Reactivity of electrophilic oxygen species generated over mesoporous iron-containing catalysts

The vapour phase hydroxylation of toluene and epoxidation of propene and 1-butene with nitrous oxide over Fe/SBA-15 catalysts was experimentally investigated. Modification of these mesoporous catalysts by the addition of KCl resulted in a significant transfer from benzylic/allylic oxidation towards aromatic/vinylic oxidation by suppressing the reactivity of nucleophilic oxygen species. Analogous to the Fe/ZSM-5 system, highly dispersed iron species residing within the pore structure are responsible for generating the electrophilic oxygen species upon nitrous oxide decomposition. While substrate conversions are generally low (<4%), the catalysts offer phenolic/epoxide selectivities of ∼70% in an environmentally benign one-step reaction.