The Aggregation Behavior of Short Chain Hydrophilic Ionic Liquids in Aqueous Solutions

Document Type : Research Article


Key Laboratory for Chemistry of Low-Dimensional Materials, Huaiyin Normal University, Huaian, 223300, CHINA


In this paper, aggregation behaviors of aqueous solutions of short chain hydrophilic Ionic Liquids (ILs), 1 – allyl - 3 - methylimidazolium chloride ([Amim]Cl), 1 - ethyl - 3 - methylimidazolium chloride ([Emim]Cl), 1 - butyl - 3 - methylimidazolium chloride ([Bmim]Cl), 1 - butyl - 3 - methylimidazolium tetrafluoroborate ([Bmim]BF4) were investigated using conductivity and laser light scattering. The measurements of conductivity and light scattering were conducted over the whole liquid range, and the Critical Aggregation Concentration (CAC) of aqueous ILs solution determined with the conductivity, was in the order of 2.35mol/L([Amim]Cl) > 2.32mol/L([Emim]Cl) > 2.29mol/L([Bmim]Cl) < 2.54mol/L([Bmim]BF4 ). The CAC vaule of [Bmim]BF4 determined with conductivity was consistent with the result of light scattering. In addition, we proposed aggregation model for illustrating the structural change in the aqueous ILs solutions.


Main Subjects

[1] Rogers R.D., Sedden K.R., Ionic Liquids-Solvents of the Future, Science, 302, p. 792 (2003).
[2] Welton T.,Room-Temperature Ionic Liquids: Solvents for Synthesis and Catalysis, Chem. Rev., 99, p. 2071 (1999).
[3] Chiappe C., Pieraccini D., Ionic Liquids: Solvent Properties and Organic Reactivity, J .Phys .Org. Chem., 18, p. 275 (2005).
[4] Kubisa P., Application of Ionic Liquids as Solvents for Polymerization Processes, Prog. Polym. Sci., 29, p. 3 (2004).
[5] Huddleston J.G., Willauer H.D., Swatloski R.P., Visser A.E., Rogers R.D., Room Temperature Ionic Liquids as Novel Media for ‘Clean’ Liquid-Liquid Extraction, Chem. Commun., 16, p. 1765 (1998).
[6] El Seoud O.A., Pires P.A.R., Abdel-Moghny T., Bastos E.L., Synthesis and Micellar Properties of Surface-active Ionic Liquids: 1-Alkyl-3-Methylimidazolium Chlorides, J. Colloid. Interface. Sci., 313, p. 296 (2007).
[7] Vanyur R., Biczok L., Miskolczy Z., Micelle Formation of 1-Alkyl-3-Methylimidazolium Bromide Ionic Liquids in Aqueous Solution, Colloids. Sur A, 299, p. 256 (2007).
[8] Baker G.A., Pandey S., Pandey S., Baker S.N., A New Class of Cationic Surfactants Inspired by
N-Alkyl-N-Methylpyrrolidinium Ionic Liquids, Analyst, 129, p. 890 (2004).
[9] Liu W.W., Zhao T.Y., Zhang Y.M., Wang H.P., Yu M.F., The Physical Properties of Aqueous Solution of Ionic Liquids [Bmim]BF4, J. Solution. Chem., 35, p. 1337 (2006).
[10] Wang H.Y., Wang J.J., Zhang S.B., Structural Effects of Anions and Cations on the Aggregation Behavior of Ionic Liquids in Aqueous Solutions. J. Phys. Chem. B, 112, p. 16682 (2008).
[11] Wang, H.Y., Feng, Q.Q., Wang, J.J.: Salt Effect on the Aggregation Behavior of 1-decyl-3-Methylimidazolium Bromide in Aqueous Solutions. J. Phys. Chem.114, p.1380 (2010)
[12] Chen, Y.J., Zhao, Y., Chen, J.: Aggregation Behavior of a Model Ionic Liquid Surfactant in Monosaccharide + Water Solutions. J. Colloid. Interface. Sci. 364, p. 388 (2011)
[13] Zhang, H.; Wu, J.; Zhang, J. 1-Allyl-3-Methylimidazolium Chloride Room Temperature Ionic Liquid: A New and Powerful Nonderivatizing Solvent for Cellulose. Macromolecules, 38, P. 8272 (2005)
[14] Schneider, S.; Drake, G.; Hall, L. Alkene- and Alkyne-Substituted Methylimidazolium Bromides: Structural Effects and Physical Properties. Z. Anorg. Allg. Chem. 633, p. 1701 (2007)
[15] Huddleston, J. G.; Visser, A. E.; Rogers, R. D. Characterization and Comparison of Hydrophilic and Hydrophobic Room Temperature Ionic Liquids Incorporating the Imidazolium Cation. Green. Chem, 3, p. 156 (2001)
[16] literature/ lit_TurboCorr.html.
[17] Wu, B., Liu, W.W., Zhang, Y.M., Wang, H.P.: Do We Understand the Recyclability of Ionic liquids. Chem. Eur. J, 15, p. 1804 (2009)
[18] Durand-Vidal, S., Jardat, M., Turq, P.: Determining the Radius and the Apparent Charge of a Micelle from Electrical Conductivity Measurements by Using a Transport Theory: Explicit Equations for Practical Use. J. Phys. Chem. B, 110, p. 15542 ( 2006)
[19] Wu, B., Zhang, Y.M., Wang, H.P.: Phase Behavior for Ternary Systems Composed of Ionic Liquid + Saccharides + Water. J. Phys.Chem.B, 112, p. 6426 (2008)
[20] Bowers, J., Butts, C.P., Martin P.J., Vergara-Gutierrez, M.C.: Aggregation Behavior of Aqueous Solutions of Ionic Liquids. Langmuir 20, p. 2191 (2004)
[21] Pdf
[22] Singh, T., Kumar, A.: Aggregation Behavior of Ionic Liquids in Aqueous Solutions: Effect of Alkyl Chain Length, Cations, and Anions. J. Phys. Chem. 111,    p.7843 (2007)
[23] Selimar, R R., Steven, B.: Influence of Water on the Surface of Hydrophilic and Hydrophobic Room Temperature Ionic Liquids. J. Am. Chem. Soc. 126, p. 11788 (2004).