Exploración del potencial catalítico de metal-organic frameworks con sitios de coordinación insaturados en síntesis orgánica.
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Date
2024
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Universidad de Concepción
Abstract
En los últimos años, los Metal-Organic Frameworks (MOFs) han ganado relevancia en diversas aplicaciones, destacándose en la catálisis heterogénea debido a sus propiedades únicas, como una alta porosidad y superficie específica, estabilidad térmica, y la capacidad de incorporar centros catalíticamente activos.
En este trabajo se realizó la síntesis, caracterización y evaluación catalítica de cuatro MOFs: HKUST-1, MIL-101(Cr), UiO-66-NH2, y MIL-53(Al). Destaca la síntesis de MIL-53(Al) mediante reciclaje ascendente (up-cycling) a partir de latas de aluminio y botellas de PET, lo que promueve la economía circular al demostrar la viabilidad de producir MOFs a partir de residuos. Los MOFs fueron evaluados como catalizadores heterogéneos en dos reacciones de formación de enlaces C-N. Se reporta por primera vez el uso de MOFs como catalizadores en la síntesis de hidracidas a partir de aldehídos y azocompuestos. La reacción se llevó a cabo a 60 °C durante 48 horas en acetato de etilo, obteniéndose 16 compuestos con rendimientos entre 54 % y 97 %. También se estudió la síntesis de pirroles mediante la reacción de Paal-Knorr a partir de anilinas y acetonilacetona. La reacción se llevó a cabo en condiciones libres de solventes utilizando irradiación de microondas durante 5 minutos, produciendo 7 pirroles con rendimientos entre 50 % y 96 %. En ambas reacciones, MIL-53(Al) demostró ser el catalizador más eficiente, con un contenido MOF de 10 mol % y 5 mol %, respectivamente. Además, se evaluó la estabilidad y reutilización de MIL-53(Al) durante cuatro ciclos catalíticos consecutivos, manteniendo su rendimiento con una disminución mínima.
La combinación de alta actividad catalítica, estabilidad y origen sostenible del MIL-53(Al) representa un avance significativo en la catálisis heterogénea y la química verde. La aplicación pionera de MOFs en la síntesis de hidracidas amplía las fronteras de la catálisis con estos materiales, proporcionando un ejemplo claro de cómo los principios de la economía circular y la innovación en catálisis pueden aplicarse en la síntesis de materiales avanzados y en el desarrollo de procesos químicos más eficientes y ambientalmente amigables.
In recent years, Metal-Organic Frameworks (MOFs) have gained relevance in various applications, they stand out in heterogeneous catalysis due to their unique properties, such as high porosity and specific surface area, thermal stability, and the ability to incorporate catalytically active centers. In this work, the synthesis, characterization, and catalytic evaluation of four MOFs were carried out: HKUST-1, MIL-101(Cr), UiO-66-NH2, and MIL-53(Al). The synthesis of MIL-53(Al) through up-cycling from aluminum cans and PET bottles is particularly notable, promoting the circular economy by demonstrating the feasibility of producing MOFs from waste materials. MOFs were evaluated as heterogeneous catalysts in two C-N bond-forming reactions. For the first time, MOFs were reported as catalysts in the synthesis of acylhydrazides from aldehydes and azocompounds. The reaction was carried out at 60 °C for 48 hours in ethyl acetate, obtaining 16 compounds with yields ranging from 54 % to 97 %. The synthesis of pyrroles via the Paal-Knorr reaction from anilines and acetylacetone was also studied. The reaction was conducted under solvent-free conditions using microwave irradiation for 5 minutes, producing 7 pyrroles with yields between 50 % and 96 %. In both reactions, MIL-53(Al) proved to be the most efficient catalyst, with catalyst loads of 10 mol% and 5 mol %, respectively. Additionally, the stability and reusability of MIL-53(Al) were evaluated over four consecutive catalytic cycles, maintaining its performance with minimal decline. The combination of high catalytic activity, stability, and sustainable origin of MIL-53(Al) represents a significant advancement in heterogeneous catalysis and green chemistry. The pioneering application of MOFs in the synthesis of hydrazides expands the frontiers of catalysis with these materials, providing a clear example of how the principles of the circular economy and catalysis innovation can be applied in the synthesis of advanced materials and the development of more efficient and environmentally friendly chemical processes.
In recent years, Metal-Organic Frameworks (MOFs) have gained relevance in various applications, they stand out in heterogeneous catalysis due to their unique properties, such as high porosity and specific surface area, thermal stability, and the ability to incorporate catalytically active centers. In this work, the synthesis, characterization, and catalytic evaluation of four MOFs were carried out: HKUST-1, MIL-101(Cr), UiO-66-NH2, and MIL-53(Al). The synthesis of MIL-53(Al) through up-cycling from aluminum cans and PET bottles is particularly notable, promoting the circular economy by demonstrating the feasibility of producing MOFs from waste materials. MOFs were evaluated as heterogeneous catalysts in two C-N bond-forming reactions. For the first time, MOFs were reported as catalysts in the synthesis of acylhydrazides from aldehydes and azocompounds. The reaction was carried out at 60 °C for 48 hours in ethyl acetate, obtaining 16 compounds with yields ranging from 54 % to 97 %. The synthesis of pyrroles via the Paal-Knorr reaction from anilines and acetylacetone was also studied. The reaction was conducted under solvent-free conditions using microwave irradiation for 5 minutes, producing 7 pyrroles with yields between 50 % and 96 %. In both reactions, MIL-53(Al) proved to be the most efficient catalyst, with catalyst loads of 10 mol% and 5 mol %, respectively. Additionally, the stability and reusability of MIL-53(Al) were evaluated over four consecutive catalytic cycles, maintaining its performance with minimal decline. The combination of high catalytic activity, stability, and sustainable origin of MIL-53(Al) represents a significant advancement in heterogeneous catalysis and green chemistry. The pioneering application of MOFs in the synthesis of hydrazides expands the frontiers of catalysis with these materials, providing a clear example of how the principles of the circular economy and catalysis innovation can be applied in the synthesis of advanced materials and the development of more efficient and environmentally friendly chemical processes.
Description
Tesis presentada para optar al grado de Doctor en Ciencias con mención en Química
Keywords
Catálisis, Metal-organic frameworks, Compuestos orgánicos Síntesis