Volumetric and Viscosity Properties for the Binary Mixtures of 1-Octyl-3-methylimidazolium Tetrafluoroborate with Butanone or Alkyl Acetates

Abstract

In this work, densities and viscosities for the binary mixtures of 1-octyl-3-methylimidazolium tetrafluoroborate, [C8mim][BF4], with butanone, methyl acetate, ethyl acetate, propyl acetate and butyl acetate have been determined at 298.15 K. These data were used to calculate the excess molar volumes \( V_{m}^{\text{E}} \) and the viscosity deviations (lnη)E for the mixtures. It is shown that values of \( V_{m}^{\text{E}} \) are negative, while those of (lnη)E are positive in the whole concentration range. The \( V_{m}^{\text{E}} \) values show their minimum at the composition of xIL ≈ 0.3, and the (lnη)E values exhibit a maximum at the same mole fraction. For the binary systems, the absolute values of \( V_{m}^{\text{E}} \) decrease in the order: butanone > methyl acetate > ethyl acetate > propyl acetate > butyl acetate, whereas those of (lnη)E decrease in the order: methyl acetate > ethyl acetate > propyl acetate > butyl acetate > butanone. The results are discussed in terms of the ion–dipole interactions between cations of the ionic liquid and the organic molecules and hydrogen bonding interactions between anions of the ionic liquid and the organic compounds.