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Title: Structure and lifetimes in ionic liquids and their mixtures

Abstract

With the aid of molecular dynamics simulations, we study the structure and dynamics of different ionic liquid systems, with focus on hydrogen bond, ion pair and ion cage formation. To do so, we report here radial distribution functions, their number integrals, and various time–correlation functions, from which we extract well-defined lifetimes by means of the reactive flux formalism. We explore the influence of polarizable force fields vs. non-polarizable ones with downscaled charges (±0.8) for the example of 1-butyl-3-methylimidazolium bromide. Furthermore, we use 1-butyl-3-methylimidazolium trifluoromethanesulfonate to investigate the impact of temperature and mixing with water as well as with the chloride ionic liquid. Smaller coordination numbers, larger distances, and tremendously accelerated dynamics are observed when the polarizable force field is applied. The same trends are found with increasing temperature. Adding water decreases the ion–ion coordination numbers whereas the water–ion and water–water coordination is enhanced. A domain analysis reveals that the nonpolar parts of the ions are dispersed and when more water is added the water clusters increase in size. The dynamics accelerate in general upon addition of water. In the ionic liquid mixture, the coordination number around the cation changes between the two anions, but the number integrals of the cationmore » around the anions remain constant and the dynamics slow down with increasing content of the chloride ionic liquid.« less

Authors:
ORCiD logo [1];  [2];  [3]; ORCiD logo [2]; ORCiD logo [4]; ORCiD logo [3];  [5]; ORCiD logo [2]
  1. Univ. of Bonn (Germany). Mulliken Center for Theoretical Chemistry; Max Planck Inst. for Chemical Energy Conversion, Mülheim (Germany)
  2. Univ. of Bonn (Germany). Mulliken Center for Theoretical Chemistry
  3. Imperial College, London (United Kingdom)
  4. Martin-Luther-Univ. Halle-Wittenberg, Halle (Germany). Theoretical Chemistry
  5. Virginia Commonwealth Univ., Richmond, VA (United States). Dept. of Chemistry
Publication Date:
Research Org.:
Virginia Commonwealth Univ., Richmond, VA (United States); Univ. of Bonn (Germany)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Science Foundation (NSF); German Research Foundation (DFG)
OSTI Identifier:
1525961
Grant/Contract Number:  
SC0004406; CHE-1213814; SPP 1708; KI 768/15-1; Br 5494/1-1
Resource Type:
Accepted Manuscript
Journal Name:
Faraday Discussions
Additional Journal Information:
Journal Volume: 206; Journal ID: ISSN 1359-6640
Publisher:
Royal Society of Chemistry
Country of Publication:
United States
Language:
English

Citation Formats

Gehrke, Sascha, von Domaros, Michael, Clark, Ryan, Hollóczki, Oldamur, Brehm, Martin, Welton, Tom, Luzar, Alenka, and Kirchner, Barbara. Structure and lifetimes in ionic liquids and their mixtures. United States: N. p., 2017. Web. doi:10.1039/c7fd00166e.
Gehrke, Sascha, von Domaros, Michael, Clark, Ryan, Hollóczki, Oldamur, Brehm, Martin, Welton, Tom, Luzar, Alenka, & Kirchner, Barbara. Structure and lifetimes in ionic liquids and their mixtures. United States. doi:10.1039/c7fd00166e.
Gehrke, Sascha, von Domaros, Michael, Clark, Ryan, Hollóczki, Oldamur, Brehm, Martin, Welton, Tom, Luzar, Alenka, and Kirchner, Barbara. Tue . "Structure and lifetimes in ionic liquids and their mixtures". United States. doi:10.1039/c7fd00166e. https://www.osti.gov/servlets/purl/1525961.
@article{osti_1525961,
title = {Structure and lifetimes in ionic liquids and their mixtures},
author = {Gehrke, Sascha and von Domaros, Michael and Clark, Ryan and Hollóczki, Oldamur and Brehm, Martin and Welton, Tom and Luzar, Alenka and Kirchner, Barbara},
abstractNote = {With the aid of molecular dynamics simulations, we study the structure and dynamics of different ionic liquid systems, with focus on hydrogen bond, ion pair and ion cage formation. To do so, we report here radial distribution functions, their number integrals, and various time–correlation functions, from which we extract well-defined lifetimes by means of the reactive flux formalism. We explore the influence of polarizable force fields vs. non-polarizable ones with downscaled charges (±0.8) for the example of 1-butyl-3-methylimidazolium bromide. Furthermore, we use 1-butyl-3-methylimidazolium trifluoromethanesulfonate to investigate the impact of temperature and mixing with water as well as with the chloride ionic liquid. Smaller coordination numbers, larger distances, and tremendously accelerated dynamics are observed when the polarizable force field is applied. The same trends are found with increasing temperature. Adding water decreases the ion–ion coordination numbers whereas the water–ion and water–water coordination is enhanced. A domain analysis reveals that the nonpolar parts of the ions are dispersed and when more water is added the water clusters increase in size. The dynamics accelerate in general upon addition of water. In the ionic liquid mixture, the coordination number around the cation changes between the two anions, but the number integrals of the cation around the anions remain constant and the dynamics slow down with increasing content of the chloride ionic liquid.},
doi = {10.1039/c7fd00166e},
journal = {Faraday Discussions},
number = ,
volume = 206,
place = {United States},
year = {2017},
month = {7}
}

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Works referenced in this record:

Room-Temperature Ionic Liquids. Solvents for Synthesis and Catalysis
journal, August 1999

  • Welton, Thomas
  • Chemical Reviews, Vol. 99, Issue 8, p. 2071-2084
  • DOI: 10.1021/cr980032t