In the last decade, protic ionic liquids have been attracted remarkable attention as fuel cell electrolytes. According to Angell, an ionic liquid whose Walden plot locates avobe the ideal Walden line should be classified into superionic one. In this context, ?pKamay be a good measure for the ioni-ion interaction in protic ionic liquids.Recently, we found equimolar mixture of N-methylimidazole and acetic acid is not a ionic liquid in terms of pKs (auto-protolysis constant experimentally evaluated in the liquid).1 However, this mixture has significant electric conductivity. Raman spectroscopic data suggests no ionic species practically exists in this mixture. If taking it into consideration, the Walden plots for this mixture locates above the ideal Walden line; i.e., this mixture should be classified into superionic. Hense, we proposed this new kind of liquids as pseudo-protic ionic liquids.2 Pseudo-protic ionic liquids have significant ionic conductivity without acid dissociation. Here, we point out possibility of super Arrhenius ion conduction.In this contribution, we introduce new pseudo-ionic liquids; their macroscopic transport properties such as ionic conductivity and viscosity. We also show their liquid structure and collective dynamics based on the high-energy X-ray diffraction, dielectric relaxation and low-frequency Raman experiments. Finally, we discuss possible proton conductive mechamnism. References  1. R. Kanzaki, H. Doi, X. Song, S. Hara, S. Ishiguro, Y. Umebayashi, J. Phys. Chem. B 2012  , 116, 14146.2. H. Doi, X. Song, B. Minofar, R. Kanzaki, T. Takamuku, Y. Umebayashi, Chem. Eur. J. 2013  , 19, 11522.

Possibility of super Arrhenius ion conduction: Pseudo-protic ionic liquids

248th National Meeting (2014)

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