Heat Capacity, Excess Molar Volumes and Viscosity Deviation of Binary Systems of N-octylisoquinolinium bis{(trifluoromethyl)sulfonyl}imide Ionic Liquid

Abstract

Abstract Heat capacities were determined for two binary systems {N-octylisoquinolinium bis{(trifluoromethyl)sulfonyl} imide, ([C8iQuin][NTf2]) + benzene, or butan-1-ol} from (288.15 to 388.15) K. Density and viscosity were determined for four binary mixtures containing {[C8iQuin][NTf2]) + benzene, or toluene, or thiophene or pyridine} at six temperatures (298.15, 308.15, 318.15, 328.15, 338.15 and 348.15) K, ambient pressure, and covering the entire composition range. The influence of temperature and composition was discussed. As usually the heat capacity increases with an increase of the ionic liquid concentration. The molar heat capacities, densities and viscosities were correlated with suitable equations. The excess molar heat capacities, Δ C p, the excess molar volumes, V m E and dynamic viscosity deviations, Δη were described by the Redlich–Kister polynomial expansion. The Δ C p was negative for benzene and S-shaped for butan-1-ol, the V m E and Δη were low and negative. From the experimental values, the volume expansivity and the excess volume expansivity was calculated. The obtained results indicate that ionic liquid interactions with aromatic hydrocarbons are strong dependent on the packing effects and π–π interactions.