Electrosynthesis of toluidines using thermally coated Ti/TiO2 electrodes

Cyclic voltammetric and preparative scale investigations on the electroreduction of (o-nitrotoluene (ONT), m-nitrotoluene (MNT), p-nitrotoluene (PNT) and 2,4-dinitrotoluene (DNT) to their corresponding toluidines in 1 M H2SO4 using thermally coated Ti/TiO2 electrode are reported. In the cyclic voltammetric time scales inhibitive adsorption which decreased in the order ip ONT>ip MNT>ip PNT>ip DNT was noticed. The heterogeneous redox catalytic currents were also found to decrease in the same order. In preparative electrolysis, these inhibitive effects became unimportant. Yields around 90% were achieved for all four nitro compounds. The thermally coated Ti/TiO2 electrode could be reused at least five times without any loss in yield and current efficiency.