Investigation on physical and electrochemical properties of three imidazolium based ionic liquids (1-hexyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide and 1-butyl-3-methylimidazolium methylsulfate)

Three types of imidazolium based ionic liquids, 1-hexyl-3-methylimidazolium tetrafluoroborate [BE]), 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([EMIM][NTf2]) and 1-butyl-3-methylimidazolium methylsulfate ([BMIM][MeSO4]) were prepared and a variety of their fundamental properties such as kinematic (nu) and dynamic (eta) viscosities, thermal stability, surface tension (sigma), refractive index (n(D)), pH and density (rho) were investigated as a function of temperature. The coefficients of thermal expansion (alpha(p)) of the pure liquids were also calculated from the experimental values of the density at different temperatures. Electrochemical studies of these pure fluids as media were also studied at screen printed glassy carbon electrode (SP-GCE). The measurements were performed on a single drop of ionic liquids at surface of a screen-printed three electrode cell. The results showed an ideal wide range of potential windows for studies of electrochemical behavior of some species such as hydrogen sulfide and thiols in the lipophilic and hydrophilic ionic liquids. These properties were studied for special purposes such as development of electroanalytical methods for trace determination of organosulfur compounds in petroleum and its products. (C) 2012 Elsevier B.V. All rights reserved.