Hydrophobic fluorinated TiO2–ZrO2 as catalyst in epoxidation of 1-octene with aqueous hydrogen peroxide

Hadi Nur, Universiti Teknologi Malaysia
Ng Yun Hau, Universiti Teknologi Malaysia
Izan Izwan Misnon, Universiti Teknologi Malaysia
Mohd Nazlan Mohd Muhid, Universiti Teknologi Malaysia
Halimaton Hamdan, Universiti Teknologi Malaysia

Abstract

A new heterogeneous oxidation catalyst was prepared by impregnation of TiO2 from titanium(IV)tetra-2-propoxide on the surface of ZrO2. The surfaces of TiO2–ZrO2 particles were then modified by the fluorination of ammonium hexafluorosilicate and followed by alkylsilylation of n-octadecyltrichlorosilane (OTS). The resulting catalysts were characterized by X-ray diffraction (XRD), nitrogen adsorption isotherm, UV–Vis Diffuse Reflectance (UV–Vis DR), and Energy Dispersive X-Ray Analysis (EDAX) techniques. The catalytic potential of catalysts for oxidation reactions has been verified in the liquid phase epoxidation of 1-octene to 1,2-epoxyoctane with aqueous hydrogen peroxide. It is demonstrated that the fluorination and alkylsilylation enhance the catalytic activity of TiO2–ZrO2. A high catalytic activity of the modified TiO2–ZrO2 was related to the modification of the local environment of titanium active site and increasing the hydrophobicity of catalyst particles by fluorination and alkylsilylation.