Study On Synthesis, Modification And Catalytic Oxidation Performance To Olefins Of Titanium Silicalite Molecular Sieves

Titanium silicalite molecular sieves are a type of heteroelements-containing molecular sieves which are comprised of Ti-0 tetrahedrons and S:-0 tetrahedrons. Being a new type of catalytic materials with incorporation of Ti atoms into the pure silicalite molecular sieves framework, titanium silicalite molecular sieves have the higher thermal stability, anti-acidity, hydrophobicity and the outstanding ability to catalyze various oxidation reactions selectively, such as alcohol oxidation, alkane oxidation, alkene epoxidation, ammoximation of cyclohexanone, oxidation or hydroxylation of aromatic compounds, et al. Because the deep oxidation and contamination to environment can be avoided by using titanium silicalite molecular sieves, it attract much attention all over the world and have been reputed as the green catalysts. The unique catalytic performance of titanium silicalite mdecular sieve has laid the foundation for research of high selectively cataly(?)e oxidation of hydrocarbons and development of new environmentally friendly oxidation technology. The invention of titanium silicalite molecular sieves has been considered as the milestone of the zeolite catalysis area during the last decade. The influences of different synthetic methods and conditions on the structures and features of TS-1,TS-2, Ti-MCM-41, Ti-HMS, Ti-MSU, Ti-AA have been investigated by characterization of XRD, FT-IR, UV-Vis, SEM, EDS, TG et al. in this paper. The influences of modifying methods on the catalytic performances of (?)anium silicalite molecular sieves have been valued through oxidation of alkenes.TS-1 with MFI topology has been synthesized using tetraethyl orthosilicate (TEOS) and amorphous silica as Si sources. The influencing factors of the particles size and crystallization kinetic, the influence of modifying method on the catalytic property and the regeneration of TS-1 have been investigated. The influence of the particle size of TS-1 on its catalytic activity has been attributed to (?)orrelation of the catalyst surface efficiency with the particle size of TS-1. The crystallization kinetics are different for synthesis of TS-1 using different Si sources. When amorphous silica...