Volumetric Properties, Viscosities, and Isobaric Heat Capacities of Imidazolium Octanoate Protic Ionic Liquid in Molecular Solvents

Densities (rho), viscosities (eta), and isobaric heat molar capacities (C-p) of binary mixtures containing imidazolium octanoate, [Im][C7CO2], a protic ionic liquid (PIL), with four molecular solvents, water, acetonitrile, ethanol, and 1-octanol, are determined as a function of temperature from (298.15 to 323.15) K and within the whole composition range at atmospheric pressure. Excess molar volumes, V-E, excess molar heat capacities, C-p(E), and the deviation from additivity rules of viscosities, Delta eta, of imidazolium octanoate solutions were then deduced from the experimental results, as well as apparent molar volumes, V-phi i and partial molar volumes, (V) over bar (m,l). Results are discussed according to the nature of the interaction between the Pa, and the molecules and the effect of temperature. The excess Gibbs energies of activation of viscous flow (Delta G*(E)) for these systems were then calculated at 298.15 K. The excess isobaric heat capacities, C-p(E), of binary ([Im][C7CO2] + solvent) systems, depend also of the nature of the molecular solvent in mixture. The excess properties were then correlated, at each temperature, as a function of composition by a Redlich-Kister-type equation. Finally results have been discussed in terms of molecular interactions and molecular structures in these binary mixtures, and thermodynamic properties of investigated binary mixtures were then compared to literature values together to investigate the impact of the nature of the solvent on these reported properties.