Abstract

MARQUEZ, Olga P; MARQUEZ, Jairo; CABRERA, Wilmer  and  BORRAS, Carlos. Kinetics aspects of the electrooxidation of veratrole in wet acetonitrile. Rev. LatinAm. Metal. Mater. [online]. 2011, vol.31, n.1, pp.2-10. ISSN 0255-6952.

The electrooxidation of veratrole (1,2-dimethoxybenzene) at a platinum surface, was evaluated in dry and wet acetonitrile in tetrabutylammonium tetrafluoroborate, using in situ UV-Visible spectroelectrochemistry. As the content of water was increased, a competition between growth of polyveratrole and formation of soluble species (mainly 2,3- dimethoxybenzoacetamide) was observed. It was found that the decay rate of the cation radical formed during the electrooxidation in dry acetonitrile obeys a second order kinetics (k_f1 = 258 M^-1s^-1), involving a chemical step coupled to the first electron transference with growth of polyveratrole on the electrode surface. Under wet conditions, the decay rate constant of the cation radical follows a pseudo first order kinetics (k_f2 = 2.40 s^-1 when measured by differential reflectance spectroscopy, DRS, and k_f2 = 3.25 s^-1 when measured by absorbance determinations, AD), leading to formation of soluble species diffusing to the bulk

Keywords : Polyveratrole; Oxidation of veratrole; Electrooxidation; Conducting polymers; Electropolymerization.