Titanosilicate beads as versatile catalysts for the conversion of trioses to lactates and for the epoxidation of alkenes

Titanosilicate beads with hierarchical porosity (TiSil-HPB-60) were prepared from an anion-exchange resin and proved to be a versatile heterogeneous catalyst displaying activity both in the conversion of trioses to ethyl lactate and in the epoxidation of alkenes. In the former reaction, TiSil-HPB-60 showed higher catalytic activity compared to two well-known titanosilicate catalysts: the crystalline microporous TS-1 and the ordered mesoporous Ti-MCM-41. Notably, TiSil-HPB-60 displayed significantly high selectivity towards ethyl lactate due to the absence of strong Brønsted acid sites. In the epoxidation of alkenes with aqueous H2O2, TiSil-HPB-60 displayed improved epoxide yield compared to TS-1 and Ti-MCM-41 when the bulky cyclohexene was used as substrate, while TS-1 was the most active catalyst with the linear 1-octene. In both reactions, the separation of TiSil-HPB-60 from the reaction mixture is very straightforward, thanks to its bead format, and the catalyst can be reused in successive catalytic cycles without significant loss of activity.