Effect of Cationic and Anionic Chain Lengths on Volumetric, Transport, and Surface Properties of 1-Alkyl-3-methylimidazolium Alkylsulfate Ionic Liquids at (298.15 and 313.15) K

The effect of the alkyl chain of 1-alkyl-3-methylimidazolium alkylsulfate ([C(n)mim][CH3SO4] and [C(n)mim][C2H5SO4] ionic liquids (ILs) with n between 1 to 8) on density, viscosity, and surface tension has been experimentally determined at (298.15 and 313.15) K. In addition, the quantum-chemical COSMO-RS method is used to extend the analysis of the influence of sulfate alkyl length on density by screening [C(n)mim][CmH2m+1SO4] compounds with m between 1 and 8. COSMO-RS is also tested for the first time in the prediction of IL viscosities. Density and surface tension of the ILs studied decrease with the number of carbon atoms in the alkyl substituent of cation, whereas viscosity increases. All of these properties decrease as the temperature increases.