14589-06-1Relevant articles and documents
The ferro/ferricyanide couple in an aluminum chloride-1-methyl-3-ethylimidazolium chloride ambient-temperature molten salt
Das,Carlin,Osteryoung
, p. 421 - 426 (2008/10/08)
Tetrabutylammonium ferricyanide, (Bu4N)3Fe(CN)6, has been prepared and investigated in the 1-methyl-3-ethylimidazolium chloride-aluminum chloride (ImCl-AlCl3) ambient-temperature molten salt solvent. The voltammetry and UV-visible spectroscopy of (Bu4N)3Fe(CN)6 have been compared to those of K3Fe(CN)6 in water and are shown to be identical; in addition, the molecular weight of (Bu4N)3Fe(CN)6 has been determined by an electroanalytical method and is in good agreement with that expected. (Bu4N)3Fe(CN)6 is insoluble in the basic ImCl-AlCl3 melt but is soluble in the acidic melt. However, the ferricyanide reacts to form the ferrocyanide species; i.e., the oxidation potential of the ferro/ferricyanide couple is sufficiently positive to oxidize chloride from tetrachloroaluminate. Spectral shifts observed for the molten salt suggest that AlCl3 forms adducts with the ferrocyanide, which accounts for the large positive shift in the oxidation potential of the ferro/ferricyanide redox couple relative to that in water. The ferro/ferricyanide couple could be examined voltammetrically at a carbon, but not at a platinum, electrode since the tetrachloroaluminate oxidation is significantly more irreversible on the former than the latter, and the formal potential was estimated as +2.30 V vs an Al reference in the 1.5:1 molten salt.
