Rate enhancement of oxidation reactions by the encapsulation of metal phthalocyanine complexes

Iron phthalocyanine (FePc) and cobalt phthalocyanine (CoPc) as free complexes as well as encapsulated in zeolite-Y (FePc-ZeY and CoPc-ZeY) have been studied as catalysts in mild, aerobic oxidation of hydroquinone. A remarkable rate enhancement was observed with the encapsulated catalysts, especially in the case of the encapsulated cobalt phthalocyanine, where the encapsulated complex was a good, active oxidation catalyst, while its homogeneous analogue was completely inactive. The site isolation effect is responsible for the observed rate enhancement. The solvent effect was also studied in the case of free complexes and encapsulated catalysts.