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La selectividad en función del tamaño de las nanopartículas en la hidrogenación catalítica de alcoholes insaturados
Somnath Bhattacharjee1, David M Dotzauer, Merlin L Bruening
1Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA.
Journal of the American Chemical Society
|February 24, 2009
Resumen
El tamaño de las nanopartículas del catalizador tiene un impacto dramático en la selectividad de hidrogenación. Las nanopartículas de paladio más pequeñas mejoran la selectividad de los alcoholes insaturados monosubstituidos, mientras que las más grandes favorecen los compuestos multisubstituidos.
Área de la Ciencia:
- Ciencia de los materiales Ciencia de los materiales.
- La catálisis de la catálisis.
- Nanotecnología La nanotecnología es la nanotecnología.
Sus antecedentes:
- El desarrollo de catalizadores eficientes y selectivos es crucial para la síntesis química.
- El control del tamaño de las nanopartículas es clave para ajustar las propiedades catalíticas.
Objetivo del estudio:
- Para sintetizar catalizadores de nanopartículas de paladio (Pd) incrustados en películas de polielectrolitos.
- Investigar el efecto del tamaño de las nanopartículas Pd en la selectividad catalítica de las reacciones de hidrogenación.
Principales métodos:
- Adsorción capa por capa de complejos de poli (ácido acrílico) -Pd (II) y poli (etilenimina) en alumina.
- Reducción de Pd(II) a nanopartículas Pd utilizando NaBH(4).
- Variando la proporción de ácido poliacrílico a PdII para controlar el tamaño de las nanopartículas (2.23.4 nm).
Principales resultados:
- La selectividad catalítica varió significativamente con el tamaño de las nanopartículas Pd.
- Las frecuencias de rotación (TOF) para los alcoholes insaturados monosubstituidos aumentaron con la disminución del tamaño de las nanopartículas.
- Los TOF para los alcoholes insaturados multisubstituidos mostraron una tendencia opuesta, aumentando con el mayor tamaño de las nanopartículas.
Conclusiones:
- Las nanopartículas Pd más pequeñas exhiben una mayor selectividad para hidrogenar alcoholes insaturados monosubstituidos.
- Las nanopartículas de Pd más grandes son más selectivas para los alcoholes insaturados multisubstituidos.
- La selectividad dependiente del tamaño de las nanopartículas se atribuye a la disponibilidad de sitios activos para la unión al sustrato.
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