Properties of pure 1-methylimidazolium acetate ionic liquid and its binary mixtures with alcohols

Densities and viscosities of the pure ionic liquid 1-methylimidazolium acetate ([Mim]Ac) and its binary mixtures with methanol, ethanol, 1-propanol, and 1-butanol were measured at temperature ranging from T = (293.15 to 313.15) K. The thermal expansion coefficient, molecular volume, standard entropy, and lattice energy of [Mim]Ac were deduced from the experimental density results. A simple linear equation was used to correlate the variation of viscosity of [Mim]Ac with temperature. Excess molar volumes V-E and viscosity deviations Delta eta for the binary mixtures at above mentioned temperature were calculated and fitted to the Redlich-Kister equation with satisfactory results. Excess molar volumes for {[Mim]Ac + 1-butanol} mixture have an S shape, while those for other mixtures have a negative deviation from ideal behaviour over the entire mole fraction range. Viscosity deviations are all negative deviation for {[Mim]Ac + alcohol} mixtures. The results were interpreted in terms of interactions and structural factors of binary mixtures. (C) 2012 Elsevier Ltd. All rights reserved.