Anthraquinone Electroreduction Mechanism in 0.1 M Tetrabutylammonium Bromide in Dimethyl Sulfoxide

Electroreduction of anthraquinone in 0.1 M tetrabutylammonium bromide in dimethyl sulfoxide is studied by cyclic voltammetry in an argon atmosphere at 373–423 K. According to steady- and non-steady-state measurements, the process involves two one-electron stages at potentials of –0.6 to –0.7 and –1.5 to –1.6 V vs. a quasi-reversible platinum electrode. The electrode material (platinum, silver, glassy carbon) barely affects the electroreduction mechanism. The process is controlled by the mass transfer rate. Anthraquinone can be reduced to mono- and diphenoxide anions. Optimum conditions for obtaining the latter are found.