Collect. Czech. Chem. Commun. 2011, 76, 755-762
Published online 2011-05-26 08:15:05

A chronoamperometric study of the oxidative nucleation of niazid and isoniazid on mercury electrodes in basic solutions

Mercedes Ruiz Montoyaa, Sara Pintadob and José Miguel Rodríguez Melladob,*

a Departamento de Ingeniería Química, Química Física y Química Orgánica, Universidad de Huelva, Campus El Carmen, Facultad de Ciencias Experimentales, E-21071 Huelva, Spain
b Departamento de Química Física y Termodinámica Aplicada. Universidad de Córdoba, Campus Universitario de Rabanales, edificio “Marie Curie”, E-14014 Córdoba, Spain


Using chronoamperometric measurements at pH 12 it is shown that the oxidation mechanism of niazid adsorbed on the mercury electrode changes with respect to the mechanism reported in the literature for the electrooxidation of the molecules reaching the electrode by diffusion. A compact monolayer of niazid molecules is formed on the electrode surface, being the hydrazide oxidized through a two-electron process. The oxidation product is not able to dissociate a H+ ion, and the oxidation process does not proceeds beyond. For isoniazid the monolayer never becomes compact.

Keywords: Pyridine hydrazides; Niazid; Isoniazid; Oxidation; Nucleation; Electrode kinetics; Adsorption; Electrochemistry.

References: 16 live references.