An Efficient and Reusable Catalyst of Bismuth-Containing SBA-15 Mesoporous Materials for Solvent-free Liquid Phase Oxidation of Cyclohexane by Oxygen

摘要

Bismuth-containing SBA-15 mesoporous materials with different n_(si)_(Bi) ratio was synthesized for the first time through a direct hydrothermal method, and characterized by various physico-chemical techniques. XRD patterns indicate that the synthesized materials have an ordered two-dimensional p6mm hexagonal mesostruc-ture. Transmission electron microscopy and scanning electron microscopy studies show that Bi-SBA-15 has well-ordered hexagonal arrays of mesoporous channels and the morphology of rod-like particles. Raman spectroscopy and UV-Vis DRS show that bismuth atoms in Bi-SBA-15 exist in a highly dispersed state, and locate mainly at tet-rahedrally coordinated sites. Thermogravimetric analysis was used to observe the removal of the organic template P_(123). In the catalytic test, Bi-SBA-15 is found to be a very efficient and reusable catalyst for the oxidation of cyclohexane, in a solvent-free system, with oxygen as oxidant. The influence of different parameters, such as reaction time, reaction temperature, oxygen pressure, and the dosage of catalyst on the oxidation of cyclohexane, is also investigated.