Recent advances in MWW-type titanosilicates

The progress in the preparation, structure modification, and catalytic applications in liquid-phase selective oxidations of MWW-type titanosilicates is reviewed. A novel titanosilicate with the MWW topology, Ti-MWW, has been prepared by various methods such as hydrothermal synthesis using boric acid as a crystallization-supporting agent, dry gel conversion, postsynthesis through reversible structural conversion, and dual structure-directing agents method. Ti-MWW, originating from a lamellar precursor, is readily subjected to various structural modifications, which leads to the catalytic materials with larger porosity suitable for a variety of oxidations. The unique pore and structure properties of Ti-MWW make it to be active and selective for the epoxidation of both linear and cyclic alkenes. Moreover, exhibiting a different solvent effect to TS-1, Ti-MWW shows more advantages in product selectivity in the ammoximation of ketones and epoxidation of alkenes with functional groups.