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Authors
Abstract(s)
Este trabalho teve como objetivo a produção de nanopartículas metálicas de prata e cobre suportadas em materiais de carbono provenientes de desperdícios da biomassa (borras de café) e a sua aplicação em reações catalíticas de oxidação ecossustentáveis de interesse industrial, o 1-feniletanol, álcool benzílico e tolueno e de redução de interesse industrial, o 4-nitrofenol.
Neste trabalho foram sintetizados dois compósitos de cobre/carbono com diferentes teores de metal (23 e 36% m/m) e dois compósitos de prata/carbono (9 e 16% m/m). O material de carbono é proveniente das borras de café tendo sido usado na preparação de vários compósitos. Os compósitos foram caracterizados por SEM e TEM, FT-IR ATR e ICP.
Para a oxidação peroxidativa dos álcoois foram estudados diferentes parâmetros, nomeadamente o tipo e quantidade de catalisador, a quantidade de oxidante (TBHP, aq. 70%), a temperatura e o tempo de reação. Na reação de oxidação peroxidativa do tolueno foi estudado o tipo (H2O2 a 30% e TBHP a 70%) e a quantidade de oxidante, a temperatura e o tempo de reação.
Para a oxidação do álcool secundário, 1-feniletanol, o rendimento máximo, em 2 h, foi de 91,5%. Na oxidação peroxidativa do álcool primário, álcool benzílico, o rendimento máximo total, em 2 h, foi de 65,7% com uma seletividade em benzaldeído de 8,3%. Foram ainda estudados derivados do álcool benzílico nas melhores condições reacionais. Por último, na oxidação do tolueno, o rendimento máximo total foi de 55,6% com uma seletividade em benzaldeído de 10,8%.
Para a redução do 4-nitrofenol os parâmetros estudados foram a ordem de adição dos reagentes, o tipo e quantidade de catalisador, a concentração do substrato e a temperatura. O valor de conversão mais elevado e de constante de velocidade foram de 75,8% e 0,521 min-1, respetivamente.
This work aims to produce metallic silver and copper nanoparticles supported on carbon materials derived from biomass waste and their application in catalytic reactions of eco-sustainable oxidation of industrial interest, namely 1-phenylethanol, benzyl alcohol and toluene and reduction of industrial interest, 4-nitrophenol. In this work, two copper/carbon composites with different metal contents (23 and 36% m/m) and two silver/carbon composites (9 and 16% m/m) were synthesized. The carbon material derived from coffee grounds, and several composites were prepared using carbon as support. The composites were characterized by SEM and TEM, FT-IR ATR and ICP. For the peroxidative oxidation of alcohols, different parameters were studied, namely the type and amount of catalyst, the amount of oxidant (TBHP, aq. 70%), the temperature and the reaction time. For the peroxidative oxidation of toluene, the type (30% aq. H2O2 and 70% aq. TBHP) and the amount of oxidant, the temperature and the reaction time were studied. For the oxidation of the secondary alcohol, 1-phenylethanol, the maximum yield, in 2 h, was 91.5%. In the peroxidative oxidation of the primary alcohol, benzyl alcohol, the maximum total yield, in 2 h, was 65.7% with a selectivity on benzaldehyde of 8.3% and these reaction conditions served to study the effect of the substituents of this alcohol. Finally, in the oxidation of toluene, the maximum total yield was 55.6% whose selectivity in benzaldehyde was 10.8%. For the reduction of 4-nitrophenol the parameters studied were the order of addition of the reactants, the type and amount of catalyst, the concentration of the substrate and the temperature. The highest conversion value and rate constant were 75.8% and 0.521 min-1, respectively.
This work aims to produce metallic silver and copper nanoparticles supported on carbon materials derived from biomass waste and their application in catalytic reactions of eco-sustainable oxidation of industrial interest, namely 1-phenylethanol, benzyl alcohol and toluene and reduction of industrial interest, 4-nitrophenol. In this work, two copper/carbon composites with different metal contents (23 and 36% m/m) and two silver/carbon composites (9 and 16% m/m) were synthesized. The carbon material derived from coffee grounds, and several composites were prepared using carbon as support. The composites were characterized by SEM and TEM, FT-IR ATR and ICP. For the peroxidative oxidation of alcohols, different parameters were studied, namely the type and amount of catalyst, the amount of oxidant (TBHP, aq. 70%), the temperature and the reaction time. For the peroxidative oxidation of toluene, the type (30% aq. H2O2 and 70% aq. TBHP) and the amount of oxidant, the temperature and the reaction time were studied. For the oxidation of the secondary alcohol, 1-phenylethanol, the maximum yield, in 2 h, was 91.5%. In the peroxidative oxidation of the primary alcohol, benzyl alcohol, the maximum total yield, in 2 h, was 65.7% with a selectivity on benzaldehyde of 8.3% and these reaction conditions served to study the effect of the substituents of this alcohol. Finally, in the oxidation of toluene, the maximum total yield was 55.6% whose selectivity in benzaldehyde was 10.8%. For the reduction of 4-nitrophenol the parameters studied were the order of addition of the reactants, the type and amount of catalyst, the concentration of the substrate and the temperature. The highest conversion value and rate constant were 75.8% and 0.521 min-1, respectively.
Description
Trabalho Final de Mestrado para a obtenção do Grau de Mestre em Engenharia Química e Biológica
Keywords
Nanopartículas Cobre Prata Borras de café Carbono Oxidação 1-feniletanol Álcool benzílico Tolueno Redução 4-nitrofenol Nanoparticles Copper Silver Coffee grounds Carbon Oxidation 1-phenylethanol Benzyl alcohol Toluene Reduction 4-nitrophenol
Citation
DIAS, Ana Sofia Melo Lopes – Produção de nanopartículas metálicas e o seu suporte em carbono para aplicações catalíticas. Lisboa: Instituto Superior de Engenharia de Lisboa, 2021. Dissertação de Mestrado.
Publisher
Instituto Superior de Engenharia de Lisboa