Synthesis of Novel Titanosilicate Catalysts by Simultaneous Isomorphous Substitution and Interlayer Expansion of Zeolitic Layered Silicates

A facile and cheap method for the postsynthesis of large-pore titanosilicates from layered zeolitic silicate precursors is presented, in which isomorphous substitution of Ti for Si and interlayer expansion with mobile Si debris are realized simultaneously using aqueous H₂TiF₆ solution at room temperature. This versatile and convenient one-pot postsynthesis was used to construct several different 3D interlayer-expanded zeolite (IEZ) structures with tetrahedrally coordinated Ti incorporated into the framework without the use of external silane. The structural transformation and the incorporation of Ti in the preparation of IEZ-Ti-PLS-3 were monitored using Rietveld refinement and NMR studies. Furthermore, IEZ-Ti-PLS-3 exhibited unique catalytic properties in the epoxidation of alkenes with hydrogen peroxide, and was active not only for linear alkenes but also for bulky cyclic alkenes.