Post-synthesis and catalytic performance of FER type sub-zeolite Ti-ECNU-8

A titanosilicate Ti-ECNU-8 with a FER type sub-zeolite structure was developed by pots-synthesis and applied to the epoxdiation of alkenes with hydrogen peroxide. A controlled acid treatment on the pure silica layered precursor PLS-3 of FER topology gave rise to a sub-zeolite ECNU-8. Composed of a collection of FER sheets without an ordered stacking manner along layer related [1 0 0] direction, the structure of ECNU-8 was constructed by a reorientation of interlayer hydrogen bond moieties caused by partial removal of interlayer organic structure directing agent. ECNU-8 possessed an external surface area enlarged by ca. 30% in comparison to corresponding three-dimensional FER zeolite. Through a solid-gas reaction with TiCl₄ vapor, tetrahedral Ti active sites were introduced into the framework. The resultant Ti-ECNU-8 retained the structural properties of ECNU-8, and exhibited an excellent catalytic performance for the epoxidation of cycloalkenes owing to the accessible Ti sites located in open reaction space.