Generation of superoxide ion in 1-butyl-1-methylpyrrolidinium trifluoroacetate and its application in the destruction of chloroethanes

Ionic liquids (ILs) have attracted the curiosity of researchers due to their unique properties in different applications such as separation, extraction, purification, catalysis and electrochemical applications. The generation of superoxide ion (O ₂ ^-) in ILs is one of these interesting areas. In this work O ₂ ^- was generated and analyzed electrochemically using cyclic voltammetry and chronoamperometry techniques from O ₂ dissolved in 1-butyl-1-methylpyrrolidinium trifluoroacetate, [BMPyrr][TFA]. Moreover, O ₂ ^- was generated chemically by the addition of potassium superoxide (KO ₂) into the same IL. UV/Vis spectrophotometer was used for testing the stability of the generated O ₂ ^- and GC/MS was used to investigate any possible reaction between [BMPyrr][TFA] and O ₂ ^-. For our best knowledge this is the first time that trifluoroacetate based IL was used for the generation of O ₂ ^-. The results showed that O ₂ ^- was very stable in this IL. This encourages further investigation on the use of this particular class of ILs in diverse applications involving the O ₂ ^-. The chemically generated O ₂ ^- by dissolving KO ₂ was then used for the destruction of hexachloroethane in [BMPyrr][TFA] under ambient conditions. The destruction percentage was higher than 98%. This work presents the first attempt to utilize KO ₂ for destruction of chloroethanes in ILs.