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Conversión directa de bioetanol a isobuteno en óxidos mezclados nanométricos Zn{x}Zr{y}O{z} con sitios ácido-base
Junming Sun1, Kake Zhu, Feng Gao
1Institute for Interfacial Catalysis, Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
Journal of the American Chemical Society
|June 21, 2011
Resumen
Los óxidos mezclados de zinc-zirconio nanométricos permiten la conversión de alto rendimiento del bioetanol en isobuteno. Este nuevo catalizador suprime las reacciones no deseadas, logrando una selectividad de ~83% a través de una química de superficie a medida.
Área de la Ciencia:
- La catálisis de la catálisis.
- Ciencia de los materiales Ciencia de los materiales.
- Ingeniería Química Ingeniería Química.
Sus antecedentes:
- La conversión del bioetanol en isobuteno es un objetivo clave para la producción sostenible de combustibles.
- Los catalizadores de circonio a menudo sufren de una fuerte acidez, lo que lleva a reacciones secundarias no deseadas y coqueo.
- El desarrollo de catalizadores que controlen selectivamente las propiedades ácido-base es crucial para la mejora eficiente del bioetanol.
Objetivo del estudio:
- Para diseñar y sintetizar óxidos mezclados nanométricos Zn(x) Zr(y) O(z).
- Para lograr la conversión directa y de alto rendimiento del bioetanol en isobuteno.
- Para aclarar el mecanismo catalítico responsable de la alta selectividad.
Principales métodos:
- Síntesis de catalizadores de óxido mezclados de tamaño nanométrico Zn(x) Zr(y) O(z).
- Caracterización de las propiedades superficiales del catalizador (sitios ácidos y básicos).
- Prueba del rendimiento catalítico en la conversión directa de bioetanol en isobuteno.
Principales resultados:
- Se logró un alto rendimiento (~83%) de isobuteno a partir de bioetanol.
- Se ha demostrado la pasivación selectiva de los sitios ácidos fuertes de Lewis y el debilitamiento de los sitios ácidos de Brønsted en la zirconia por adición de ZnO.
- Reacciones no deseadas suprimidas como la deshidratación con bioetanol y la polimerización/cocción con acetona.
- Se identificó una vía de reacción dominante que involucra la deshidrogenación del etanol, la condensación de aldol y la conversión de acetona a isobuteno.
Conclusiones:
- Los óxidos mezclados nanométricos de Zn{x}Zr{y}O{z} son catalizadores efectivos para la conversión directa del bioetanol en isobuteno.
- Adaptar las propiedades ácido-base del catalizador es clave para lograr una alta selectividad y rendimiento.
- El catalizador desarrollado ofrece una ruta prometedora para la producción sostenible de isobuteno a partir de etanol derivado de la biomasa.
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