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Un catalizador de níquel heterogéneo para la hidrogenólisis de éteres de arilo sin hidrogenación de areno
Alexey G Sergeev1, Jonathan D Webb, John F Hartwig
1Department of Chemistry, University of California, Berkeley, Berkeley, California 94720-1460, United States.
Journal of the American Chemical Society
|November 21, 2012
Resumen
Un nuevo catalizador de níquel heterogéneo divide eficientemente los éteres de arilo en arenas y alcoholes. Este catalizador funciona bajo condiciones suaves, ofreciendo una vía selectiva para la conversión de compuestos del modelo de lignina sin hidrogenación del anillo aromático.
Área de la Ciencia:
- La catálisis de la catálisis.
- Química organometálica Química orgánica de los metales.
- Química verde es la química verde.
Sus antecedentes:
- Los éteres de arilo, prevalentes en la lignina, plantean desafíos para la valorización de la biomasa.
- La escisión selectiva de los enlaces de éter arilico es crucial para la conversión de la lignina en sustancias químicas valiosas.
- Los métodos existentes a menudo requieren condiciones duras o carecen de selectividad.
Objetivo del estudio:
- Desarrollar un nuevo catalizador de níquel heterogéneo para la hidrogenólisis selectiva del éter de arilo.
- Para investigar el rendimiento del catalizador en condiciones suaves (baja presión y temperatura).
- Para comparar la selectividad del catalizador heterogéneo con sistemas homogéneos reportados anteriormente.
Principales métodos:
- Generación in situ de un catalizador de níquel heterogéneo a partir de precursores solubles (Ni ((COD) ((2) o Ni ((CH2TMS) 2 ((TMEDA)) con un aditivo de base ((t) BuONa).
- Prueba de la actividad y la selectividad del catalizador en la hidrogenólisis de compuestos modelo de éter arílico.
- Evaluar el rendimiento del catalizador a bajas cargas (0,25 mol %) y baja presión de hidrógeno (1 bar).
Principales resultados:
- El catalizador de níquel heterogéneo divide selectivamente los enlaces C ((Ar) -O en éteres de arilo para producir arenos y alcoholes.
- La reacción procede sin hidrogenación de los anillos aromáticos.
- El catalizador demuestra una alta eficiencia a bajas cargas (0,25 mol %) y 1 bar de presión de H2.
- El catalizador exhibe una selectividad distinta en comparación con los catalizadores de níquel homogéneos reportados anteriormente.
Conclusiones:
- Se ha desarrollado con éxito un catalizador de níquel heterogéneo robusto y selectivo para la hidrogenólisis del éter arílico.
- Este catalizador ofrece una ruta prometedora para la valorización de compuestos derivados de la lignina en condiciones suaves y sostenibles.
- Las diferencias observadas en la selectividad resaltan la naturaleza distinta de los sistemas catalíticos heterogéneos y homogéneos.
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