Delamination of Ti-MWW and high efficiency in epoxidation of alkenes with various molecular sizes

A new titanosilicate, named Del-Ti-MWW, has been prepared by delaminating the lamellar precursor of Ti-MWW, which is postsynthesized from highly deboronated MWW zeolite with the assistance of cyclic amine. The amount of organic base used for supporting surfactant in swelling the layered structure should be controlled carefully to delaminate efficiently without the collapse of the structure. Ultrasound treatment is demonstrated to delaminate the swollen material more completely. Del-Ti-MWW materials have a large surface area, which mitigates effectively the steric restrictions imposed by conventional microporous titanosilicates to bulky molecules. Del-Ti-MWW, maintaining the fundamental structure of MWW zeolite and tetrahedral Ti species in the framework position, proves to be superior to TS-1, Ti-Beta, three-dimensional Ti-MWW and even mesoporous Ti-MCM-41 in the epoxidation of a wide range of bulky alkenes with hydrogen peroxide.