Electrocatalytic hydrogenation of azobenzene and nitrocyclohexane with dispersed cooper microparticles into poly(pyrrole-alkylammonium) films

This paper presents the results of the electrocatalytic hydrogenation of azobenzene and nitrocyclohexane on carbon felt cathodes modified by poly(pyrrole-alkylammonium) films and containing dispersed metallic copper microparticles in a hydroorganic medium at neutral and basic pH. The effect of the polymers’ structures, the cathode nature, and the effect of synthesis methods on the electrocatalytic activity of the electrodes have been examined, as well. The obtained products were identified by gas chromatography in comparison with authentic ones. It is found that azobenzene leads to aniline, while nitrocyclohexane to cyclohexanone oxime. Indeed, these cathodes allow the hydrogenation of the substrates at potentials between -1 and -1.2 V/SCE in basic medium and between -0.65 and 0.85 V/SCE in neutral medium, lower as compared with their reduction potentials. It is indicated that the best chemical and electrical yields are obtained in a basic medium and the chemical yields of the formed products increase with the amount of copper inserted, while the length of the alkylammonium chain has no remarkable influence on yields. It has been demonstrated that these cathodes have a good electrocatalytic activity despite the very small amount of copper inserted into the polymer film.