Vanadium oxide complexes in room-temperature chloroaluminate molten salts

The dissolution of vanadium(V) oxide (V2O5) in various ionic liquids has be en studied to determine the complexes formed with respect to melt compositi on and V2O5 concentration. Vanadium oxide did not dissolve in either 1-n-bu tyl-3-methylimidazolium tetrafluoroborate or 1-n-butyl-3-methylimidazolium trifluoromethanesulfonate ionic liquids. V2O5 was found to dissolve at temp eratures greater than 70 degrees C in 1-ethyl- and 1-n-butyl-3-methylimidaz olium tetrachloroaluminate ionic liquids. Analyses of vanadium-containing m elts by V-51, H-1, and C-13 NMR and infrared spectroscopy indicate the emer gence of different species as a function of melt acidity. In basic and neut ral melts, VO2Cl2- and a metavanadate species of the form [(VO3)(n)](n-) ar e observed. The species VO2Cl2- is the prominent product in basic melts, bu t as the melt becomes neutral or as the concentration of V2O5 is increased, the concentration of the metavanadate species is found to increase. Howeve r, V2O5 has been found to react in acidic melts to form volatile VOCl3.