Density, transport properties and electrochemical potential windows for the 2-hydroxy-N,N,N-trimethylethanaminium chlorides based ionic liquids at several temperatures

Abstract

The densities and transport properties of 2-hydroxy-N,N,N-trimethylethanaminium chlorides (choline chloride) based ionic liquids (ILs) were measured as a function of temperature in the range 298.15–353.15K. Three binary mixtures (1:1 mole ratio) of choline chloride with ethylene glycol, triethanolamine and oxalic acid respectively, were prepared and characterized. Correlations for the temperature dependence of the measured properties have been made and discussed in the terms of Arrhenius theory. Other important properties, such as isothermal compressibility, molecular volume, lattice energy, heat capacity, molar Gibbs energy, enthalpy and entropy of activation of viscous flow were derived for the studied ILs using the experimental data. The relationship between molar conductivity and viscosity were determined by the fractional Walden rule, which shows excellent linear behavior; however, the average slope is far from unity. The electrochemical potential windows of ILs were also determined.