Synthesis and characterization of the highly reactive vanadium oxide species supported on mesoporous silica for the hydroxylation of benzene

摘要

Highly reactive VO_x catalysts supported on aluminum substituted mesoporous and microporous silica (MPS) were prepared by the molecular designed dispersion (MDD) method. The formation of octahedral vanadium oxide samples possess much removable mobile ligands in the catalytic center that could be easily substituted by hydrogen peroxide and yielded the active peroxo intermediate for further hydroxylation of benzene. We also prepared tetrahedral vanadium oxide catalysts by the coordination of V~V center with mono-, di-, and tri-amine modified SiO_2. The tetrahedral coordination of vanadium oxide catalysts showed less mobile ligands in the catalytic medium and yielded lower activity toward the hydroxylation of benzene.