Cationic metalloporphyrins and other macrocyclic compounds in zeolite matrix as catalysts for oxidation with dioxygen

Syntheses and catalytic activity of the cationic iron, manganese, cobalt porphyrins, cobalt salen and cobalt phthalocyanine in homogeneous reaction and these metallocomplexes entrapped inside zeolite NaX supercages have been studied in oxidation of cyclooctane with dioxygen (as air) to cyclooctanone and cyclooctanol without the use of sacrificial co-reductant. We have found that activity of free cobalt complexes increases in the order CoPorphyrin, CoSalen and CoPc, the latter being five times more active than the first one. CoPorphyrin after immobilization inside zeolite X increases its activity, whereas CoSalen and CoPc slightly decrease the activity. The catalytic activity of Mn and Fe complexes changes only to a small extent after encapsulation. The type of the macrocyclic ring and the type of metal determine the product yields and the selectivity to cyclooctanone and cyclooctanol which are strongly modified by encapsulation in the zeolite matrix. The results represent the first example of catalytic application of metallocomplexes encapsulated inside the zeolite structure for oxidation of hydrocarbons with dioxygen under high pressure and temperature without the use of sacrificial co-reductant. (C) 2004 Elsevier B.V. All rights reserved.