Abstract

Hexamethylbenzene reacts differently with zirconiumand hafnium tetrachloride, affording, for the former, abinuclear molecular complex Zr(η⁶-Me₆C₆)Cl₂(μ-Cl)₃ZrCl₃ and for the latter a binuclear ionic complex [Hf(η⁶-Me₆C₆)Cl₃]+[Hf₂Cl₉]-. This difference in reactivity is exploited to carryout a two-phase extraction using 1-butyl-3-methylimidazoliumtetrachloroaluminate as the ionic liquid phase and a toluene/pentane mixture as the organic phase. This technique presentsthe potential advantage of recovering pure zirconium chloridewithout the formation of highly inert oxides.