Journal of Solution Chemistry

, Volume 44, Issue 7, pp 1518–1528 | Cite as

Ionic Liquids: Additives for Manipulating the Nucleophilicity

  • Mudasir Ahmad Rather
  • Ghulam Mohammad Rather
  • Sarwar Ahmad Pandit
  • Sajad Ahmad Bhat
  • Khaliquz Zaman Khan
  • Mohsin Ahmad Bhat


Kinetic investigations of the SN2 reaction at the sulfur atom of p-toluenesulfonyl chloride with sodium azide in dried methanol in the presence of varying amounts of room temperature ionic liquids (RTILs), 1-butyl-3-methylimidazolium acetate ([C4C1im][CH3COO]), 1-butyl-3-methylimidazolium chloride ([C4C1im]Cl) and 1-butyl-3-methylimidazolium hexafluorophosphate ([C4C1im][PF6]), were carried out in order to explore and understand the impact of these additives on the rate of such reactions. The observed results indicate that the rate constant of the reaction increase appreciably with increases in the concentration of RTILs in RTIL–methanol binary solvent systems. The results were analyzed in light of a Kamlet–Taft model system, which established that the observed impact of RTILs can be attributed to the cumulative effects of increase in the β value (hydrogen bonding acceptor ability) which is expected to enhance the reactivity of p-toluenesulfonyl chloride as well as the nucleophilicity of the azide ion and decrease in the π* value (solvent dipolarity/polarizability) which is expected to enhance the reactivity of the azide ion. Of the three ionic liquids used in the presented studies, [C4C1im][CH3COO] was observed to be more effective in accelerating the rate constant; this we attribute to its comparatively stronger ability to increase the β value and decrease the π* value in the mixed solvent system.


Ionic liquid (IL) Nucleophilicity Kinetics RTILs SN2 reaction Solvatochromism 



MAB thanks Department of Science and Technology, New Delhi, India, for the research grant No. SR/S1/PC-11/2009. MAR thanks CSIR for the financial assistance.


