A SUBSTITUTED IMIDAZOLIUM CHLOROALUMINATE MOLTEN-SALT POSSESSING AN INCREASED ELECTROCHEMICAL WINDOW

The preparation and characterization of a new molten salt system prepared from aluminum chloride and a trialkylimidazolium halide is described, particularly those molten salts prepared with l,2-dimethyl-3-propylimidazolium chloride. Molten salts prepared with this salt are liquid over the composition range of ca. 0.65:1 to 2.2:1 AlCl3:DMPrICl at 25°C. A value for the acid-base equilibrium constant of (2.0 ± 0.5) x 10-15was determined by potentiometric titration. Cyclic voltammetry results are presented comparing reduction potentials for MEIC1 and DMPrICl and the electrochemical windows of the respective molten salts. For a 1:1 AlCl3:DMPrICl molten salt, an electrochemical window of nearly 5V is obtained at glassy carbon. © 1987, The Electrochemical Society, Inc. All rights reserved.