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Physical and electrochemical properties of thioether-functionalized ionic liquids

journal contribution
posted on 2009-07-23, 00:00 authored by Angel TorrieroAngel Torriero, A Siriwardana, A Bond, I Burgar, N Dunlop, G Deacon, D MacFarlane
The preparation and characterization of a series of ionic liquids based on S-alkyl thiolonium, S-alkyl thiotetrazolium, or S-alkyl thiobenzolium cations coupled with bis(trifluoromethanesulfonyl)amide, trifluoromethanesulfonate, alkyl phosphate, chloride, and hexafluorophosphate anions are reported. All are liquid at room temperature, except the chloride salt, which has a melting point of 92 °C. The electrochemical characteristics of this class of ionic liquid have been determined by cyclic voltammetry. Potential windows of the ionic liquids have been obtained at glassy carbon, platinum, and gold electrodes and found to be the largest at glassy carbon, but are limited by oxidation of the thioether-functionalized cation. The voltammetry of IUPAC reference potential scale systems, ferrocene/ferrocenium, cobaltocenium/cobaltocene, and decamethylferrocene/decamethylferrocenium have been evaluated, with the last being most widely applicable. Nonadditivity of Faradaic current is found in the voltammograms of decamethylferrocene in the presence of ferrocene and cobaltocenium. Diffusion coefficient, viscosity, ionic conductivity, double layer capacitance, and other physical properties have also been measured. The dependence of the diffusion coefficient vs viscosity follows the Stokes−Einstein relationship. The properties of the ionic liquids are compared with the related imidazolium family of ionic liquids.

History

Journal

The journal of physical chemistry b

Volume

113

Issue

32

Pagination

11222 - 11231

Publisher

American Chemical Society

Location

Washington D.C.

ISSN

1520-6106

eISSN

1520-5207

Language

eng

Publication classification

C1.1 Refereed article in a scholarly journal

Copyright notice

2009, American Chemical Society