Influence of the Water Content on the Structure and Physicochemical Properties of an Ionic Liquid and Its Li super(+) Mixture

The effect of water on the hydrophobic ionic liquid (IL) 1-n-butyl-2,3-dimethylimidazolium bis(trifluoromethanesulfonylimide) and its Li super(+) mixture was evaluated. The electrochemical stability, density, viscosity, and ionic conductivity were measured for both systems in different concentration...

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Bibliographic Details
Published in:The journal of physical chemistry. B 2013-07, Vol.117 (29), p.8782-8792-8782-8792
Main Authors: Martins, Vitor L, Nicolau, Bruno G, Urahata, Sergio M, Ribeiro, Mauro CC, Torresi, Roberto M
Format: Article
Language:English
Subjects:
Aggregates
Cations
Charge
Density
Dynamical systems
Dynamics
Ionic liquids
Molecular dynamics
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Summary:The effect of water on the hydrophobic ionic liquid (IL) 1-n-butyl-2,3-dimethylimidazolium bis(trifluoromethanesulfonylimide) and its Li super(+) mixture was evaluated. The electrochemical stability, density, viscosity, and ionic conductivity were measured for both systems in different concentrations of water. The presence of Li super(+) causes a large increase in the water absorption ability of the IL. The experimental results suggest a break of the interactions between Li super(+) and Tf sub(2)N super(-) anions in the strong aggregates formed in dried Li super(+) mixtures, modifying the size and physicochemical nature of these aggregates. It is also observed that the size of the ions aggregates with formal charge increases at high temperature and decreases the mobility of the charge carrier, explaining the break in the Walden rules at high temperature. Raman spectroscopy and molecular dynamic simulations show the structural change of these systems. In neat ILs, the water molecules interact mainly among each other, while in the Li super(+) mixtures, water interacts preferentially with the metallic cation, causing an important change in the aggregates present in this system.
ISSN:1520-6106
1520-5207
DOI:10.1021/jp312839z