A kinetic and mechanistic study of the electrochemical oxidation of hydroquinone in 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, [C2mim][NTf2]

The kinetics and mechanism of the oxidation of hydroquinone is studied in the room temperature ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, [C2mim][NTf2]. The two-electron transfer oxidation is shown to lead to the rapid release of two protons and the formation of benzoquinone which can be reduced itself at sufficient negative potentials. Tafel analysis and simulation show that the second electron transfer is rate determining. The protons lost are shown to associate with the anion of the RTIL leading to the reduction of bistrifluoromethanesulfonimide, HNTf2 acid. This species can also undergo reduction on the reverse cathodic going voltage sweep.