Pulse radiolysis studies of intermediates derived from p‐terphenyl in the oxygenated methyltributylammonium bis[(trifluoromethyl)sulfonyl]imide ionic liquid

Abstract

AbstractRadiation‐induced processes in oxygenated ionic liquid (IL) methyltributylammonium bis[(trifluoromethyl)sulfonyl]imide ([MeBu3N][NTf2]) solutions containing p‐terphenyl (TP) were investigated by the nanosecond pulse radiolysis with UV‐vis detection. The transient absorption spectra generated in these solutions were assigned to radical anions (TP•−), radical cations (TP•+), and triplet excited states (3TP*). Saturation of [MeBu3N][NTf2] solutions with oxygen (O2) efficiently eliminates solvated electrons (esolv−); however, it does not decrease significantly the radiation chemical yield of TP•−, which are mainly formed in a reaction of TP with presolvated electrons (epresolv−). On the other hand, the lifetime of TP•− decreases significantly due to their reaction with O2. The TP•+ is formed in a reaction of electron‐deficient centers of the IL (IL⊕) with TP. Their radiation chemical yield and lifetime are not affected by the presence of O2; however, they are decreased by the presence of triethylamine (TEA). The 3TP* are formed in a reaction of excited states of ionic liquid (IL*) with TP. The presence of O2 and TEA effectively eliminates 3TP* in the time domain >1 μs.