Excellent chemoselective hydrogenation of nitroaromatics and unsaturated aldehyde at the confined silver nanospace

Abstract

Catalytic reduction of nitroarenes and unsaturated aldehydes to corresponding hydrogenated products is an environment-friendly technology to prepare industrially important intermediates. however, high chemoselectivity still remains a big challenge when a nitroarene or unsaturated aldehyde molecule with two or more reducible groups. Herein, we construct a novel confined catalyst by encapsulating Ag NPs into the nanospace of hierarchical hollow silica (SiO2-Ag@void@SiO2), enabling the excellent chemoselective hydrogenation (>99%) of 2-nitrochlorobenzene and cinnamyl aldehyde into corresponding amino groups (-NH2) and hydroxyl groups (-OH) without hydrogenating other functional groups (-Cl and CC). The unique hydrogenation performance is identified to be associated with the confinement effect and highly dispersed Ag NPs because hydrogenation reaction takes place within the confined silver nanospace. Therefore, our study provides a guide to construct highly active catalysts for chemoselective catalysis.