Interactions between water and 1-butyl-1-methylpyrrolidinium ionic liquids

J Chem Phys. 2015 Aug 14;143(6):064503. doi: 10.1063/1.4928065.

Abstract

We report experimental results on the diffusivity of water in two ionic liquids obtained using the pulsed-gradient spin-echo NMR method. Both ionic liquids have the same cation, 1-butyl-1-methylpyrrolidinium, but different trifluoromethyl-containing anions. One has a strongly hydrophobic anion, bis(trifluoromethylsulfonyl)amide, while the second has a hydrophilic anion, trifluoromethylsulfonate. Transport of water in these ionic liquids is much faster than would be predicted from hydrodynamic laws, indicating that the neutral water molecules experience a very different friction than the anions and cations at the molecular level. Temperature-dependent viscosities, conductivities, and densities are reported as a function of water concentration to further analyze the properties of the ionic liquid-water mixtures. These results on the properties of water in ionic liquids should be of interest to researchers in diverse areas ranging from separations, solubilizing biomass and energy technologies.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amides / chemistry
  • Anions / chemistry
  • Cations / chemistry
  • Diffusion
  • Friction
  • Hydrodynamics
  • Hydrophobic and Hydrophilic Interactions
  • Ionic Liquids / chemistry*
  • Onium Compounds / chemistry*
  • Proton Magnetic Resonance Spectroscopy
  • Pyrrolidines / chemistry*
  • Temperature
  • Viscosity
  • Water / chemistry*

Substances

  • Amides
  • Anions
  • Cations
  • Ionic Liquids
  • Onium Compounds
  • Pyrrolidines
  • Water
  • 1-butyl-1-methylpyrrolidinium