Synthesis of TS-1 in fluoride medium. A new way to a cheap and efficient catalyst for phenol hydroxylation

Abstract

Titanium silicalite-1 (TS-1) was synthesized by two different methods in fluoride medium. The preparation of a sol or a gel containing SiOTi bonds prior to fluoride addition is the key step of the synthesis. Characterization of the samples by X-ray diffraction, infrared and diffuse reflectance ultraviolet–visible spectroscopies, and elemental analysis confirms that the titanium species are essentially located in framework positions. The size of the crystals depends on the synthesis variables. In the presence of seeds, small crystallites (<2 μm) are obtained. The corresponding samples exhibit high activity and selectivity for phenol hydroxylation by H 2O 2, similar to TS-1 prepared in the presence of tetrapropylammonium hydroxide.