Method for modifying titanium-silicon molecular sieve material

Abstract

The invention discloses a method for modifying a titanium-silicon molecular sieve material, which is characterized by comprising the following steps: adding titanium-silicon molecular sieve, silicon-containing compound, protective agent, reducing agent and noble metal source into solution containing alkali source, evenly mixing the mixture, then carrying out hydro-thermal treatment for the mixture in a closed reaction kettle, and reclaiming a product. The method improves the content of framework titanium, relatively reduces the content of the titanium on the outside surface and orifices of the molecular sieve by covering inert component silicon on the outside surface and the orifices of the titanium-silicon molecular sieve, and reduces the occurrence of side reaction on the outside surface and orifices of a molecular sieve catalyst so as to improve the oxidation activity, stability and target product selectivity of the modified titanium-silicon molecular sieve material at the same time of improving the synergistic action of noble metals and titanium-silicon molecular sieve materials.

Description

technical field [0001] The invention relates to a method for modifying a titanium-silicon molecular sieve material, in particular to a method for modifying the titanium-silicon molecular sieve material with a precious metal source. Background technique [0002] Titanium-silicon molecular sieve is a new type of heteroatom molecular sieve developed in the early 1980s. At present, TS-1 with MFI structure, TS-2 with MEL structure, MCM-22 with MWW structure and TS-48 with larger pore structure have been synthesized. Among them, the titanium-silicon molecular sieve TS-1 developed and synthesized by the Italian company Enichem is a new type of titanium-silicon molecular sieve with excellent catalytic selective oxidation performance formed by introducing the transition metal element titanium into the molecular sieve framework with a ZSM-5 structure. [0003] TS-1 not only has the catalytic oxidation effect of titanium, but also has the shape-selective effect and excellent stability...

AI Technical Summary

Problems solved by technology

Appl.Catal.A: Gen., 2001, 213: 163-171 reported the research of epoxidized propylene to generate propylene oxide (PO), H 2 and O 2 React in situ to generate H on the active sites of noble metals such as Pd 2 o 2 intermediate, then generated H 2 o 2 Intermediates in adjacent Ti 4+ Epoxidized propylene on the position to generate propylene oxide. Although the reaction conditions are mild and the selectivity is good, there are defects such as low catalyst activity and poor catalyst stability.