Oxidation of aromatic compounds by hydrogen peroxide catalyzed by mononuclear iron(III) complexes

In the present work, four mononuclear iron(III) complexes containing BMPA (BMPA= bis-(2-pyridylmethyl)amine) and derivative ligands, have been studied as catalyst in toluene oxidation, at 25 degrees C and 50 degrees C, using hydrogen peroxide as oxidant and acetonitrile as solvent. All catalysts were able to oxidize toluene with satisfactory yields, producing o-, m-, p-cresols, benzaldehyde and benzyl alcohol, as main products, and traces of 2-methylbenzoquinone and benzoic acid. The catalyst [Fe(BMPA)Cl-3] presented the most promising results, reaching yields up to 30.2% at 50 degrees C after 24 h. Furthermore, [Fe(BMPA)Cl-3] was applied in the oxidation of other aromatic compounds as benzene, ethylbenzene, cumene, n-propylbenzene, p-xylene and anisole. The reaction with H2O2 was monitored by electronic UV-vis spectroscopy in the presence and absence of toluene and its oxidation products, as well as by ESI-(+)-MS/Q-TOF mass spectrometry, in order to provide some information about the reaction mechanism. (C) 2016 Elsevier B.V. All rights reserved.