Zeolite encapsulation of Cu clusters for the enhancement of catalytic selectivity in hydrogenation of p-nitrostyrene

Selective hydrogenation of nitroaromatics to anilines is a kind of important reaction in pharmacy industry and fine chemical engineering. However, this reaction is restrained by lack of catalysts and reaction system with high efficiency, energy saving, environmental protection and high selectivity. Herein, Cu nanoclusters were successfully encapsulated into Silicalite-1 zeolite by in-situ hydrothermal synthesis with ligand protection to obtain Cu@S-1 catalyst. The catalyst showed an excellent selectivity of 98 % with substrate conversion of 100 % in the hydrogenation of p -nitrostyrene to 4-vinylaniline using ammonia borane as hydrogen source, which was due to the preferential adsorption effect of Cu@S-1 catalyst on the nitro group. The Cu@S-1 catalyst also exhibits good recycling performance and substrate compatibility.