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Interactions of ionic liquids and water
Lindsay E Ficke1, Joan F Brennecke
1Department of Chemical and Biomolecular Engineering, University of Notre Dame, 182 Fitzpatrick Hall, Notre Dame, Indiana 46556, USA.
The Journal of Physical Chemistry. B
|August 13, 2010
Summary
Ionic liquid-water interactions were studied using excess enthalpies and CHELPG atomic charges. These analyses reveal key insights into the specific interactions between ions and water molecules in solution.
Area of Science:
- Physical Chemistry
- Solution Chemistry
- Ionic Liquids
Background:
- Ionic liquids (ILs) are versatile solvents with tunable properties.
- Understanding IL-water interactions is crucial for their application in various chemical processes.
Purpose of the Study:
- To investigate the interactions between ionic liquids and water.
- To correlate experimental excess enthalpies with calculated atomic charges.
Main Methods:
- Excess enthalpies were measured using calorimetry (Setaram C80) across a range of temperatures (313.15–348.15 K) and compositions.
- CHELPG atomic charges of cations and anions were calculated using the Gaussian 03 program.
- Investigated ILs included 1-ethyl-3-methylimidazolium and 1-(2-hydroxyethyl)-3-methylimidazolium cations with various anions.
Main Results:
- Experimental excess enthalpies showed clear trends with varying IL structures.
- Calculated CHELPG atomic charges correlated well with the observed excess enthalpy data.
- Insights were gained into cation/water, anion/water, and cation/anion interactions.
Conclusions:
- CHELPG atomic charges provide a valuable tool for understanding and predicting IL-water interactions.
- Systematic variation of anion substituents influences the energetic contributions to mixing.
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