Electrochemistry of Vanadium Oxides and Oxyhalides in Chloroaluminate Room Temperature Ionic Liquids: Formation of a New Ionic Liquid

The electrochemistry of several vanadium oxides and oxyhalides has been examined in room temperature ionic liquids made by mixing 1-ethyl-3-methylimidazolium chloride (EMIC) and aluminum chloride. By varying the mole ratio of the two components, Lewis basic, neutral, and acidic ionic liquids were formed, while the addition of NaCl to an acidic ionic liquid resulted in a Lewis buffered, neutral solvent. Because of the ionic nature of these liquids, most oxides have very low solubility: and are insoluble, while and are slightly soluble with solubility limits of less than 5 mM. The solubilities of the salts and and the oxyhalides and are significantly higher. In acidic ionic liquids, and all exhibit three irreversible reduction waves between 1.7 and 0.5 V vs. a reference electrode consisting of an aluminum wire in a 0.6 mole fraction ionic liquid. and gave similar reduction peaks, suggesting that the oxides may have reacted with the ionic liquid to form oxychlorides. A new ionic liquid was formed by using as the Lewis acid instead of In acetonitrile underwent a one-electron reversible reduction to © 2002 The Electrochemical Society. All rights reserved.