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Synthesis and Reaction Chemistry of Nanosize Monosodium Titanate
Published on: February 23, 2016
Ti coordination in titanium silicalite-1.
Wallace O Parker1, Roberto Millini
1Physical Chemistry Department, EniTecnologie S.p.A., via Maritano 26, 20097 San Donato Milanese, Italy.
Journal of the American Chemical Society
|February 2, 2006
Summary
Incorporating titanium (TiIV) or boron (BIII) into silicalite-1 structures reduces siloxy groups. This confirms the negative charge of heteroatoms, forming TiO5 or BO4 sites within the MFI framework.
Area of Science:
- Materials Science
- Catalysis
- Inorganic Chemistry
Background:
- Silicalite-1 (MFI structure) is a crucial zeolite material.
- Understanding heteroatom incorporation is key for tailoring zeolite properties.
- The charge balance in substituted zeolites affects their catalytic activity.
Purpose of the Study:
- To investigate the effect of TiIV and BIII heteroatom incorporation on silicalite-1.
- To quantify changes in siloxy groups during heteroatom substitution.
- To determine the charge and coordination of incorporated heteroatoms.
Main Methods:
- Synthesis of silicalite-1 with progressive isomorphous incorporation of TiIV or BIII.
- 1H Magic Angle Spinning Nuclear Magnetic Resonance (MAS NMR) spectroscopy.
- Quantification of silanol protons H-bonded to siloxy oxygen.
Main Results:
- Isomorphous incorporation of TiIV or BIII decreased the amount of siloxy groups in silicalite-1.
- The decrease in siloxy groups is directly related to the amount of incorporated heteroatoms.
- 1H MAS NMR confirmed the negative charge on the incorporated heteroatoms.
Conclusions:
- The incorporated heteroatoms (TiIV, BIII) exist as negatively charged TiO5 or BO4 sites.
- This finding clarifies the charge compensation mechanism in heteroatom-substituted silicalite-1.
- The study provides insights into the structural and electronic properties of modified MFI zeolites.
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