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Scholars Day 2007, Wednesday, April 11

Probing Solvation in Supercritical Fluids

Ionic liquids (ILs) and supercritical fluids (SCFs) are attractive media because of their potential uses in developing chemical processes that are environmentally friendly. Research has shown that most ILs are insoluble in bulk phase SCFs, in particular supercritical carbon dioxide (scCO2). We have studied the solvation of phosphonium ionic liquids in scCO2. For these experiments, several fluorescent probes were used to monitor the dissolution of the ILs in supercritical carbon dioxide by measuring intensity as a function of pressure and temperature. Of all the fluorophores used, PRODAN yielded the most interesting data. The emission spectra showed two distinct peaks whose peak intensities were observed to be strongly pressure dependent. We attribute the peak near 400 nm to solvation of PRODAN in scCO2 and the peak near 460 nm to PRODAN dissolved in IL/ scCO2. This talk will focus on the spectroscopic details of the solubility of ionic liquid in supercritical carbon dioxide, and the fluorophore dynamics in PIL/ scCO2.

Presenter: Kathryn Wieczorek (Undergraduate Student)
Topic: Chemistry
Location: 33 Hartwell
Time: 11 am (Session II)