Oxyhalogenation of aromatics over copper phthalocyanines encapsulated in zeolites

Abstract

The oxychlorination and oxybromination, under near-ambient conditions, of benzene, toluene, phenol, aniline, anisole, and resorcinol, using as catalysts the phthalocyanines of Cu, Fe, and Co encapsulated in zeolites X, Y, and L, are reported. Both H₂O₂ and O₂ have been used as oxidants. HCl and alkali chlorides/bromides have been used as sources of halogens. The metal phthalocyanines wherein the aromatic rings are substituted by -Cl or -NO₂ groups are more active. There is a dramatic increase in the turnover frequencies for substrate conversion when the complexes are encapsulated in the cavities of the zeolites X, Y, or L. The oxyhalogenation of both the aromatic nucleus and the alkyl side chains occur. Oxidation of the aromatic ring (to phenols or cresols, for example) does not occur. Alkyl side chains, however, are oxidized by the oxidant H₂O₂ or O₂ to alcohols, ketones, and acids. The performance of these novel catalyst systems as solid oxyhalogenation catalysts in utilizing O₂ and halide ions in the manufacture of halogenated aromatics holds promise in the organic chemicals industry.