Study on the synthesis and the catalytic properties of Fe-HMS materials in the hydroxylation of phenol

A series of Fe-HMS mesostructure materials were synthesized at ambient temperature using alkylamines as the structure director. The Fe-HMS materials were characterized by XRD, DRS UV–Vis, ICP-AES, TEM and N2 adsorption. The effects of the synthesis conditions, such as the ratio of Fe/Si, chain length of surfactant, the surfactant/SiO2 ratio, synthesis time, usage of isopropyl alcohol, the H2O/SiO2 ratio and the ethanol/SiO2 ratio on the textural properties of the Fe-HMS materials were investigated. The results show that the incorporation of iron ions into the framework of HMS material is mainly tetrahedrally coordinated. After the synthesis solution was aged for 3 h Fe-HMS mesostructure has formed, and the pore structure of Fe-HMS materials is affected hardly by the synthesis time. The pore diameter of Fe-HMS can be modified by changing the chain length of surfactant and the ratios of Fe/Si, H2O/SiO2 and ethanol/SiO2. The presence of isopropyl alcohol in the synthesis gel helps to the successful synthesis of the Fe-HMS materials. The Fe-HMS mesostructure material is a highly efficient catalyst for the hydroxylation of phenol in the fixed-bed reactor.