Ordered mesoporous titanosilicates with better catalytically active titanium sites assembled from preformed titanosilicate precursors with zeolite building units in alkaline media

摘要: Mesostructured titanosilicates have been successfully synthesized from the assembly of preformed titanosilicate precursors with CTAB surfactant micelle in both alkaline media (MTS-5) and strongly acidic (MTS-8). The samples were characterized by powder X-ray diffraction (XRD), nitrogen isotherms, 29Si MAS NMR, IR, UV–visible spectroscopy. These materials exhibit highly hydrothermal stability, as compared Ti-MCM-41. Characterization results indicate that these mesostructured MTS-5 MTS-8 TS-1-like titanium species, mesoporous walls contain primary secondary building units similar to those microporous crystal TS-1 zeolite. In catalytic hydroxylation 2,3,6-trimethylphenol, show higher activities comparison material More importantly, assembled has silica condensation degree, media. After heating at 550 °C for 4 h, basically remains its phenol indicating stability Ti species calcination. contrast, calcined shows much lower conversion than as-synthesized MTS-8.