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Solvatochromism: a dielectric continuum model applied to supercritical fluids

Journal Article · · J. Phys. Chem.; (United States)
DOI:https://doi.org/10.1021/j100312a050· OSTI ID:5477672

The solvatochromic behavior of nonpolar supercritical fluids, in terms of the ..pi..* Kamlet and Taft polarity/polarizability parameter, is compared to the McRae-Bayliss model. A break in the plot of ..pi..* against the Onsager reaction field (F/sub 0/) is seen for the fluids studied at low reaction field values (low densities). The relationship between ..pi..* and the Onsager reaction field (F/sub 0/) shows two regions of nearly linear behavior. The transition from the low-density region to higher density region, where a smaller dependence of ..pi..* upon (F/sub 0/) is observed, is tentatively attributed to extensive solvent clustering about the solute. This hypothesis is supported by the behavior previously observed for the partial molar volume of the solute in the fluid anti v/sub 2/ infinity as a function of pressure. The rapid change in anti v/sub 2/ infinity is also shown to occur in the same region where the solvatochromic behavior of the fluid changes and the solute's solubility increases dramatically.

Research Organization:
Pacific Northwest Lab., Richland, WA
DOE Contract Number:
AC06-76RL01830
OSTI ID:
5477672
Journal Information:
J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 92:1; ISSN JPCHA
Country of Publication:
United States
Language:
English