Titanium silicalite molecular sieve and modification method and application thereof

Abstract

The invention discloses a titanium silicalite molecular sieve and a modification method and application thereof, and belongs to the technical field of petrochemical engineering, and the modification method comprises the following steps: 1, pretreating the titanium silicalite molecular sieve, then mixing the pretreated titanium silicalite molecular sieve with silane and alkali metal hydroxide, and then carrying out ball milling treatment to obtain the titanium silicalite molecular sieve subjected to ball milling treatment; 2, uniformly dispersing the ball-milled titanium silicalite molecular sieve in an alkali solution, and then performing reacting at the temperature of 80-160 DEG C for 3-18 hours to obtain a primarily modified titanium silicalite molecular sieve; 3, in an inert gas atmosphere, carrying out heat preservation on the primarily modified titanium silicalite molecular sieve at the temperature of 500-800 DEG C for 4-36 hours to complete modification of the titanium silicalite molecular sieve. The modification method provided by the invention is simple to operate, and the prepared titanium silicalite molecular sieve has strong hydrophobicity, titanium species are not easy to lose, the stability is good, and the catalytic performance in propylene and hydrogen peroxide gas phase epoxidation reaction is good.

Description

technical field [0001] The invention relates to the technical field of petrochemical industry, in particular to a titanium-silicon molecular sieve (TS-1) and its modification method and application. Background technique [0002] Titanium silicate molecular sieve is a kind of silicate zeolite containing titanium heteroatoms in the crystal framework. Among them, TS-1 is an extremely important member of the titanium-silicon molecular sieve family. Taramasso et al. first reported the preparation of TS-1 molecular sieve by hydrothermal synthesis in 1983. It has an MFI topology, and the TS-1 molecular sieve channel is formed by the intersection of zigzag ten-membered ring channels and straight ten-membered ring channels. Three-dimensional ten-membered ring channel system. [0003] Studies have shown that the isolated four-coordinated framework titanium in TS-1 molecular sieves is the active center for catalytic oxidation, and most of the framework titanium species are located in...

AI Technical Summary

Problems solved by technology

[0003] Studies have shown that the isolated four-coordinated framework titanium in TS-1 molecular sieves is the active center for catalytic oxidation, and most of the framework titanium species are located in the pores of molecular sieves. Therefore, the prior art usually uses TS-1 as a catalyst, H 2 o 2 A new process for oxidizing propylene epoxidation to PO (HPPO process), however, the TS-1 molecular sieve prepared by traditional methods such as the classical method has low hydrophobicity, easy loss of titanium species, and poor stability, resulting in poor performance in the HPPO process