The use of controlled potential electrolysis with a dropping mercury electrode in elucidation of organic electroreduction mechanisms

Controlled potential electrolysis with the dropping mercury electrode, in which a small volume (typically 0.5 to 1.0 mL) of the electrolyzed solution is stirred by the falling off drops, enables coulometric and mechanistic studies unaffected by products formed at the electrode surface. Such electrodes allow establishment of equipotential conditions over the whole electrode surface. Electrolysis is practically complete within 8 to 12 h. When electrolysis products or stable intermediates are electroactive, recording of current-voltage curves during the electrolysis allows detection and following of relatively slow chemical reactions (with hall-lives of the order of tens of minutes) which might affect results of preparative electrolyses and would otherwise remained undetected. Reactions of electrogenerated species with limited lifetimes can be followed in this way which would be difficult to detect and follow by other techniques.