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

Abstract

Densities (F), viscosities (η), and isobaric heat molar capacities (C p ) of binary mixtures containing imidazolium octanoate, [Im][C 7 CO 2 ], 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, ∆η, of imidazolium octanoate solutions were then deduced from the experimental results, as well as apparent molar volumes, V φi , and partial molar volumes, V j m,i . Results are discussed according to the nature of the interaction between the PIL and the molecules and the effect of temperature. The excess Gibbs energies of activation of viscous flow (∆G *E ) for these systems were then calculated at 298.15 K. The excess isobaric heat capacities, C p E , of binary ([Im][C 7 CO 2 ] + 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.

Viscosity of binary mixtures of 1-ethyl-3-methylimidazolium tetrafluoroborate ionic liquid with four organic solvents

“…The [38] [38] a Standard uncertainties, u, are: u(T) = 0.01 K, u(p) = 0.002 MPa, the relative standard uncertainty, u r , is u r (η) = 5%.…”

Molar heat capacities of the mixture {1,8-cineole + ethanol} at several temperatures and atmospheric pressure

“…Densities of water [17] and ethanol [14] for applying equation (1) heat capacities, being higher than those of Zábranský et al [18] and Anouti et al [20] and lower than those of García-Miaja et al [19] and Vega-Maza et al [22]. The deviations from the values calculated through the polynomial of Zábranský et al [18], which are likely the best ones, range from 0.2% at the higher temperature to 0.4% at the lower one.…”

“…From this comparison, it can be concluded that the equipment has a good performance. [18] () García-Miaja et al [19]; (▼) Anouti et al [20]; () Tripathi [21]; () Vega-Maza et al …”

Aqueous solutions of ionic liquids. Description of osmotic coefficients within the Binding Mean Spherical Approximation

“…1 In relation to industrial applications of these new compounds, a big effort is currently done to gather and describe experimental thermodynamics data of either pure ionic liquids or of mixtures thereof with aqueous or non-aqueous solutions. [2][3][4][5][6] Few data for osmotic or activity coefficients of aqueous ionic liquids solutions have been reported [7][8][9][10][11][12][13][14][15] and most thermodynamics electrolyte models such as Pitzer, NRTL or e-NRTL models, or more recently COSMO-SAC 16 , have been used to describe these thermodynamic quantities. Even though models were found to describe successfully the binary systems composed of an ionic liquid and a solvent, the parameters within these models are semi-empirical, yielding potential extrapolations to the description of mixtures difficult -if not impossible -and rather unreliable.…”