Solubility and Stability of Superoxide Radical Anions in Room-Temperature Ionic Liquids

Because superoxide anion is easily decomposed by the presence of proton, it is known that superoxide anion only dissolves in specific highly polar aprotic solvents such as dimethylsulfoxide. Organic solvents are dangerous due to their high volatility and flammability, while ionic liquids possess inflammability, nonvolatility, and high ion conductivity. Additionally, in the area of organic synthesis, there is a potential for a new reaction media different from existing organic reaction media. Therefore, it would be attractive to use ILs as a new reaction media and an electrolyte of batteries. In this study, we studied solubility and stability of superoxide anion in five kinds of ILs. It was found that P14,6,6,6Cl was the most suitable solvent in terms of the solubility and stability of superoxide anion.