{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/23786"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/23786","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Intermolecular interactions in supercritical fluid solutions from fluorescence spectroscopy","abstract":"Much of the unusual behavior in supercritical fluids (SCF's), including enhanced solubilities, synergistic effects of mixed solutes, and entrainer effects, may be explained by a region around the solute that has a higher density than the bulk. We present a new technique to investigae SCF's using fluorescence spectroscopy to probe the local interactions. In contrast to thermodynamic measurements, this technique determines the strength of interactions on a molecular scale, which is important in the development of more accurate thermodynamic models. For pyrene, naphthalene, dibenzofuran and carbazole in SCF CO$\\sb2$, C$\\sb2$H$\\sb4$ and CF$\\sb3$H, the results indicate stronger solute/solvent interactions near the critical point and local densities that are liquid-like, even when the bulk density is quite low. We also present excimer fluorescence data that emphasize the importance of solute/solute interactions in dilute supercritical fluid solutions. Finally, results from exciplex fluorescence studies of a solute/SCF/entrainer system indicate a dramatic solvent effect on the photophysical kinetics.","abstract_html":"Much of the unusual behavior in supercritical fluids (SCF's), including enhanced solubilities, synergistic effects of mixed solutes, and entrainer effects, may be explained by a region around the solute that has a higher density than the bulk. We present a new technique to investigae SCF's using fluorescence spectroscopy to probe the local interactions. In contrast to thermodynamic measurements, this technique determines the strength of interactions on a molecular scale, which is important in the development of more accurate thermodynamic models. For pyrene, naphthalene, dibenzofuran and carbazole in SCF CO$\\sb2$, C$\\sb2$H$\\sb4$ and CF$\\sb3$H, the results indicate stronger solute/solvent interactions near the critical point and local densities that are liquid-like, even when the bulk density is quite low. We also present excimer fluorescence data that emphasize the importance of solute/solute interactions in dilute supercritical fluid solutions. Finally, results from exciplex fluorescence studies of a solute/SCF/entrainer system indicate a dramatic solvent effect on the photophysical kinetics.","abstract_has_math":true,"creators":["Brennecke, Joan F."],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Engineering, Chemical","degree_department":null,"school":null,"contributors":["Eckert, Charles A."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":1989,"date_issued":"1989","date_published":"1989","updated_at":"2026-07-22T22:25:22Z","subjects":["Engineering, Chemical"],"languages":["eng"],"rights":["Copyright 1989 Brennecke, Joan F."],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["AAI9010810","(UMI)AAI9010810"],"render_values":[{"text":"AAI9010810","href":null,"code":true},{"text":"(UMI)AAI9010810","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/23786","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Eckert, Charles A."]},{"key":"dc:creator","label":"Author","values":["Brennecke, Joan F."]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["1989","2011-05-07T14:27:00Z","10000-01-01"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Engineering, Chemical"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Engineering, Chemical"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 1989 Brennecke, Joan F."]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["AAI9010810","(UMI)AAI9010810","http://hdl.handle.net/2142/23786"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Much of the unusual behavior in supercritical fluids (SCF's), including enhanced solubilities, synergistic effects of mixed solutes, and entrainer effects, may be explained by a region around the solute that has a higher density than the bulk. We present a new technique to investigae SCF's using fluorescence spectroscopy to probe the local interactions. In contrast to thermodynamic measurements, this technique determines the strength of interactions on a molecular scale, which is important in the development of more accurate thermodynamic models. For pyrene, naphthalene, dibenzofuran and carbazole in SCF CO$\\sb2$, C$\\sb2$H$\\sb4$ and CF$\\sb3$H, the results indicate stronger solute/solvent interactions near the critical point and local densities that are liquid-like, even when the bulk density is quite low. We also present excimer fluorescence data that emphasize the importance of solute/solute interactions in dilute supercritical fluid solutions. Finally, results from exciplex fluorescence studies of a solute/SCF/entrainer system indicate a dramatic solvent effect on the photophysical kinetics.","Made available in DSpace on 2011-05-07T14:27:00Z (GMT). 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We present a new technique to investigae SCF's using fluorescence spectroscopy to probe the local interactions. In contrast to thermodynamic measurements, this technique determines the strength of interactions on a molecular scale, which is important in the development of more accurate thermodynamic models. For pyrene, naphthalene, dibenzofuran and carbazole in SCF CO$\\sb2$, C$\\sb2$H$\\sb4$ and CF$\\sb3$H, the results indicate stronger solute/solvent interactions near the critical point and local densities that are liquid-like, even when the bulk density is quite low. We also present excimer fluorescence data that emphasize the importance of solute/solute interactions in dilute supercritical fluid solutions. Finally, results from exciplex fluorescence studies of a solute/SCF/entrainer system indicate a dramatic solvent effect on the photophysical kinetics.","Made available in DSpace on 2011-05-07T14:27:00Z (GMT). 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