ON THE MECHANISM OF THE CATHODIC REDUCTION OF ANTHRAQUINONE TO ANTHRONE.

Article abstract of DOI:10.1002/bbpc.19870910109

The cathodic reduction of anthraquinone in 85% H//2SO//4 at cathodes of glassy carbon or mercury has been investigated. Voltammetric curves exhibit two steps at plus 0. 23 and plus 0. 10 V vs. SHE. The limiting current densities show a ratio between 4:0 via 1:1 to 1:3, depending on the experimental conditions. Experiments at the RRDE indicate two reoxidizable intermediates. We derive a mechanism from our findings, involving the electrochemical formation of these intermediates, anthrasemiquinone AQH multiplied by (times) and anthrahydroquinone AQH//2. Both are subject to a bimolecular follow up reaction (disproportionation) to yield AQH//2 and anthrone. The rate constants are estimated to be 2. 10**3 and 3. 10**4 1 mol** minus **1 s** minus **1, respectively. Anthrone is the only reduction product which could be isolated.