The heterogenization of an active homogeneous ruthenium oxidation catalyst on silica has been studied. The ligand 2-(phenylazo)pyridine has been covalently linked onto silica and a ruthenium complex with this anchored ligand has been characterized by elemental analysis, CP MAS C-13 NMR and DRIFT infrared. The obtained catalysts appeared to be active for the epoxidation of trans-stilbene, and the catalytic activity and the selectivity were found to be dependent on the cooxidant. The best results were obtained with a catalyst having a ruthenium to ligand ratio of 1.1 to 1.0 and when dioxygen/isobutyraldehyde was used as cooxidant; in that case, after 24 hours at 40 degrees C, 96% conversion of trans-stilbene was found, with 95% selectivity for the epoxide. The catalysts were also found to be active for alcohol oxidation. Cyclobutanol was oxidized to cyclobutanone and acyclic products, indicating both a two- and a one-electron oxidation pathway. 1,2-Cyclohexanediol could almost quantitatively be convened to adipic acid. The immobilized catalysts have also been used for the oxidation of octyl alpha-D-glucopyranoside to octyl alpha-D-glucuronic acid. However, for this reaction the corresponding homogeneous ruthenium catalyst was found to be more selective than the heterogenized catalyst. Recycling of the immobilized catalyst for the oxidation of n-butanol showed that a catalyst in which the amine function is methylated is more stable than a catalyst with a secondary amine; in that case a coordinated ruthenium is lost easier. The catalyst with the methylated amine function retains its high oxidation reactivity over at least 4 oxidation cycles.