Synthesis of Titanium-Incorporated MWW Zeolite by Sequential Deboronation and Atom-Planting Treatment of ERB-1 as an Epoxidation Catalyst

A novel titanosilicate zeolite was synthesized by a sequential treatment of ERB-1 with deboronation and atom-planting method to develop an epoxide catalyst. The Fourier transform infrared (FTIR) and the diffuse reflectance infrared Fourier transform (DRIFT) characteristic results reveal that the silanol hydroxyl nests generated by deboronation process are further consumed by the dehydrochlorination of TiCl4 during the atom-planting treatment. At the same time, the titanium species are incorporated into the framework of MWW structure. The energy-dispersive spectroscopy (EDS), ultraviolet-visible light (UV-vis), and ultraviolet resonance Raman spectroscopy (UVRRS) characterization results reveal that the amount and coordination states of the incorporated Ti species can be controlled by the atom-planting treatment time and temperature. The catalytic performance of the new titanosilicates in the epoxidation of 1-hexene with H2O2 and of cyclohexene with tert-butyl hydroperoxide is compared for the efficiency of Ti species in the hydrophilic and hydrophobic system. The catalytic results show the framework tetrahedral coordinated titanium species are more efficient for epoxidation than extra-framework octahedral Ti species.