Titanosilicate composite with zeolite-large-crystal core and mesoporous shell structures: One-step synthesis and application in catalytic oxidations

摘要

Porous titanosilicate composite with a core/shell structure and tetrahedral Ti species was synthesized by one-step process in fluoride medium, in which a mixture of small organic ammonium salt and cationic polymer was used as template. The composite displayed higher activity than the TS-1 large crystals prepared without cationic polymer in the epoxidation of cyclohexene with aqueous H_2O_2 and tert-butyl hydroperoxide, mainly ascribed to the improved accessibility of reactants to the active sites via the mesopores in the shell. Notably, the composite can be easily separated from the reaction solution thanks to its large crystal format.