  1. 1.
    Welton, T.: Room temperature ionic liquids: solvents for synthesis and catalysis. Chem. Rev. 99, 2071–2084 (1999)CrossRefGoogle Scholar
  2. 2.
    Rogers, R.D., Seddon, K.R.: Ionic liquids: industrial applications to green chemistry. ACS Symposium Series 818. American Chemical Society, Washington, DC (2002)CrossRefGoogle Scholar
  3. 3.
    Poole, C.F.: Chromatographic and spectroscopic methods for the determination of solvent properties of room temperature ionic liquids. J. Chromatogr. A 1037, 49–82 (2004)CrossRefGoogle Scholar
  4. 4.
    Earle, M.J., Seddon, K.R.: Ionic liquids. Green solvents for the future. Pure Appl. Chem. 72, 1391–1398 (2000)CrossRefGoogle Scholar
  5. 5.
    Weingartner, H.: Understanding ionic liquids at the molecular level: facts, problems, and controversies. Angew. Chem. Int. Ed. 47, 654–670 (2008)CrossRefGoogle Scholar
  6. 6.
    Wasserscheid, P., Welton, T.: Ionic Liquids in Synthesis. Wiley, Weinheim (2003)Google Scholar
  7. 7.
    Lane, G.H., Bayley, P.M., Clare, B.R., Best, A.S., MacFarlane, D.R., Forsyth, M., Hollenkamp, A.F.: Ionic liquid electrolyte for lithium metal batteries: physical, electrochemical, and interfacial studies of N-methyl-N-butylmorpholinium bis(fluorosulfonyl)imide. J. Phys. Chem. C 114, 21775–21785 (2010)CrossRefGoogle Scholar
  8. 8.
    Forsyth, S.A., Pringle, J.M., MacFarlane, D.R.: Ionic liquids: an overview. Aust. J. Chem. 57, 113–119 (2004)CrossRefGoogle Scholar
  9. 9.
    Torriero, A.A.J., Siriwardana, A.I., Bond, A.M., Burgar, I.M., Dunlop, N.F., Deacon, G.B., MacFarlane, D.R.: Physical and electrochemical properties of thioether-functionalized ionic liquids. J. Phys. Chem. B 113, 11222–11231 (2009)CrossRefGoogle Scholar
  10. 10.
    Wasserscheid, P., Keim, W.: Ionic liquids–new “solutions” for transition metal catalysis. Angew. Chem. Int. Ed. 39, 3772–3789 (2000)CrossRefGoogle Scholar
  11. 11.
    Hallett, J.P., Welton, T.: Room temperature ionic liquids. solvents for synthesis and catalysis. 2. Chem. Rev. 111, 3508–3576 (2011)CrossRefGoogle Scholar
  12. 12.
    Hubbard, C.D., Illner, P., Eldik, R.V.: Understanding chemical reaction mechanisms in ionic liquids: successes and challenges. Chem. Soc. Rev. 40, 272–290 (2011)CrossRefGoogle Scholar
  13. 13.
    Hallet, J.P., Liotta, C.L., Ranieri, G., Welton, T.: Charge screening in the SN2 reaction of charged electrophiles and charged nucleophiles: an ionic liquid effect. J. Org. Chem. 74, 1864–1868 (2009)CrossRefGoogle Scholar
  14. 14.
    Kern, S., Illner, P., Begel, S., Van Eldik, R.: Mechanistic studies on fast ligand-substitution reactions of a very labile PdII complex in several ionic liquids. Eur. J. Inorg. Chem. 2010, 4658–4666 (2010)CrossRefGoogle Scholar
  15. 15.
    Behar, D., Gonzalez, C., Neta, P.: Reaction kinetics in ionic liquids: pulse radiolysis studies of 1-butyl-3-methylimidazolium salts. J. Phys. Chem. A 105, 7607–7614 (2001)CrossRefGoogle Scholar
  16. 16.
    Grodkowski, J., Neta, P.: Reaction kinetics in the ionic liquid methyltributylammonium bis(trifluoromethylsulfonyl)imide. Pulse radiolysis study of 4-mercaptobenzoic acid. J. Phys. Chem. A 106, 9030–9035 (2002)CrossRefGoogle Scholar
  17. 17.
    Skrzypczak, A., Neta, P.: Diffusion-controlled electron-transfer reactions in ionic liquids. J. Phys. Chem. A 107, 7800–7803 (2003)CrossRefGoogle Scholar
  18. 18.
    Sarkar, A., Trivedi, S., Pandey, S.: Unusual solvatochromism within 1-butyl-3-methylimidazolium hexafluorophosphate + poly (ethylene glycol) mixtures. J. Phys. Chem. B 112, 9042–9049 (2008)CrossRefGoogle Scholar
  19. 19.
    Sarkar, A., Trivedi, S., Pandey, S.: Polymer molecular weight-dependent unusual fluorescence probe behavior within 1-butyl-3-methylimidazolium hexafluorophosphate + poly(ethylene glycol). J. Phys. Chem. B 113, 7606–7614 (2009)CrossRefGoogle Scholar
  20. 20.
    Chaban, V.V., Prezhdo, O.V.: Ionic and molecular liquids: working together for robust engineering. J. Phys. Chem. Lett. 4, 1423–1431 (2013)CrossRefGoogle Scholar
  21. 21.
    Bogdanov, M.G., Svinyarov, I.: Ionic liquid-supported solid–liquid extraction of bioactive alkaloids. II. Kinetics, modeling and mechanism of glaucine extraction from Glaucium flavum Cr. (Papaveraceae). Sep. Purif. Technol. 103, 279–288 (2013)CrossRefGoogle Scholar
  22. 22.
