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Salting out near the critical point.
1Institute of Theoretical Science, Department of Chemistry, University of Oregon, Eugene, Oregon 97403, USA.
The Journal of Physical Chemistry. B
|June 1, 2007
Summary
The salting out effect for solid solutes intensifies near a solvent's critical point. This phenomenon, driven by solvent compressibility, is significant and predictable using fluctuation theory.
Area of Science:
- Physical Chemistry
- Thermodynamics
- Solution Chemistry
Background:
- Salting out is a phenomenon where the solubility of a solute decreases due to the addition of a salting-out agent.
- The critical point of a solvent is a unique thermodynamic state where distinct liquid and gas phases cease to exist.
Purpose of the Study:
- To investigate the salting out of solid solutes near the critical point of a solvent.
- To analyze the behavior of the salting out coefficient in relation to solvent properties.
Main Methods:
- Utilizing results from a previous study on fluctuation theory of salting out.
- Analyzing the salting out coefficient at infinite dilution of cosolvent.
Main Results:
- The salting out coefficient at infinite dilution is approximately proportional to solvent compressibility.
- Salting out effects become significantly large near the solvent's critical point.
- The infinite dilution approximation is valid over a considerable concentration range away from the critical point.
Conclusions:
- Solvent compressibility is a key factor driving the salting out effect near critical points.
- Fluctuation theory provides a framework for understanding enhanced salting out phenomena.
- The study highlights the unique behavior of solutions approaching critical conditions.
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