"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/11427/19813"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["The present work reports an improved chemical vapour deposition (CVD) technique using low temperature, tetraethoxysilane (TEOS) and repeated CVD-calcination cycles. This results in a better control of the external surface activity and the pore mouth size of ZSM-5. In search for effective characterisation tools and a model reaction which involves molecules which are critical in size relative to the size of the ZSM-5 channels, the transformation of 1,2,4-trimethylbenzene (1,2,4-TMB) was investigated with respect to the reaction network, the role of the micropore space and the response to CVD treatments and Silicalite I coating. A generalised interpretation of the effect of modifications of the external surface activity and the pore mouth size on activity and shape selectivity of zeolites is proposed."]},{"key":"dc:title","label":"Title","values":["Application of the transformation of 1,2,4-Trimethylbenzene to monitor the chemical vapour deposition of Tetraethoxysilane over ZSM-5"]}]}],"canonical_facts":{"dc:contributor.advisor":["Möller, Klaus","O'Connor, Cyril"],"dc:creator":["Röger, Hans Peter"],"dc:date.accessioned":["2016-05-24T09:13:46Z"],"dc:date.available":["2016-05-24T09:13:46Z"],"dc:date.issued":["1998"],"dc:description.abstract":["The present work reports an improved chemical vapour deposition (CVD) technique using low temperature, tetraethoxysilane (TEOS) and repeated CVD-calcination cycles. This results in a better control of the external surface activity and the pore mouth size of ZSM-5. In search for effective characterisation tools and a model reaction which involves molecules which are critical in size relative to the size of the ZSM-5 channels, the transformation of 1,2,4-trimethylbenzene (1,2,4-TMB) was investigated with respect to the reaction network, the role of the micropore space and the response to CVD treatments and Silicalite I coating. 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