Mono- and bifunctional MFI, BEA and MCM-41 titanium-molecular sieves. Part 1. Synthesis and characterization

✍ Scribed by D Trong On; S.V Nguyen; V Hulea; E Dumitriu; S Kaliaguine

• Publisher: Elsevier Science
• Year: 2003
• Tongue: English
• Weight: 218 KB
• Volume: 57
• Category: Article
• ISSN: 1387-1811
• DOI: 10.1016/s1387-1811(02)00564-4

✦ Synopsis

A series of mono-and bifunctional titanium-molecular sieves containing different trivalent ions, e.g. Al 3þ , B 3þ and Ga 3þ with MFI, BEA and MCM-41 topologies has been prepared and characterized. Various techniques including XRD, N 2 adsorption, UV-visible and MAS-NMR were used to monitor the physico-chemical properties of these materials. The results revealed that the Ti and the trivalent ions are mostly incorporated into catalyst framework. The acidic properties of these catalysts were studied by FTIR spectra in the OH as well as in the pyridine regions. These results revealed that no Br€ o onsted acid sites were present in TS-1, Ti-MCM-41 and B-Ti-MCM-41. The FTIR spectra in the pyridine regions at different temperatures indicate that the acidic strength is in the following order: TS-1 < B-TS-1 ( Ga-TS-1 6 Al-TS-1 and Ti-MCM-41 < B-Ti-MCM-41 ( Ga-Ti-MCM-41 < Al-Ti-MCM-41. This work illustrates how redox catalysts such as TS-1 and Ti-MCM-41 can be modified by introducing acid sites of controlled acid strength through lattice insertion of different trivalent cations.