Pyridine-4-ylmethyl-propyl-amine-organomodified HMS as support for in situ formed cobalt complexes-influence of the metal source on structure and catalytic activity in the aerial epoxidation of olefins

In this paper we compare the properties and catalytic activities of immobilised forms of in situ formed cobalt complexes of pyridin-4-ylmethylpropyl-amine (PYPA), immobilised via grafting of pyridin-4-ylmethyl-(3-triethoxysilanyl-propyl)-amine on pre-formed HMS, and various cobalt salts, formed in aqueous solution. To investigate the role of peroxo species on the catalytic activity, materials with cobalt-alkyl- or hydroperoxo groups were also prepared by addition of TBHP or H2O2 in the loading step of the preparation. The support material and the catalysts were characterised by STA, DRUV, and N-2 adsorption. All catalysts are active in the aerial oxidation of styrene and, with few exceptions, 1-decene, and exhibit different reactivities and selectivities towards epoxidation. (C) 2003 Elsevier B.V. All rights reserved.