SYNERGISTIC EFFECT OF IRON AND COPPER OXIDES SUPPORTED ON SILICA IN THE ROOM-TEMPERATURE OXIDATION OF CYCLOHEXANE

The room temperature oxidation of cyclohexane with oxygen/zinc (Gif(IV ) system), catalysed by iron oxide supported on silica, has been studi ed. It was found that after calcination the iron catalyst does not lea ch and is very active for oxidation. Using 4 mmol of iron chloride per 0.1 g of silica, cyclohexanone and cyclohexanol (2:1 ratio) were obta ined with a turnover number of 425. Substitution of half of the iron u sed for impregnation by copper chloride increased the turnover number to 885, without changing the product ratio. As copper chloride alone i s not active for this reaction, it exhibits a synergistic effect on th e iron(III) heterogenized on the silica.