Effect of ionic size on solvate stability of glyme-based solvate ionic liquids
Artikel i vetenskaplig tidskrift, 2015

A series of binary mixtures composed of glymes (triglyme, G3; tetraglyme, G4; pentaglyme, G5) and alkali-metal bis(trifluoromethanesulfonyl)amide salts (M[TFSA]; M = Li, Na, and K) were prepared, and the correlation between the composition and solvate stability was systematically investigated. Their phase diagrams and Raman spectra suggested complexation of the glymes with M[TFSA] in 1:1 and/or 2:1 molar ratio(s). From isothermal stability measurements, it was found that the formation of structurally stable complexes in the solid state did not necessarily ensure their thermal stability in the liquid state, especially in the case of 2:1 complexes, where uncoordinating or highly exchangeable glyme ligands existed in the molten complexes. The phase-state-dependent Raman spectra also supported the presence of free glymes in certain liquid complexes. The effect of the electric field induced by the alkali-metal cations on the oxidative stability of certain glyme complexes was examined by linear sweep voltammetry and quantum chemical calculations. Although the actual oxidative stability of complexes did not necessarily reflect the calculated HOMO energy levels of the glymes, the strong electric field induced by the smaller M+ cations and proper coordination structures impart high stability to the glyme complexes. The results of thermogravimetry of complexes with different M+ cations revealed that a balance of competitive interactions of the M+ ions with the glymes and [TFSA]- anions predominates the thermal stability. (Chemical Equation Presented).


Toshihiko Mandai

Chalmers, Teknisk fysik, Kondenserade materiens fysik

Kazuki Yoshida

Yokohama National University

Seiji Tsuzuki

National Institute of Advanced Industrial Science and Technology (AIST)

Risa Nozawa

Yokohama National University

Hyuma Masu

Chiba University

Kazuhide Ueno

Yokohama National University

Kaoru Dokko

Kyoto University

Yokohama National University

Masayoshi Watanabe

Yokohama National University

Journal of Physical Chemistry B

1520-6106 (ISSN) 1520-5207 (eISSN)

Vol. 119 4 1523-1534


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