Volatility of some [CnCnim][NTf2] ionic liquids


M. Rocha1, B. Schroder2, J. Coutinho2 and L. Santos1

1Centro de Investigacao em Quimica, Faculdade de Ciencias da Universidade do Porto, Porto, Portugal
2CICECO, Departamento de Quimica, Universidade de Aveiro, Aveiro, Portugal

Keywords: vapour pressures, volatility, Knudsen effusion
property: vapour pressures, standard molar enthalpies, entropies and Gibbs energies of vaporization
material: ionic liquids

Room temperature ionic liquids, RTILs, have been intensively studied due to their unusual and interesting properties. One of the most peculiar properties of these systems is their extremely low vapour pressure at room temperature, which makes them distinct from molecular liquids. The knowledge of vapour pressures of ILs is fundamental for the development of theoretical models and for the interpretation of many other physical properties. The present work is part of a wider project, dealing with the thermodynamic study of pure ionic liquids, focused on a highly accurate volatility study of ionic liquids. The vapour pressures of 1,3-dialkylimidazolium bis(trifluoromethylsulfonyl)imide ([CnCnim][NTf2] where n = 1 - 6) were measured using a Knudsen effusion apparatus combined with a quartz crystal microbalance, described recently in the literature.[1] Based on the previous data, the standard molar enthalpies, entropies and Gibbs energies of vaporization were derived. The results obtained will be used to evaluate the effect of the cation topological symmetry and to dissect the enthalpic and entropic contribution to the ILs volatility. Acknowledgements: Fundação para a Ciência e Tecnologia (FCT) and Programa Operacional Ciência e Inovação 2010 (POCI 2010) supported by the European Community Fund FEDER is acknowledge for the financial support to Project PTDC/QUI/72903/2006. B. Schröder and M. A. A. Rocha acknowledge the financial support from F.C.T. for the award of a research grant with reference SFRH/BPD/38637/2007 and SFRH/BD/60513/2009, respectively.

References
  1. L.M.N.B.F. Santos, L.M.S.S. Lima, C.F.R.A.C. Lima, F.D. Magalhães, M.C. Torres, B. Schroder, M.A.V. Ribeiro da Silva, J. Chem. Thermodyn. (2011) doi:10.1016/j.jct.2010.12.022

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