MWW-Type Titanosilicate Synthesized by Simply Treating ERB-P Zeolite with Acidic HTiF and Its Catalytic Performance in a Liquid Epoxidation of 1-Hexene with HO.

Synthesis of a Ti-incorporated zeolite using a simple and economical method has recently become a focus of attention. The direct hydrothermal synthesis of Ti-MWW is most commonly applied; however, it is challenging to perform and exhibits low titanium utilization. An innovative strategy of synthesizing Ti-MWW is proposed in the present study by simply treating the ERB-1 precursor of an MWW-type boron silicate with a HTiF/HNO solution. This significantly shortens the Ti grafting process from 5 days to only a few hours and reduces the use of the structure-directing agent hexamethyleneimine (HMI); furthermore, no extraframework Ti is observed in the precursor, indicating good atomic economy. Typically, a piperidine (PI)-treated sample Ti-MWW exhibits a higher conversion (76.6%) than the original Ti-MWW (44.8%) in the epoxidation of 1-hexene. X-ray diffraction (XRD), inductively coupled plasma (ICP), and transmission electron microscopy (TEM) techniques are used to explain in detail the probable mechanism underlying the incorporation of Ti species into the MWW framework. X-ray photoelectron spectroscopy (XPS) is employed to study the coordinate state of the Ti and F species in the samples after treatment with a piperidine solution. This method can be applied to synthesize other kinds of lamellar-structured zeolites with heteroatoms.