Density and viscosity of three (2,2,2-trifluoroethanol + 1-butyl-3-methylimidazolium) ionic liquid binary systems

• Densities and viscosities from 278.15 to 333.15 K are reported for three binary (2,2,2-trifluoroethanol + an IL) systems.
• TFE + [bmim][BF4] system presents positive VE values except for the highest mole fractions of TFE, at the highest temperatures.
• TFE + [bmim][PF6] presents negative VE values except at the low TFE mole fractions for the lowest temperatures.
• TFE + [bmim][NTf2] presents negative VE values for all the mole fractions and temperatures studied.
• The three systems present negative viscosity deviations becoming less negative with increasing temperature.

Densities and viscosities were determined for binary mixtures of 2,2,2-trifluoroethanol (TFE) and 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]), 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]) or 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([bmim][NTf2]) over the entire range of composition. The experimental measurements were carried out at temperatures ranging from 278.15 K to 333.15 K, at atmospheric pressure. The densities and viscosities of the pure ionic liquids and their mixtures with TFE were described successfully by an empirical third-order polynomial and by the Vogel–Fulcher–Tammann equation, respectively. In addition, excess molar volumes and viscosity deviations were determined from densities and viscosities of mixtures, respectively, and fitted by using the Redlich–Kister equation.