Ether-Bond-Containing Ionic Liquids and the Relevance of the Ether Bond Position to Transport Properties

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• 作者：Marcelo J. Monteiro ; Fernanda F. Camilo ; Mauro C. C. Ribeiro ; Roberto M. Torresi
• 刊名：Journal of Physical Chemistry B
• 出版年：2010
• 出版时间：October 7, 2010
• 年：2010
• 卷：114
• 期：39
• 页码：12488-12494
• 全文大小：295K
• 年卷期：v.114,no.39(October 7, 2010)
• ISSN：1520-5207

文摘

The ionic liquids (ILs) 1-ethoxyethyl-2,3-dimethylimidazolium bis(trifluoromethanesulfonyl)imide, [EtO(CH₂)₂MMI][Tf₂N], and N-(ethoxyethyl)-N-methylmorpholinium bis(trifluoromethanesulfonyl)imide, [EtO(CH₂)₂MMor][Tf₂N] were synthesized, and relevant properties, such as thermal stability, density, viscosity, electrochemical behavior, ionic conductivity, and self-diffusion coefficients for both ionic species, were measured and compared with those of their alkyl counterparts, 1-n-butyl-2,3-dimethylimidazolium bis(trifluoromethanesulfonyl)imide, [BMMI][Tf₂N], and N-n-butyl-N-methylpiperidinium bis(trifluoromethanesulfonyl)imide, [BMP][Tf₂N] and N-n-butyl-N-methylmorpholinium bis(trifluoromethanesulfonyl)imide [BMMor][Tf₂N]. This comparison was done to evaluate the effects caused by the presence of the ether bond in either the side chain or in the organic cation ring. The salt, LiTf₂N, was added to the systems to estimate IL behavior with regard to lithium cation transport. Pure [EtO(CH₂)₂MMI][Tf₂N] and their LiTf₂N solutions showed low viscosity and the highest conductivity among the ILs studied. The H_R (AC conductivity/NMR calculated conductivity ratio) values showed that, after addition of LiTf₂N, ILs containing the ether bond seemed to have a greater number of charged species. Structural reasons could explain these high observed H_R values for [EtO(CH₂)₂MMor][Tf₂N].