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Hidrogenación catalítica de un nitruro de manganeso en amoníaco

Sangmin Kim¹, Hongyu Zhong¹, Yoonsu Park¹

¹Department of Chemistry, Frick Laboratory, Princeton University, Princeton, New Jersey 08544, United States.

Journal of the American Chemical Society

|April 28, 2020

Resumen

Este estudio detalla un nuevo catalizador de hidruro de rodio para la hidrogenación de nitruro metálico, que produce amoníaco de manera eficiente. El ligando fenilimina mejora la estabilidad y actividad del catalizador, permitiendo la síntesis de amoníaco a través de la transferencia de electrones acoplados a protones.

Área de la Ciencia:

Química organometálica
Catálisis
Química inorgánica

Sus antecedentes:

La síntesis de amoníaco es crucial para la agricultura y la industria.
El desarrollo de catalizadores eficientes para la producción de amoníaco sigue siendo un desafío importante.
Los nitritos metálicos ofrecen una fuente alternativa de nitrógeno para la síntesis de amoníaco.

Objetivo del estudio:

Describir un nuevo catalizador de hidruro de rodio para la hidrogenación catalítica de nitritos metálicos para producir amoníaco.
Investigar el papel de la sustitución de ligandos en la estabilidad y actividad del catalizador.
Para aclarar el mecanismo de síntesis de amoníaco a través de la transferencia de electrones acoplados a protones.

Principales métodos:

Síntesis y caracterización de complejos de hidruro de rodio con los ligandos de fenilimina y fenilpiridina.
Cálculos de la Teoría Funcional de Densidad (DFT) para determinar las energías libres de disociación del enlace Rh-H.
Experimentos de hidrogenación catalítica con un precursor de nitruro de manganeso bajo condiciones de disolvente variables.
Análisis espectroscópico para identificar los productos intermedios de la reacción.

Principales resultados:

El complejo de rodio sustituido por fenilimina exhibió una mayor estabilidad térmica que el análogo de fenilpiridina.
Los cálculos de DFT mostraron energías libres de disociación Rh-H comparables para ambos complejos.
El precatalizador de fenilimina rodio hidrogenó con éxito un nitruro de manganeso para producir amoníaco con hasta 6 volúmenes de producción.
La síntesis de amoníaco fue habilitada por la transferencia de electrones acoplados a protones en disolventes no polares, suprimiendo las reacciones secundarias no deseadas.

Conclusiones:

Los complejos de rodio sustituidos por fenilimina son catalizadores eficaces para la síntesis de amoníaco a partir de nitritos metálicos.
La estabilidad y la actividad del catalizador están influenciadas por la elección del ligando y la polaridad del disolvente.
La transferencia de electrones acoplados a protones es un mecanismo viable para la producción catalítica de amoníaco.

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