Application of ultrasound technology to electroorganic synthesis: Reduction of acetophenone

Electroreduction of acetophenone in an undivided cell was chosen as a model reaction to investigate the use of ultrasonication in organic electrosynth esis. The reaction was carried out in aqueous medium (water-methanol), at n eutral pH and at a cadmium or zinc cathode. Electrochemical reduction of ac etophenone yields alcohol through a bielectronic transfer and pinacol throu gh a monoelectronic transfer. Operating conditions permit to modify the red uction state of the reactant. On a cadmium cathode, the major product is th e alcohol whereas on a zinc cathode, the pinacol is rather obtained. The ul trasonic activation has been studied as regards the faradaic yield and the chemical selectivity. This work puts into evidence the interest of ultrason ication for electroorganic synthesis processes often submitted to passivati on phenomena. (C) 2000 Elsevier Science Ltd. All rights reserved.