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Benzophenone as a Probe of Local Cosolvent Effects in Supercritical Ethane
The n → π* shift of benzophenone has been used to quantify solute−cosolvent interactions in supercritical ethane. Dilute solutions of benzophenone in cosolvent/supercritical ethane mixtures were studied at 35 °C from 50 to 100 bar over a range of cosolvent concentrations. The following cosolvents we...
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Published in: | Industrial & engineering chemistry research 1997-03, Vol.36 (3), p.854-868 |
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Main Authors: | , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | The n → π* shift of benzophenone has been used to quantify solute−cosolvent interactions in supercritical ethane. Dilute solutions of benzophenone in cosolvent/supercritical ethane mixtures were studied at 35 °C from 50 to 100 bar over a range of cosolvent concentrations. The following cosolvents were chosen for investigation on the basis of their varying abilities to interact with benzophenone: 2,2,2-trifluoroethanol, ethanol, chloroform, propionitrile, 1,2-dibromoethane, and 1,1,1-trichloroethane. In the supercritical systems investigated here, hydrogen bonding of protic cosolvents to the carbonyl oxygen of benzophenone is the primary mechanism of the n → π* shift. The results of this investigation are consistent with a chemical−physical interpretation of cosolvent effects in supercritical fluids in the presence of strong specific solute−cosolvent interactions. The experimental results for the ethane/TFE/benzophenone system were analyzed by using integral equations in order to study the assumptions of the chemical−physical model. This combination of spectroscopic data with radial distribution function models provides a powerful tool for understanding cosolvent effects. |
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ISSN: | 0888-5885 1520-5045 |
DOI: | 10.1021/ie9600809 |