Silica-supported palladium nanoparticles show remarkable hydrogenation catalytic activity

Palladium nanoparticles (1.9 nm) stabilized on silica were obtained from the reduction of an organometallic precursor (palladium(II) bis-dibencylidene acetone) with dihydrogen. This material was investigated in the hydrogenation catalysis of different substrates (1-hexene, cyclohexene, benzene, 2-hexanone, cyclohexanone and benzonitrile). The solid was used as a heterogeneous catalyst. The highest hydrogenation rate was found with 1-hexene with a TOF of 38,250 mole of product/(mole of metal/h) at 25degreesC and 30 psi pressure. The [Pd/SiO2] nanocatalyst has shown remarkably high activity for the catalytic hydrogenation of cyclohexene (TOF 33,000) and benzene (TOF 10,000). This is the first reported palladium nanocatalyst with high catalytic activity towards the hydrogenation of 2-hexanone TOF 16,000, cyclohexanone TOF 15,000 and benzonitrile TOF 5000 reported to the date. (C) 2002 Elsevier Science B.V. All rights reserved.