Viscosity and relative viscosity of hydrophobic imidazolium type ionic liquids with dimethyl carbonate

The viscosity of four dilution solution systems was determined for ionic liquids (ILs) with Dimethyl Carbonate (DMC) at lower concentration from 288.15 K to 313.15 K. The ILs include 1-ethyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([C2mim][NTf2]), 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([C4mim][NTf2]), 1-ethyl-2,3-dimethylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([C2mmim][NTf2]), and 1-butyl-2,3-dimethylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([C4mmim][NTf2]). The viscosities of systems have been discussed at studied concentration from 288.15 to 313.15 K. The temperature dependence on viscosities was fitted according to the Vogel-Fulcher-Tammann equation. The activation energies for viscous flow have been obtained from Arrhenius equation at different concentration range. The relative viscosities (ηr) were also calculated and analyzed according to the Jones–Dole equation at different molar concentration ranges. The slopes of the parameter, B-coefficient/dm3·mol−1, dependence on temperature, T/K have also been discussed according to the methyl and methylene groups introduction. The effects of methyl or methylene group introduction on ILs cation have also been discussed to solute–solute or solute–solvent interactions.