Reaction of Chloride Ions in Low-Temperature Molten Salts and Application to the Study of Complex Ion Stoichiometry

摘要

The oxidation of chloride ions added as a slight excess to a neutral ambient-temperature ionic liquid of either N-n-bu-tylpyrdinium chloride or 1-methyl-3-ethylimidazolium chloride mixed with an equivalent amount of aluminum chloride has been found to yield an oxidation wave indicating convective diffusion control at a rotating platinum electrode. The oxidation wave is linear in the square root of the rotation rate of the electrode and directly proportional to the amount of chloride in the molten salt up to ca. 0.1 mol/cu dm. Coulometry carried out under conditions similar to those prevailing at the rotating disk electrode indicates the oxidation of cl(-) is to cl3(-). This chloride oxidation wave in the neutral melt can be applied to study the stoichiometry of chloro-complex species formed, even if the chloro complex is itself not electroactive. Application to the determination of the number of chlorides bound to Fe(III) is presented. (Author).