Electrolytic Conversion of Nitro Compounds into Amines in a Membrane Reactor

Aromatic and aliphatic amines are key intermediates in the synthesis of pharmaceuticals, dyes, and agrochemicals. These amines are often sourced from nitro compounds. The hydrogenation of nitro compounds into amines requires harsh reaction conditions (e.g., high pressures and/or high temperatures) or additives that are usually toxic. Here we demonstrate hydrogenation of nitro compounds into amines in the hydrogenation compartment of a membrane reactor. The hydrogen is sourced from water in an adjacent electrolysis compartment, separated by a hydrogen-permeable palladium membrane. Modifications of the palladium membrane with catalysts enabled a wide range of commercially relevant nitro compounds to be hydrogenated into amines without any additives at ambient pressure and room temperature. This membrane reactor also enables nitro hydrogenation to occur at high concentrations and with high functional group tolerance.