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

Abstract

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 (O2−) in ILs is one of these interesting areas. In this work O2− was generated and analyzed electrochemically using cyclic voltammetry and chronoamperometry techniques from O2 dissolved in 1-butyl-1-methylpyrrolidinium trifluoroacetate, [BMPyrr][TFA]. Moreover, O2− was generated chemically by the addition of potassium superoxide (KO2) into the same IL. UV/Vis spectrophotometer was used for testing the stability of the generated O2− and GC/MS was used to investigate any possible reaction between [BMPyrr][TFA] and O2−. For our best knowledge this is the first time that trifluoroacetate based IL was used for the generation of O2−. The results showed that O2− was very stable in this IL. This encourages further investigation on the use of this particular class of ILs in diverse applications involving the O2−. The chemically generated O2− by dissolving KO2 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 KO2 for destruction of chloroethanes in ILs.