Catalizadores en base a metales nobles soportados en nanotubos de haloisita para hidrogenación de nitroarenos y valorización de furfural.
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Date
2025
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Universidad de Concepción
Abstract
Esta tesis reporta la preparación de catalizadores en base a nanotubos de haloisita (HNT) órgano-modificados en el lumen donde se depositaron nanopartículas (NPs) de Pd y Au (%=0.0; 0.10; 0.25; 0.50) empleando un método asistido por amino-silano. Las NPs metálicas se inmovilizaron de forma uniforme dentro del lumen del soporte. Un aumento en la carga de metal (0.10 a 0.50% en masa) muestra para los catalizadores de Pd una distribución de 1.5–2.2 nm y para los de Au se encuentran NPs de 1.5–6.5 nm. Los catalizadores se evaluaron en la hidrogenación de furfural (FUR) y de nitrobenceno (NB), en condiciones de reacción optimizadas, los resultados muestran que los catalizadores Pd son sensibles a la distribución de tamaño de las NPs mientras que Los catalizadores de Au no muestran esta dependencia. El catalizador 0.50% Pd alcanza el máximo de conversión y selectividad para producir alcohol tetrahidrofurfurílico (THFOH) y anilina (AN), con una reciclabilidad moderada, desactivándose en el décimo ciclo en la hidrogenación de FUR y en el quinto ciclo en la hidrogenación de NB. El catalizador al 0.10% Au exhibe una destacada estabilidad y reciclabilidad, conservando su actividad catalítica en 10 ciclos consecutivos para ambas reacciones de hidrogenación. El método propuesto ofrece una ruta innovadora para sintetizar catalizadores de metales soportados en HNT órgano-modificada que sean eficientes y reciclables para su potencial uso en reacciones de hidrogenación catalítica.
Pd- and Au-loaded organo-modified halloysite nanotube (HNT) lumens were synthesized via an amine-silane-assisted method. The Pd and Au nanoparticles (NPs) were uniformly distributed within the HNT lumens. An increase in metal loading (from 0.10 to 0.50 wt%) resulted in similar metal NP distribution for the Pd-based catalyst while a broader metal NP size distribution for the Au-based catalysts was detected. The catalysts were evaluated for both furfural (FUR) and nitrobenzene (NB) hydrogenation under optimized reaction conditions to assess their performance and reusability. Results indicate that the Pd-based catalysts are sensitive to the variations of metal NP size (1.5–2.2 nm) whereas Au-based catalysts are no-sensitive to variations in the metal NP size (1.5–6.5 nm). The 0.50Pd wt% demonstrated superior catalytic performance for both substrates exceeding 98% selectivity to produce tetrahydrofurfuryl alcohol (THFOH) and aniline (AN), respectively. However, the recyclability studies displayed that the catalyst was deactivated at the 10 catalytic cycles during the hydrogenation of FUR, whereas, in the hydrogenation of NB, 5 catalytic cycles were achieved with maximum conversion and selectivity. For the Au-based catalyst, 0.10 wt% Au exhibited exceptional stability and recyclability, retaining its catalytic activity with minimal loss over at least 10 consecutive reuse cycles for both hydrogenation reactions. The proposed method offers an innovative route for synthesizing efficient and reusable metal-loaded organo-modified HNT catalysts for use in hydrogenation reactions and demonstrates significant potential.
Pd- and Au-loaded organo-modified halloysite nanotube (HNT) lumens were synthesized via an amine-silane-assisted method. The Pd and Au nanoparticles (NPs) were uniformly distributed within the HNT lumens. An increase in metal loading (from 0.10 to 0.50 wt%) resulted in similar metal NP distribution for the Pd-based catalyst while a broader metal NP size distribution for the Au-based catalysts was detected. The catalysts were evaluated for both furfural (FUR) and nitrobenzene (NB) hydrogenation under optimized reaction conditions to assess their performance and reusability. Results indicate that the Pd-based catalysts are sensitive to the variations of metal NP size (1.5–2.2 nm) whereas Au-based catalysts are no-sensitive to variations in the metal NP size (1.5–6.5 nm). The 0.50Pd wt% demonstrated superior catalytic performance for both substrates exceeding 98% selectivity to produce tetrahydrofurfuryl alcohol (THFOH) and aniline (AN), respectively. However, the recyclability studies displayed that the catalyst was deactivated at the 10 catalytic cycles during the hydrogenation of FUR, whereas, in the hydrogenation of NB, 5 catalytic cycles were achieved with maximum conversion and selectivity. For the Au-based catalyst, 0.10 wt% Au exhibited exceptional stability and recyclability, retaining its catalytic activity with minimal loss over at least 10 consecutive reuse cycles for both hydrogenation reactions. The proposed method offers an innovative route for synthesizing efficient and reusable metal-loaded organo-modified HNT catalysts for use in hydrogenation reactions and demonstrates significant potential.
Description
Tesis presentada para optar al grado de Doctor/a en Ciencias con mención en Química.
Keywords
Catalizadores, Nanopartículas, Hidrogenación, Reciclaje