One-pot synthesis of cobalt-salen catalyst immobilized in silica by sol–gel process and applications in selective oxidations of alkanes and alkenes

Salen ligand prepared from 1,2-phenylenediamine and 2-hydroxy-3(3-triethoxysilyl-propyl)-benzaldehyde has been used as cobalt-chelate for the immobilization of the catalytic site by a one-pot synthesis method. Sol–gel hydrolysis and polycondensation of this chelate with 10 equivalents of tetraethyl orthosilicate produced the heterogeneous catalyst. This catalyst is active in selective molecular oxygen oxidations of cyclohexane, cyclohexene, toluene, styrene and anthracene in the presence of butyraldehyde at room temperature.