Oxidation of cyclohexane with molecular oxygen using heterogeneous silica gel catalyst bonded with [1,2-bis(salicylidene amino)-phenylene] zirconium complex

A heterogeneous catalyst prepared by chemically binding [1,2-bis(salicylidene amino)-phenylene] zirconium complex to modified carbamated silica gel catalyst has been synthesized. This binding of the complex with silica gel has been demonstrated by carrying out the same reaction with a small molecular homologue compound t-butanol, modified similarly. The oxidation of cyclohexane using molecular oxygen was studied and the product distribution was found to be entirely different from that reported in the literature. The product distribution consisted of cyclohexanol (major product) together with small amounts of cyclohexene in the ratio 6.6:1. At 200degreesC, the conversion was 21% and cyclohexanol was formed with a selectivity of 73%. The thermogravimetric analysis shows that the catalyst is unstable only beyond 383degreesC. (C) 2004 Published by Elsevier B.V.