An efficient hydrophobic modification of TS-1 and its application in the epoxidation of propylene

Abstract

The poor hydrophobic properties of titanium silicalite-1 (TS-1) lead to by-product formation and catalyst deactivation. In the present study, with the goal of preventing the generation of by-products and improving the reaction selectivity, hydrophobic TS-1 (HTS-1) with uniform intracrystalline micropores has been successfully synthesized through one-step hydrothermal techniques with the assistance of resole resin precursors as the carbon source. The crystal and skeleton structure, pore properties, thermal stability, hydrophobic properties, and surface morphology of TS-1 and HTS-1 were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), ultraviolet-visible spectroscopy (UV-vis), N₂ adsorption–desorption isotherm analysis, thermogravimetric analysis (TG), contact angle measurements, transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The effects of different silicon to carbon molar ratios in the synthesis of HTS-1 catalysts were investigated. The catalytic activity of HTS-1 with different Si/C molar ratios in propylene epoxidation has been examined in detail. The results showed that HTS-1 zeolites exhibited remarkable hydrophobicity and showed outstanding selectivity in propylene epoxidation compared to conventional TS-1 zeolites.