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Local order in depolymerized silicate lattices.
Graciela Pacheco-Malagón1, Patricia Pérez-Romo, Norma A Sanchez-Flores
1Centro de Ciencias Aplicadas y Desarrollo Tecnológico, Cd. Universitaria AP 70-186, C.P. 04510 México, DF.
Inorganic Chemistry
|November 8, 2005
Summary
Mesoporous silicates and zeolites depolymerize in glycerol at 200°C, forming amorphous gels. This process transforms silicon-oxygen-silicon bonds into silicon-oxygen-carbon bonds, preserving some structural order.
Area of Science:
- Materials Science
- Chemistry
- Nanotechnology
Background:
- Silicate networks in mesoporous materials and zeolites are crucial for their properties.
- Understanding the stability and transformation of these networks under extreme conditions is important.
Purpose of the Study:
- To investigate the depolymerization of silicate networks in mesoporous silicates and zeolites.
- To characterize the resulting amorphous gels and their structural properties.
Main Methods:
- Heating mesoporous silicates and zeolites in glycerol at approximately 200°C.
- Analyzing the transformation of Si-O-Si bonds to Si-O-C bonds.
- Characterizing the structural ordering of the resulting amorphous gels.
Main Results:
- Deep depolymerization of silicate networks occurred near 200°C in glycerol.
- Amorphous gels were formed within hours, with bond transformation to Si-O-C.
- Constitutional aluminum remained bound to the silica network.
- Short-range ordering was maintained, with structural units in the nanometer range (nm3).
Conclusions:
- Glycerol at high temperatures effectively depolymerizes silicate networks of mesoporous materials and zeolites.
- The process yields amorphous gels with preserved aluminum and some structural integrity.
- This transformation offers potential for novel material synthesis or modification.