    Tonovaa, K., Svinyarov, I., Bogdanov, M.G.: Hydrophobic 3-alkyl-1-methylimidazolium saccharinates as extractants for l-lactic acid recovery. Sep. Purif. Technol. 125, 239–246 (2013)CrossRefGoogle Scholar
  23. 23.
    Bhat, M.A., Dutta, C.K., Rather, G.M.: Exploring physicochemical aspects of N-alkylimidazolium based ionic liquids. J. Mol. Liq. 181, 142–151 (2013)CrossRefGoogle Scholar
  24. 24.
    Jan, R., Rather, G.M., Bhat, M.A.: Association of ionic liquids in solution: conductivity studies of [BMIM][Cl] and [BMIM][PF6] in binary mixtures of acetonitrile + methanol. J. Solution Chem. 42, 738–745 (2013)CrossRefGoogle Scholar
  25. 25.
    Jan, R., Rather, G.M., Bhat, M.A.: Effect of cosolvent on bulk and interfacial characteristics of imidazolium based room temperature ionic liquids. J. Solution Chem. 43, 685–695 (2014)CrossRefGoogle Scholar
  26. 26.
    Cowdrey, W.A., Hughes, E.D., Ingold, C.K., Masterman, S., Scott, A.D.: Reaction kinetics and the Walden inversion. Part VI. Relation of steric orientation to mechanism in substitutions involving halogen atoms and simple or substituted hydroxyl groups. J. Chem. Soc. 1937, 1252–1271 (1937)CrossRefGoogle Scholar
  27. 27.
    Lewis, G.N.: Valence and the Structure of Atoms and Molecules, vol. 113. Chemical Catalog Company, New York (1993)Google Scholar
  28. 28.
    Oslen, A.R.: The mechanism of substitution reactions. J. Chem. Phys. 1, 418–423 (1933)CrossRefGoogle Scholar
  29. 29.
    Chiappe, C., Pieraccini, D.: Ionic liquids: solvent properties and organic reactivity. J. Phys. Org. Chem. 18, 275–297 (2005)CrossRefGoogle Scholar
  30. 30.
    Perrin, D.D., Armarego, W.L.F.: Purification of Laboratory Chemical, 3rd edn. Pregamon Press, Great Britian (1998)Google Scholar
  31. 31.
    Dupont, J., Consorti, C.S., Saurez, P.A.Z., deSouza, R.F.: Preparation of 1-butyl-3-methyl imidazolium–based room temperature ionic liquids. Org. Synth. 79, 236–243 (2002)CrossRefGoogle Scholar
  32. 32.
    Dupont, J., Consorti, C.S., Saurez, P.A.Z., deSouza, R.F.: Preparation of 1-butyl-3-methyl imidazolium-based room temperature ionic liquids. Org. Synth. 10, 184–188 (2004)Google Scholar
  33. 33.
    Bhat, M.A., Chaudhari, V.R., Ingole, P.P., Harram, S.K.: Outer sphere electroreduction of CCl4 in 1-butyl-3-methylimmidazolium tetrafluoroborate: an example of solvent specific effect of ionic liquid. J. Phys. Chem. B 113, 2848–2853 (2009)CrossRefGoogle Scholar
  34. 34.
    Ryu, Z.H., Lee, S.W., D’Souza, M.J., Yaakoubd, L., Feld, S.E., Kevill, D.N.: Correlation of the rates of solvolysis of two arenesulfonyl chlorides and of trans-β-styrenesulfonyl chloride: precursors in the development of new pharmaceuticals. Int. J. Mol. Sci. 9, 2639–2657 (2008)CrossRefGoogle Scholar
  35. 35.
    Rogne, O.: Kinetics of the pyridine-catalysed methanolysis of aromatic sulphonyl chlorides. J. Chem. Soc. B 1971, 1334–1337 (1971)CrossRefGoogle Scholar
  36. 36.
    Jessop, P.G., Jessop, D.A., Fu, D., Phan, L.: Solvatochromic parameters for solvents of interest in green chemistry. Green Chem. 14, 1245–1259 (2012)CrossRefGoogle Scholar
  37. 37.
    Li, Y.X., Bao, W.L., Wang, Z.M.: Substitution reaction by azide and thiocyanide anions in room temperature ionic liquids. Chin. Chem. Lett. 14, 239–242 (2003)Google Scholar
  38. 38.
    Oh, H.K., Park, C.Y., Lee, J.M., Lee, I.: Nucleophilic substitution reactions of thiophenyl dimethylacetates and trimethylacetates with benzylamines in acetonitrile. Bull. Korean Chem. Soc. 22, 383–387 (2001)Google Scholar
  39. 39.
    Jorapur, Y.R., Chi, D.Y.: Ionic liquids: as environmentally friendly media for nucleophilic substitution reactions. Bull. Korean Chem. Soc. 27, 345–354 (2006)CrossRefGoogle Scholar
  40. 40.
    Lancaster, N.L., Welton, T., Young, G.B.: A study of halide nucleophilicity in ionic liquids. J. Chem. Soc. Perkin Trans. 2, 2267–2270 (2001)CrossRefGoogle Scholar
  41. 41.
    Lancaster, N.L., Salter, P.A., Welton, T., Young, G.B.: Nucleophilicity in ionic liquids. 2.1 Cation effects on halide nucleophilicity in a series of bis(trifluoromethylsulfonyl) imide ionic liquids. J. Org. Chem. 67, 8855–8861 (2002)CrossRefGoogle Scholar
  42. 42.
    Raniere, G., Hallet, J.P., Welton, T.: Nucleophilic reactions at cationic centers in ionic liquids and molecular solvents. Ind. Eng. Chem. Res. 47, 638–644 (2008)CrossRefGoogle Scholar
