Oxidación de glucosa y furfural sobre catalizadores de vo/cnt funcionalizados.
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Date
2024
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Universidad de Concepción
Abstract
En esta tesis fueron estudiados catalizadores de vanadio soportados en nanotubos de carbono en la reacción de conversión de glucosa en agua y oxidación de furfural en medio líquido y gaseoso. Se analizó el efecto de la funcionalización del nanotubo VO/CNT, VO/CNT-COOH y VO/CNT-NH2. Para mejorar el anclaje del vanadio, los catalizadores fueron sometidos a un proceso de dispersión ultrasónica. Los sólidos fueron caracterizados mediante análisis químico, TGA-DTG, DRX, isotermas de adsorción de N2, SEM, TEM, Raman, DTP-NH3 y XPS. La conversión catalítica de la glucosa en agua a 140°C y oxidación parcial del furfural en medio orgánico a 150°C se evaluó en un reactor batch y la reacción de oxidación parcial de furfural en fase gas en un reactor de flujo continuo entre 305 y 350°C. Se encontró que en reactor batch la lixiviación del vanadio, superior al 50% es responsable de la pérdida de actividad posterior al primer ciclo de reacción. En flujo continuo, la actividad se mantuvo en ciclos de reacción y para el catalizador VO/CNT-NH2 se alcanzó una conversión del 90% y una selectividad hacia anhídrido maleico del 40% a 320°C. Los reciclos mantuvieron la actividad catalítica con cambios en el rendimiento de la reacción hacia productos de oxidación parcial y total, CO y CO2.
In this thesis, vanadium catalysts supported on carbon nanotubes were studied to be used in the reaction of glucose conversion in water and oxidation of furfural in liquid and gaseous medium. The effect of functionalization of the VO/CNT, VO/CNT-COOH and VO/CNT-NH2 nanotube was studied. To improve the anchoring of vanadium, the catalysts were subjected to an ultrasonic dispersion process. The solids were characterized by chemical analysis, TGA-DTG, XRD, N2 adsorption isotherms, SEM, TEM, Raman, DTP-NH3 and XPS. Glucose catalytic conversion into water at 140°C and partial oxidation of furfural in an organic medium at 150°C was evaluated in a batch reactor and the partial oxidation reaction of furfural in the gas phase in a flow reactor between 305 and 350°C. It was found that in batch reactors, vanadium leaching of more than 50% is responsible for the loss of activity after the first reaction cycle. In a flow reactor, the activity is maintained in reaction cycles and for the VO/CNT-NH2 catalyst a conversion of 90% and selectivity towards maleic anhydride of 40% is achieved at 320°C. The recycles maintain the catalytic activity with changes in the yield of the reaction towards partial and total oxidation products (COx).
In this thesis, vanadium catalysts supported on carbon nanotubes were studied to be used in the reaction of glucose conversion in water and oxidation of furfural in liquid and gaseous medium. The effect of functionalization of the VO/CNT, VO/CNT-COOH and VO/CNT-NH2 nanotube was studied. To improve the anchoring of vanadium, the catalysts were subjected to an ultrasonic dispersion process. The solids were characterized by chemical analysis, TGA-DTG, XRD, N2 adsorption isotherms, SEM, TEM, Raman, DTP-NH3 and XPS. Glucose catalytic conversion into water at 140°C and partial oxidation of furfural in an organic medium at 150°C was evaluated in a batch reactor and the partial oxidation reaction of furfural in the gas phase in a flow reactor between 305 and 350°C. It was found that in batch reactors, vanadium leaching of more than 50% is responsible for the loss of activity after the first reaction cycle. In a flow reactor, the activity is maintained in reaction cycles and for the VO/CNT-NH2 catalyst a conversion of 90% and selectivity towards maleic anhydride of 40% is achieved at 320°C. The recycles maintain the catalytic activity with changes in the yield of the reaction towards partial and total oxidation products (COx).
Description
Tesis presentada para optar al grado de Doctor en Ciencias con mención en Química