Application of 12CaO•7Al2O3 electride as a new electrode for superoxide ion generation and hydroxylation of an arylboronic acid

12CaO•7Al2O3 (C12A7) electride, which exhibits metallic conduction and 2.4 eV work function, can be used as an electron emitter and chemical reagent. Herein we reveal a new application for C12A7 electride as electrode in electrochemical reactions. Cathodic reduction of oxygen at C12A7 electrode in acetonitrile generates superoxide ions (O2•−) using Bu4NClO4 as a supporting electrolyte. Iodometry reveals that this electrode shows a higher yield of O2•− ions than conventional electrodes such as Pt and glassy carbon. Moreover, O2•– ion–induced hydroxylation of p-(methylthio)phenylboronic acid using C12A7 electrode gives the corresponding phenol derivative with a yield of 90% at the charge apply of 2.5 F·mol− 1.

► In this study, the electrogeneration of O2•− ion was firstly observed at C12A7 electride electrode. ► C12A7 electrode gave higher yield on the O2•− ion formation than GC and Pt electrodes. ► C12A7 electrode showed higher efficiency on the O2•− ion–induced hydroxylation of p-(methylthio)phenylboronic acid than GC and Pt electrodes, a corresponding phenol with a yield over 90% was achieved at a charge apply of 2.5 F·mol− 1.