Synthesis of bimodal mesoporous titanosilicate beads and their application as green epoxidation catalyst

Abstract Bimodal mesoporous titanosilicate beads with interconnected three-dimensional pore architecture (BMB-TiSil) were synthesized through a one-pot dual-templating method in the presence of a porous anion-exchange resin. Whereas the framework mesopores centered at 3.5 nm are generated by the templating effect of the surfactant, the continuous large mesopore system originates from removal of the resin body. In the green epoxidations of alkene with aqueous H 2 O 2 , BMB-TiSil showed higher turnover frequency (TOF) based on the alkene conversion and higher epoxide yield than Ti-MCM-41, which is mainly ascribed to the continuous large mesopore system favoring the diffusion of the reactants and products to and from the active titanium sites. Importantly, BMB-TiSil is a stable catalyst immune to titanium leaching, and can be reused in three successive catalytic cycles without significant loss of activity due to its continuous large mesopore system and stable Ti-sites.