Electrochemical Reduction of AQ27DS in Aqueous Solution


Article Preview

It is known that anthraquinone derivatives act as aqueous sulphide oxidation catalysts, so the redox chemistry of the compound anthraquinone 2,7-disulphonate (AQ27DS) stimulated our interest, as reported here. AQ27DS was reduced in aqueous solution at pH 9.0 to give a deep red coloured air-sensitive solution. Cyclic voltammetry and exhaustive electrolysis indicated that the anthraquinone was reversibly reduced in a two electron, one proton process at a variety of electrode surfaces. From limiting current results at a rotating disc electrode, the diffusion coefficient of AQ27DS was calculated to be 3.37 x 10-10 m2 s-1. Spectroscopic results confirmed that AQ27DSH- was the major reduced species, but also indicated that the di-anion (AQ27DS2-) and radical species AQ27DS• were also present. ESR spectroscopy showed that the radical was formed via a comproportionation reaction between the di-anion and the AQ27DS starting material. The peak separation from voltammetry enabled the comproportionation constant (Kc) to be estimated, and it was found to be in the range of 0.4 to 4.



Materials Science Forum (Volumes 514-516)

Edited by:

Paula Maria Vilarinho




C. A.C. Sequeira et al., "Electrochemical Reduction of AQ27DS in Aqueous Solution", Materials Science Forum, Vols. 514-516, pp. 1338-1342, 2006

Online since:

May 2006




[1] A. Heyrovsky, B. Kuta: Principles of Polarography (Academic Press, New York 1966, p.181).

[2] D. H Angell, T. Dickinson: J. Electroanal. Chem. Vol. 35 (1972), p.55.

[3] R.C. West, ed.: CRC Handbook of Chemistry and Physics (CRC Press Inc., Florida, USA 1983, p. F-46).

[4] C.A. C Sequeira, R.F. Lobo, G. Anastassakis: Proc. 1st Int. Conf. on Diffusion in Solids and Liquids, DSL-2005 (Univ. Aveiro, 2005), p.655.

[5] M.A.G. Martins and C.A.C. Sequeira: Técnica Vol. 1/84 (1984), p.47.

[6] A.J. Bard, L.R. Faulkner: Electrochemical Methods: Fundamentals and Applications (John Wiley and Sons, New York 1980, p.218).

[7] D.E. Richardson, H. Taube: Inorgan. Chem. Vol. 20 (1981), p.1278.

[8] D.S. Polcyn, I. Shain: Analytical Chemistry Vol. 38 (1966), p.370.

[9] G.H. Kelsall, I. Thompson: J. Appl. Electrochem. Vol. 23 (1993), p.296.

[10] R.G. Compton: Electrochemical ESR, Ph.D. Thesis (Chem. Dept. Univ. Oxford, 1980).