Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5411772 | Journal of Molecular Liquids | 2013 | 7 Pages |
Abstract
Densities, viscosities and refractive index, as a function of temperature, and isobaric thermal expansion coefficient, were determined for 1-alkyl-3-methylimidazolium hexafluorophosphate, [CN â 1C1im][PF6] (where N = 5 to 10) series of ionic liquids. The density presents a regular decrease along the ionic liquid series, with no detectable alkyl chain length dependence of the thermal expansion coefficient. Both the refractive index and viscosity show a trend shift along the series around the [C6C1im][PF6] that could be associated to the impact of the change in the nanostructuration of the ionic liquids. The experimental results are compared with the analogous [CN â 1C1im][NTf2] series and the effect of the anion is analyzed. The sphericity of the [PF6]â anion is reflected in the lower pre-exponential VTF parameter, Aη, and the higher viscosity of the [CN â 1C1im][PF6], when compared with the [CN â 1C1im][NTf2] series, is ruled by the higher energy barriers, which are related with stronger electrostatic interaction due to the low charge dispersion of the [PF6]â.anion.
Keywords
Related Topics
Physical Sciences and Engineering
Chemistry
Physical and Theoretical Chemistry
Authors
Marisa A.A. Rocha, Filipe M.S. Ribeiro, Ana I.M.C. Lobo Ferreira, João A.P. Coutinho, LuÃs M.N.B.F. Santos,