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Synthesis and Reaction Chemistry of Nanosize Monosodium Titanate
Published on: February 23, 2016
La coordinación de Ti en la silicalita-1 de titanio es
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
Resumen
La incorporación de titanio (TiIV) o boro (BIII) en las estructuras de silicalita-1 reduce los grupos siloxi. Esto confirma la carga negativa de los heteroátomos, formando sitios de TiO5 o BO4 dentro del marco de las IFM.
Área de la Ciencia:
- Ciencia de los materiales Ciencia de los materiales.
- La catálisis de la catálisis.
- Química Inorgánica La Química Inorgánica es la química inorgánica.
Sus antecedentes:
- La silicalita-1 (estructura MFI) es un material esencial de la zeolita.
- Comprender la incorporación de heteroátomos es clave para adaptar las propiedades de la zeolita.
- El balance de carga en las zeolitas sustituidas afecta a su actividad catalítica.
Objetivo del estudio:
- Investigar el efecto de la incorporación de los heteroátomos TiIV y BIII en la silicalita-1.
- Para cuantificar los cambios en los grupos siloxi durante la sustitución heteroatómica.
- Para determinar la carga y la coordinación de los heteroátomos incorporados.
Principales métodos:
- Síntesis de silicalita-1 con la incorporación progresiva isomorfa de TiIV o BIII.
- Espectroscopia de resonancia magnética nuclear (MAS NMR) giratoria de ángulo mágico de 1H.
- Cuantificación de los protones de silanol H-unidos al oxígeno siloxi.
Principales resultados:
- La incorporación isomórfica de TiIV o BIII disminuyó la cantidad de grupos siloxi en la silicalita-1.
- La disminución de los grupos siloxi está directamente relacionada con la cantidad de heteroátomos incorporados.
- 1H MAS RMN confirmó la carga negativa en los heteroátomos incorporados.
Conclusiones:
- Los heteroátomos incorporados (TiIV, BIII) existen como sitios TiO5 o BO4 cargados negativamente.
- Este hallazgo aclara el mecanismo de compensación de carga en la silicalita-1.1, sustituida por heteroátomos.
- El estudio proporciona información sobre las propiedades estructurales y electrónicas de las zeolitas modificadas de las IFM.
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