Professor Brennecke's research interests are in the areas of supercritical fluid technology and thermodynamics. Of particular interest is the use of supercritical carbon dioxide and supercritical water as environmentally benign solvents for extractions, separations and reactions. Current research projects investigate the solvent effect on reactions in supercritical fluids, use of spectroscopy and integral equation theory to determine the local environment around dissolved solutes, and measurement and modeling of high pressure phase behavior. Her group is also interested in experimental and theoretical studies of preferential solvation in liquid mixtures.
Supercritical fluids exhibit some very dramatic and attractive solvent properties. Because they are compressible, their density, and subsequently their solvating power, can be controlled with small changes in temperature and pressure. They are currently used for the decaffeination of coffee and the extraction of natural flavors and oils. Dr. Brennecke's group is particularly interested in the use of supercritical fluids, such as carbon dioxide, as solvents to replace more traditional, but more environmentally hazardous, solvents for reactions. Towards this end her group has focused on the use of spectroscopic methods, such as laser flash photolysis, pulse radiolysis and time-resolved fluorescence, to study the solvent and pressure effect on reactions kinetics in supercritical fluids. Her group is also interested in the use of integral equation theory to gain insight into how the microscopic solvation of solutes affects the thermodynamic properties of a supercritical fluid mixture and on measuring and modeling high pressure phase behavior. The measurement, modeling and development of more reliable computational techniques for high pressure phase behavior of CO2-based reaction systems is the focus of a project being done in collaboration with Professor Stadtherr. Finally, Dr. Brennecke's research has included the use of spectroscopic probes to measure preferential solvation in liquid mixtures as a means of evaluating excess Gibb's free energy models that are based on the idea of local compositions being significantly different than the bulk.
