{"id":{"repo_id":"cape-town","oai_identifier":"oai:open.uct.ac.za:11427/13518"},"canonical_url":"https://search.dev.ndltd.org/etd/cape-town/oai:open.uct.ac.za:11427/13518","repository":{"repo_id":"cape-town","name":"University of Cape Town","base_url":"https://open.uct.ac.za/oai/request"},"display":{"title":"Dimethyl N-Aryl phosphoramidates : structural effects on bonding and solvolytic reactivity","abstract":"The acid catalysed hydrolysis of a number of ring alkyl substituted dimethyl N-aryl phosphoramidates, (MeO)2P(0)NHAr, has been studied by measuring the rates of hyd~olysis with the aid of a UV spectrophotometer. These rates have been correlated with the pKa values of the corresponding ani I inium iOhs and the slope of this reactivitybasicity relationship for phosphoramidate with ortho substituents (6 = 0~85) is found to differ from that for substrates with meta and para substituents (S = 0,36). Determination of the thermodynamic parameters indicates that the entropy of activation is approximately constant for the substrates studied and the strongly negative values ~ -I -I (~S = 155,4 - 17,5 J mole K ) are consistent with an A2 type mechanism.","abstract_html":"The acid catalysed hydrolysis of a number of ring alkyl substituted dimethyl N-aryl phosphoramidates, (MeO)2P(0)NHAr, has been studied by measuring the rates of hyd~olysis with the aid of a UV spectrophotometer. These rates have been correlated with the pKa values of the corresponding ani I inium iOhs and the slope of this reactivitybasicity relationship for phosphoramidate with ortho substituents (6 = 0~85) is found to differ from that for substrates with meta and para substituents (S = 0,36). Determination of the thermodynamic parameters indicates that the entropy of activation is approximately constant for the substrates studied and the strongly negative values ~ -I -I (~S = 155,4 - 17,5 J mole K ) are consistent with an A2 type mechanism.","abstract_has_math":false,"creators":["Rijkmans, Bloys Peter"],"institution":"Department of Chemistry","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Modro, Tom A"],"committee_chairs":[],"committee_members":[],"year":1981,"date_issued":"1981","date_published":"1981","updated_at":"2026-07-22T22:23:26Z","subjects":[],"languages":["eng"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/11427/13518","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Modro, Tom A"]},{"key":"dc:creator","label":"Author","values":["Rijkmans, Bloys Peter"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2015-07-14T09:02:35Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2015-07-14T09:02:35Z"]},{"key":"dc:date.issued","label":"Date","values":["1981"]},{"key":"dc:publisher.department","label":"Dc Publisher Department","values":["Department of Chemistry"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["University of Cape Town"]},{"key":"dc:type","label":"Dc Type","values":["Master Thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["Masters"]},{"key":"dc:type.qualificationname","label":"Dc Type Qualificationname","values":["MSc"]}]},{"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/11427/13518"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Bibliography: p. 84-86."]},{"key":"dc:description.abstract","label":"Abstract","values":["The acid catalysed hydrolysis of a number of ring alkyl substituted dimethyl N-aryl phosphoramidates, (MeO)2P(0)NHAr, has been studied by measuring the rates of hyd~olysis with the aid of a UV spectrophotometer. These rates have been correlated with the pKa values of the corresponding ani I inium iOhs and the slope of this reactivitybasicity relationship for phosphoramidate with ortho substituents (6 = 0~85) is found to differ from that for substrates with meta and para substituents (S = 0,36). Determination of the thermodynamic parameters indicates that the entropy of activation is approximately constant for the substrates studied and the strongly negative values ~ -I -I (~S = 155,4 - 17,5 J mole K ) are consistent with an A2 type mechanism."]},{"key":"dc:title","label":"Title","values":["Dimethyl N-Aryl phosphoramidates : structural effects on bonding and solvolytic reactivity"]}]}],"canonical_facts":{"dc:contributor.advisor":["Modro, Tom A"],"dc:creator":["Rijkmans, Bloys Peter"],"dc:date.accessioned":["2015-07-14T09:02:35Z"],"dc:date.available":["2015-07-14T09:02:35Z"],"dc:date.issued":["1981"],"dc:description":["Bibliography: p. 84-86."],"dc:description.abstract":["The acid catalysed hydrolysis of a number of ring alkyl substituted dimethyl N-aryl phosphoramidates, (MeO)2P(0)NHAr, has been studied by measuring the rates of hyd~olysis with the aid of a UV spectrophotometer. These rates have been correlated with the pKa values of the corresponding ani I inium iOhs and the slope of this reactivitybasicity relationship for phosphoramidate with ortho substituents (6 = 0~85) is found to differ from that for substrates with meta and para substituents (S = 0,36). Determination of the thermodynamic parameters indicates that the entropy of activation is approximately constant for the substrates studied and the strongly negative values ~ -I -I (~S = 155,4 - 17,5 J mole K ) are consistent with an A2 type mechanism."],"dc:identifier.uri":["http://hdl.handle.net/11427/13518"],"dc:language.iso":["eng"],"dc:publisher.department":["Department of Chemistry"],"dc:publisher.institution":["University of Cape Town"],"dc:title":["Dimethyl N-Aryl phosphoramidates : structural effects on bonding and solvolytic reactivity"],"dc:type":["Master Thesis"],"dc:type.qualificationlevel":["Masters"],"dc:type.qualificationname":["MSc"]},"updated_at":"2026-07-22T22:23:26Z"}