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Bifuncionalidad homogénea-heterogénea en la síntesis de acetato de vinilo catalizado por Pd

Deiaa M Harraz¹, Kunal M Lodaya¹, Bryan Y Tang²

¹Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA.

Science (New York, N.Y.)

|April 3, 2025

Resumen

Este estudio revela que la síntesis de acetato de vinilo catalizado por paladio implica un ciclo dinámico en el que el paladio heterogéneo ((0)) y el paladio homogéneo ((II) se interconvierten. Esta conversión de fase es crucial para el proceso catalítico.

Área de la Ciencia:

Catálisis química
Ciencias de los materiales
La electroquímica

Sus antecedentes:

Los mecanismos de catálisis tradicionalmente asumen una sola fase activa (homogénea o heterogénea).
La síntesis de acetato de vinilo catalizado por paladio es un proceso industrial significativo.

Objetivo del estudio:

Para investigar el paradigma mecanicista de la síntesis de acetato de vinilo catalizado por paladio.
Esclarecer el papel de la interconversión de fase entre especies heterogéneas y homogéneas de paladio.

Principales métodos:

Utilizó sondas electroquímicas para controlar la actividad catalítica.
Se utiliza protección galvánica para inhibir la corrosión del paladio.
Analizó los cambios dinámicos de fase durante la catálisis.

Principales resultados:

Se ha demostrado que el paladio heterogéneo ((0)) y el paladio homogéneo ((II) se interconvierten durante la síntesis del acetato de vinilo.
Identificó el paladio heterogéneo como un electrocatalizador de reducción de oxígeno que genera el potencial para la formación de paladio.
Se ha demostrado que el paladio homogéneo ((II) cataliza la acetoxilación del etileno, regenerando el paladio heterogéneo ((0).
Se ha observado un envenenamiento catalítico reversible tras la inhibición de la corrosión del paladio (I) al paladio (II).

Conclusiones:

El ciclo catalítico se basa en la interconversión de fase dinámica entre el paladio ((0) y el paladio ((II).
Esta interconversión acopla la reactividad entre el material y los sitios activos moleculares.
Destaca una nueva perspectiva mecanicista para los procesos catalíticos que implican cambios de fase.

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