Viscosity of Typical Room-Temperature Ionic Liquids: A Critical Review

Abstract

Experimental data on viscosity of typical ionic liquids in the liquid state were compiled and critically evaluated. The compilation contains data for 268 ionic liquids from 215 literature references and covers the period from 1998 through the end of December 2018. Equations for corrections of influences of contamination water and residual Cl− on viscosities of a series of typical ionic liquids are established. The influences of experimental methodology and the impurities (i.e., contamination water and residual halide ions) of the samples used on the reported viscosities of these typical ionic liquids are critically evaluated or quantitatively corrected, and the viscosities for these “pure” ionic liquids are recommended. The parameters of the Vogel–Fulcher–Tammann equation for temperature dependence of the recommended viscosities of these ionic liquids were reported. The effects of ionic structures on the viscosity of ionic liquids are presented.

Thermal Stability of Ionic Liquids: Current Status and Prospects for Future Development

“…Ionic liquids (ILs) are molten salts at room temperature composed of organic cations and organic/inorganic anions [1,2]. ILs have been described as "designer solvents" because their physicochemical property can be regulated or tailor-made by changing their constituents or the structures of the pairs of the ions [3][4][5]. Previous research has proved that ILs have many advantages, including non-volatility, non-flammability, high thermal and chemical stability, wide electrochemical window, tunable miscibility, and good extraction capability, which are not attained for the volatile organic solvents [6][7][8].…”

New chemistry for enhanced carbon capture: beyond ammonium carbamates

“…13,28 In addition, the viscosities of ionic liquids are relatively high and tend to increase upon CO2 adsorption (in some cases up to 200-fold), which represents a significant process challenge. 28,54 While molecular engineering allows access to CO2-loaded ILs with viscosities as low as 650 mPa•s, 55 these values are still significantly higher than CO2-loaded 30% aqueous monoethanolamine solution (4 mPa•s). 56 Last, the CO2/N2 absorption selectivities, kinetics, desorption conditions, and long-term cycling stabilities of ILs remain poorly characterized in many cases.…”

Soft Electronics Based on Liquid Conductors

“…The leading theory suggests that the change of electrical conductivity is the result of temperature-initiated changes of density and viscosity. [60][61][62] The charge transport in ionic liquids is theoretically and experimentally proposed to be a result of hopping of dissociated ions. The increase of temperature reduces the interaction of ions, which in turn, facilitates their hopping efficiency and further enhances the electrical conductivity.…”