Aerobic epoxidation of olefins catalyzed by Co-SiO2 nanocomposites

Cobalt-silica nanocomposite catalysts have been prepared using sol-gel process followed by drying under different conditions. The use of amino functionalized silane in the gelation step provided homogeneous distribution of the cobalt through the whole material. TEM, XPS and H-2-TPR data reveal that highly dispersed cobalt(II) sites are present in the samples. The catalysts were evaluated for selective aerobic epoxidation of olefins without the use of sacrificial reductant. Among the Co-SiO2 nanocomposite catalysts, aerogel prepared catalyst has shown superior activity due to the high porosity clubbed with highly accessible cobalt(II) sites. (c) 2007 Elsevier B.V. All rights reserved.