Olefin oxidation with dioxygen catalyzed by porphyrins and phthalocyanines intercalated in α-zirconium phosphate

Oxidation of cyclohexene and cis-stilbene with dioxygen in presence of metal phthalocyanines or metal tetraphenylporphyrins complexes intercalated in alpha -zirconium phosphate and isobutyraldehyde were studied. The degradation of free metal complexes in solution in the reaction media was verified. It was observed that the matrix protects the metal complexes from degradation and the activity of the catalytic system is preserved. Oxidation of cyclohexene with intercalated complexes gave epoxide as the predominant product, while allylic oxidation products were obtained in smaller proportion and the product distributions depended on the identity of the individual metal complexes. Since the addition of a free radical inhibitor stops the reaction, a free radical mechanism should be present. Oxidation of cis-stilbene with intercalated metal complexes gives different ratios of cis- to trans-stilbene oxide and of benzaldehyde which depend on the intercalated metal complex, suggesting that in addition to the free radicals there is another active oxidizing agent. (C) 2001 Elsevier Science B.V. All rights reserved.