Preparation and application of highly dispersed gold nanoparticles supported on silica for catalytic hydrogenation of aromatic nitro compounds

Highly dispersed gold nanoparticles supported on silica were successfully prepared by a novel and simple in situ reduction technique that makes use of the 3-glycidoxypropyl group, CH2CH2CH2OCH2CHCH2O, on modified silica as reductants. In the new procedure, the organic groups are introduced onto silica via a sol–gel process of tetraethyl orthosilicate (TEOS) and 3-glycidoxypropyl-trimethoxysilane (GPTMS) assisted by ammonia water, with gold nanoparticles uniformly in the range 7.0–9.0 nm. The silica-supported gold nanoparticles were evaluated for the liquid-phase catalyze reduction of various aromatic nitro compounds by molecular hydrogen, and their corresponding amines with high chemoselectivity were obtained under the reaction conditions of 140 °C, 4.0 MPa, and 2.5–5 h, particularly for chloronitrobenzenes, the undesirable dechlorination reactions could be avoided completely.