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La termometría in situ revela el comportamiento de fragmentación basado en la temperatura local en los catalizadores
Joren M Dorresteijn1, Bas Terlingen1, Koen W Bossers1
1Inorganic Chemistry and Catalysis Group, Debye Institute of Nanomaterials Science and Institute for Circular and Sustainable Chemistry, Utrecht University, Utrecht 3584, CG, The Netherlands.
Journal of the American Chemical Society
|February 10, 2025
Resumen
Este estudio revela cómo los catalizadores heterogéneos se fragmentan durante la polimerización de las olefinas, vinculando los cambios de temperatura a la evolución estructural. La termometría de luminiscencia monitoreó con precisión la fragmentación del catalizador y las fluctuaciones de temperatura durante la polimerización del etileno.
Área de la Ciencia:
- Catálisis
- Ciencias de los Polímeros
- Ciencias de los materiales
Sus antecedentes:
- La polimerización industrial de olefinas se basa en catalizadores heterogéneos que se fragmentan durante la reacción.
- La fragmentación del catalizador expone los sitios activos, lo que influye en la cinética de la polimerización y las propiedades del producto.
- La comprensión de los mecanismos de fragmentación y su relación con la temperatura es crucial para la optimización del proceso.
Objetivo del estudio:
- Investigar el comportamiento de fragmentación de catalizadores heterogéneos durante la polimerización de olefinas.
- Para correlacionar las fluctuaciones de temperatura con los cambios estructurales del catalizador y la cinética de polimerización.
- Demostrar un nuevo método para sondear las temperaturas de las partículas del catalizador in situ.
Principales métodos:
- Se utilizó un sistema de catalizador de modelo de metalloceno con LaOCl dopado con Nd.
- Se utiliza la termometría de luminiscencia para controlar los cambios de temperatura en las partículas del catalizador.
- Modelos de fragmentación del catalizador observados y analizados durante la polimerización del etileno en fase gaseosa.
Principales resultados:
- Se observó un aumento de la temperatura de +43 °C durante la polimerización del etileno, lo que confirma la exotermia de la reacción.
- Detalló la ruptura de capa por capa y la fragmentación biseccional del núcleo del catalizador.
- Probó con éxito las temperaturas individuales de las partículas del catalizador, correlacionándolas con la evolución estructural.
Conclusiones:
- La termometría de luminiscencia proporciona una herramienta poderosa para el estudio de la catálisis heterogénea.
- La fragmentación del catalizador es un proceso dependiente de la temperatura que influye en la polimerización.
- La metodología desarrollada puede aplicarse a diversos sistemas catalíticos heterogéneos para un análisis en profundidad.
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