Benign oxidants and single-site solid catalysts for the solvent-free selective oxidation of toluene

Two types of single-site heterogeneous catalysts have been designed so as to facilitate either the side-chain oxidation or ring-hydroxylation of toluene in O2 (solvent-free) or by employing aqueous (H2O2) or organic (cumene hydroperoxide) hydroperoxides in high yield. The use of H2O2 and cumene hydroperoxide in particular, facilitates the ring-hydroxylation of toluene when zeolite-encapsulated metal complexes, such as perhalogenated or tetra-nitro-substituted phthalocyanines, are used as catalysts. Nanoporous, redox molecular sieves, display a higher tendency for the side-chain oxidation of toluene with air as an oxidant, with benzoic acid as the predominant product.