Synthesis, characterization and catalytic testing of a 3-D mesoporous titanosilica, Ti-TUD-1

An active and stable mesoporous titanosilica, denoted as Ti-TUD-1, has been synthesized using a cheap, small and multifunctional chemical, triethanola mine (TEA), instead of surfactants. TEA not only is applied as a mesopore t emplate and as a director of positioning Ti-sites onto the internal mesopor e surface via the formation of titanium-TEA complexes, but also stabilizes titanium sources, which ensures the possibility of forming isolated tetrahe drally coordinated Ti-sites. Ti-TUD-1 features three-dimensionally randomly connected mesopores with walls of about 2.5-4 nm in thickness. Its surface area can reach about 700-1000 m(2)/g and its pore sizes are tunable. After calcination at 1000 degreesC and boiling in water, it kept a high integrit y, a high surface area and only a slight change in pore sizes occurred. UV- VIS spectra revealed that tetrahedrally co-ordinated Ti-sites are quite sta ble under thermal and hydrothermal treatments. It also showed about 5.6 tim es higher activity for cyclohexene epoxidation than the framework-substitut ed Ti-MCM-41 and similar activity compared to Ti-grafted MCM-41. (C) 2001 E lsevier Science B.V. All rights reserved.