Characterization and Kinetics of Microheterogenities in Ionic Liquids

• Applicant: Dr. Bernd Rathke
• Subject Area: Technical Thermodynamics
• Term: from 2008 to 2014
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 90929230

• Final Report Year: 2015

Final Report Abstract

Structure and dynamics of the class of ionic liquids 1-alkyl-3-methylimidazolium (bistrifluoromethylsulfonylamide, CxmimNtf2) were investigated on a mesoscopic scale by static and dynamic light scattering at ambient and elevated pressure. The experiments covered the temperature range of 288 – 423 K. It was found, that structural changes occur on very long time scales of the order of 10^5 – 10^6 seconds. In some cases hints on non ergodicity were observed, by long term temperature treatment structural ordering can be induced. A long term annealing of the liquids changes the microscopic ordering, after sufficiently long time it vanishes. Similar long term kinetics is also present in binary solutions of ionic liquids, partially superimposed by critical phenomena. For such investigations the determination of the underlying phase behavior is mandatory. Within the frame of the project a comprehensive characterization of the binary mixtures of CxmimNtf2 (1 ≤x ≤12) and n-alkyl alcohols CnOH (2 ≤ n ≤ 20) has been performed.

Publications

• Journal of Chemical and Engineering Data 56 (2011) 1330
  V.R. Vale, B. Rathke, S. Will, W. Schroer
  
• Journal of Chemical and Engineering Data 56 (2011) 4829
  V.R. Vale, B. Rathke, S. Will, W. Schroer
  
• Chemphyschem 13 (2012) 1860
  V.R. Vale, S. Will, W. Schroer, B. Rathke
  
• Journal of Chemical and Engineering Data 59 (2014) 225
  X.W. Shao, W. Schroer, B. Rathke