Aluminium 1-ethyl-3-methylimidazolium

In the report by Carter et al. [9], the electrogenerated superoxide species was found to be unstable in the IL l-ethyl-3-methylimidazolium chloride mixed with aluminium chloride. The irreversibility was attributed to the introduction of a proton source when the molten salt was saturated with O2. Removal of the protons from the melt under vacuum was unsuccessful. Scheme 18.3 was proposed in that work to explain the detrimental effect of strong protic additives on the stability of the superoxide anion. 

Therefore, a possible mechanism for quaternary phosphonium ILs was proposed, involving several electrochemical and chemical steps, in a similar manner to that described by Carter [9] for the ORR in 1-ethyl-3-methylimidazolium chloride mixed with aluminium chloride in the presence of hydrochloric acid. The first starting step involves the reduction of oxygen to yield superoxide as described in Eq. 18.7, followed by a-proton abstraction (Eq. 18.18) and subsequent disproportionation reaction of HO2 (Eq. 18.10). 

Jiang, T., Chollier Brym, M.J., Dube, G. et al. (2006) Electrodeposition of aluminium from ionic liquids part I - electrodeposition and surface morphology of aluminium from aluminium chloride (AlCljl-l-ethyl-S-methylimidazolium chloride ([EMImJCl) ionic liquids. Surf. Coat. Technol, 201(1/2), 1-9. 

Thus a large number of ambient temperature ionic liquids can be formed from a mixture of solid aluminium(ni) chloride and solid 1-ethyl-3-methylimidazolium chloride. Mixing these two salts together results in an exothermic reaction and generation of a clear, colorless liquid, and an ambient temperature molten salt with low viscosity. We can see... 

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