Synthesis of framework-substituted Fe-HMS and its catalytic performance for phenol hydroxylation

The iron-incorporated mesoporous silica material Fe-HMS was successfully synthesized at ambient temperature by using dodecylamine as the template agent, and it was characterized by XRD, SEM, FT-IR, UV-vis, ESR and N-2 adsorption measurements. Its catalytic performance was studied for phenol hydroxylation with H2O2 in a fixed-bed reactor. The results show that Fe3+ ions have been successfully incorporated into the framework of HMS, and Fe-HMS has a uniform mesoporous structure with about 2.7 nm pore diameter. After Fe-HMS is calcined, most of the Fe3+ ions remain in the tetrahedral coordinated framework, and only a small part of Fe species migrate to the extraframework. Fe-HMS has high catalytic activity and very high selectivity to dihydroxybenzene for the hydroxylation of phenol. Over the Fe-HMS catalyst, the product distribution of phenol hydroxylation is different from that over the microporous TS-1 zeolite. The solvents have great influence on the catalytic activity of Fe-HMS, and water is the best solvent.