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 XMnIII(TTP), where X=F-, Cl-, Br-, I- , OH-, CH3COO-, as catalysts was investigated in the Lyons system. The cata lytic activities of the metalloporphyrins in the oxidation of cyclooctane t o cyclooctanone and cyclooctanol are covariant with electronegativity of ha lides as axial ligands and increase with the decrease of the redox potentia l of metalloporphyrins. It was concluded that axial ligands are involved in the reaction initiating the reaction by generating the radicals with simul taneous reduction of the manganese porphyrin. Relatively high yields of pro ducts were obtained without the use of sacrificial co-reductant. (C) 2000 E lsevier Science B.V. All rights reserved.