Selective Catalytic Hydrogenation of Nitroarenes to Anilines

Selective catalytic hydrogenation of nitroarenes is of great importance for dyestuff and pharmaceutical industry. In this chapter, the main industrial methods for aniline production and aniline market are firstly reviewed. Moreover, breakthroughs in the development of multiple catalytic technologies in the past decade are summarized, including direct hydrogenation using hydrogen; transfer hydrogenation using reductive agents; photocatalytic hydrogenation using hole scavenger; electrocatalytic hydrogenation accompanied by water oxidation. For direct catalytic hydrogenation, representative catalysts include metal, metal oxide/sulfide/carbides/nitrides/boride, and functional carbon material, and the crucial factors to tune their activity and selectivity are discussed such as metal–support interaction, size effect, alloy effect, defect engineering, and so on. Catalytic transfer hydrogenation, photocatalytic and electrocatalytic hydrogenation, these catalysts abstract hydrogen species from the hydrogen donor and stabilizes it on the catalyst surface, restricting active H* recombination, and then the active hydrogen species can be promptly transferred to nitroarenes for the hydrogenation. It is worth mentioning that the light harvesting and charge separation of photocatalysts and the conductivity of electrocatalysts should also be considered together for the overall performance.