An in situ UV-vis and IR spectroelectrochemical study of the disposition of a hydroquinone anion salt on platinum electrodes from dichloromethane solutions (vol 441, pg 197, 1998)

Cyclic voltammetry with a platinum electrode of hydroquinone (BQH(2)) solut ions in dichloromethane, containing tetrabutylammonium perchlorate supporti ng electrolyte, shows a sharp asymmetric irreversible oxidation peak at abo ut -0.3 V (SCE). This feature is seen, in addition to the expected features in this system, when the cycle is extended to potentials more negative tha n -0.6 V (SCE). Cyclic voltammetry, in situ UV-vis and infrared spectroelec trochemistry have shown that hydroquinone anion (BQH(-)) is formed at negat ive potentials and this appears to arise via surface decomposition of hydro quinone to p-benzosemiquinone (BQH(.)) followed by reaction of BQH(.) with the p-benzoquinone radical anion (BQ(.-)). The sharp asymmetric peak in the cyclic voltammograms is due to oxidation of the hydroquinone anion in the insoluble tetrabutylammonium salt on the electrode surface. The oxidation o f BQH(-) appears to occur via disproportionation of (BQH(.)) and leads to B QH(2) and p-benzoquinone (BQ) as the products. (C) 1999 Elsevier Science S. A. All rights reserved.