  43. 43.
    D’Anna, F., Frenna, V., Noto, R., Pace, V., Spinelli, D.: Study of aromatic nucleophilic substitution with amines on nitrothiophenes in room-temperature ionic liquids: are the different effects on the behavior of para-like and ortho-like isomers on going from conventional solvents to room-temperature ionic liquids related to solvation effects? J. Org. Chem. 71, 5144–5150 (2006)CrossRefGoogle Scholar
  44. 44.
    D’Anna, F., Marullo, S., Noto, R.: Aryl azides formation under mild conditions: a kinetic study in some ionic liquid solutions. J. Org. Chem. 75, 767–771 (2010)CrossRefGoogle Scholar
  45. 45.
    Crowhurst, L., Falcone, R., Lancaster, N.L., LIopis-Mestre, V., Welton, T.: Using Kamlet–Taft solvent descriptors to explain the reactivity of anionic nucleophiles in ionic liquids. J. Org. Chem. 71, 8847–8853 (2006)CrossRefGoogle Scholar
  46. 46.
    Reichardt, C.: Solvents and Solvent Effects in Organic Chemistry, 3rd edn. Wiley, Weinheim (2003)Google Scholar
  47. 47.
    Ingold, C.K.: Structure and Mechanism in Organic Chemistry, 2nd edn. Bell, London (1969)Google Scholar
  48. 48.
    Kamlet, M.J., Abboud, J.L., Taft, R.W.: The solvatochromic comparison method. 6. The π* scale of solvent polarities. J. Am. Chem. Soc. 99, 6027–6038 (1977)CrossRefGoogle Scholar
  49. 49.
    Kamlet, M.J., Taft, R.W.: The solvatochromic comparison method. I. The β-scale of solvent hydrogen-bond acceptor (HBA) basicities. J. Am. Chem. Soc. 98, 377–383 (1976)CrossRefGoogle Scholar
  50. 50.
    Taft, R.W., Kamlet, M.J.: The solvatochromic comparison method. 2. The alpha scale of solvent hydrogen–bond donor (HBD) acidities. J. Am. Chem. Soc. 98, 2886–2894 (1976)CrossRefGoogle Scholar
  51. 51.
    Yokoyama, T., Taft, R.W., Kamlet, M.J.: The solvatochromic comparison method. 3. Hydrogen bonding by some 2-nitroaniline derivatives. J. Am. Chem. Soc. 98, 3233–3237 (1976)CrossRefGoogle Scholar
  52. 52.
    Kamlet, M.J., Abraham, M.H., Taft, R.W.: Linear solvation energy relationships. 23. A comprehensive collection of the solvatochromic equation. J. Org. Chem. 48, 2877–2887 (1983)CrossRefGoogle Scholar
  53. 53.
    Crowhurst, L., Lancaster, N.L., Arlandis, J.M.P., Welton, T.: Manipulating solute nucleophilicity with room temperature ionic liquids. J. Am. Chem. Soc. 126, 11549–11555 (2004)CrossRefGoogle Scholar
  54. 54.
    Gonçalves, R.M.C., Simões, A.M.N., Albuquerque, L.M.P.C., Rosés, M., Ràfols, C., Bosch, E.: Kamlet–Taft solvatochromic parameters for hydroxylic solvents. J. Chem. Res., Synop. 6, 214–215 (1993)Google Scholar
  55. 55.
    Nicolet, P., Laurence, C.: Polarity and basicity of solvents. Part 1. A thermosolvatochromic comparison method. J. Chem. Soc. Perkin Trans. 2, 1071–1079 (1986)CrossRefGoogle Scholar
  56. 56.
    Reichardt, C.: Solvatochromic dyes as solvent polarity indicators. Chem. Rev. 94, 2319–2358 (1994)CrossRefGoogle Scholar
  57. 57.
    Jelicˇic´, A., Garcia, N., Löhmannsröben, H.G., Beuermann, S.: Prediction of the ionic liquid influence on propagation rate coefficients in methyl methacrylate radical polymerizations based on Kamlet–Taft solvatochromic parameters. Macromolecules 42, 8801–8808 (2009)CrossRefGoogle Scholar
  58. 58.
    Doherty, T.V., Mora-Pale, M., Foley, S.E., Linhardt, R.J., Dordick, J.S.: Ionic liquid solvent properties as predictors of lignocellulose pretreatment efficacy. Green Chem. 12, 1967–1975 (2010)CrossRefGoogle Scholar
  59. 59.
    Mancini, P.M., Fortunato, G.G., Vottero, L.R.: Molecular solvent/ionic liquid binary mixtures: designing solvents based on the determination of their microscopic properties. Phys. Chem. Liq. 42, 625–632 (2004)CrossRefGoogle Scholar
  60. 60.
    Trivedi, S., Malek, N.I., Behera, K., Pandey, S.: Temperature-dependent solvatochromic probe behavior within ionic liquids and (ionic liquid + water) mixtures. J. Phys. Chem. B. 114, 8118–81125 (2010)CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 2015

Authors and Affiliations

  • Mudasir Ahmad Rather
    • 1
  • Ghulam Mohammad Rather
    • 1
  • Sarwar Ahmad Pandit
    • 1
  • Sajad Ahmad Bhat
    • 1
  • Khaliquz Zaman Khan
    • 1
  • Mohsin Ahmad Bhat
    • 1
  1. 1.Department of ChemistryUniversity of KashmirSrinagarIndia

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