Manganese porphyrins as catalysts for oxidation of cyclooctane in Lyons system

Oxidation of cyclooctane with molecular oxygen (as air) in the presence of first generation manganese porphyrins XMn(III)(TTP), where X=F(-), Cl(-), Br(-), I(-), OH(-), CH(3)COO(-), as catalysts was investigated in the Lyons system. The catalytic activities of the metalloporphyrins in the oxidation of cyclooctane to cyclooctanone and cyclooctanol are covariant with electronegativity of halides as axial ligands and increase with the decrease of the redox potential of metalloporphyrins. It was concluded that axial ligands are involved in the reaction initiating the reaction by generating the radicals with simultaneous reduction of the manganese porphyrin. Relatively high yields of products were obtained without the use of sacrificial co-reductant. (C) 2000 Elsevier Science B.V. All rights reserved.