Intermolecular interactions in supercritical fluid solutions from fluorescence spectroscopy

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.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Engineering, Chemical

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

1989

Author dc:creator

• Brennecke, Joan F.

Contributors dc:contributor

• Eckert, Charles A.

• Engineering, Chemical

Statement dc:rights

• Copyright 1989 Brennecke, Joan F.

Language dc:language

eng

Identifier

AAI9010810
(UMI)AAI9010810

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/23786