Selective oxidation with copper complexes incorporated in molecular sieves

Abstract

The selective oxidation, with molecular dioxygen as well as aqueous H2O2, of n-hexane, naphthalene and phenols using complexes of copper (copper acetate, copper phthalocyanine, copper chlorophthalocyanine and copper nitrophthalocyanine) encapsulated in molecular sieves (X, Y, MCM-22 and VPI-5) is reported. The integrity of the copper complexes in the cavities of the molecular sieves was confirmed by IR, UV-VIS, ESCA and ESR spectroscopic techniques. Dimeric copper acetate complexes encapsulated in molecular sieves oxidise phenols to ortho diphenols and diphenols to quinones using O2 as the oxidant. Encapsulated chloro- and nitro- phthalocyanines oxidise n-hexane selectively to 1-ol and 1-al using molecular oxygen and to 2-ol and -on, 3-ol and -on using aqueous H2O2 as the oxidants, respectively. Similar oxidation of naphthalene yields beta naphthol with high selectivity using H2O2 as the oxidant. The copper phthalocyanines, encapsulated in the zeolites Na-X or Na-Y, oxidise phenols to hydroquinone and catechol with high efficiency. Copper complexes encapsulated in molecular sieves are a promising class of selective oxidation catalysts.