Membranas de celulose não-modificada contendo nanopartículas de paládio preparadas em meio de líquido iônico: preparação, caracterização e aplicação
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Data
2023-10-17
Autores
Carneiro, Nicollas Azevedo [UNIFESP]
Orientadores
Camilo, Fernanda Ferraz [UNIFESP]
Tipo
Trabalho de conclusão de curso de graduação
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Resumo
Neste trabalho, apresentamos um método inovador para a síntese de nanopartículas de paládio (PdNPs) usando o líquido iônico cloreto de 1-butil-3-metilimidazólio (BMImCl) como solvente, agente estabilizante e molde. As nanopartículas de Pd (PdNPs) foram obtidas a partir da redução química de soluções de PdCl2 em BMImCl em três diferentes concentrações: 10, 50 e 100 mM. O tetraidroborato de tetrabutilamônio (TBABH4), solubilizado no mesmo líquido iônico, foi introduzido como agente redutor para os íons Pd2+. A conversão para PdNPs foi evidenciada por análise espectroscópica e confirmada por microscopia eletrônica de transmissão, que revelou partículas esféricas com diâmetros menores que 5 nm, um tamanho considerado pequeno, o que pode contribuir para uma maior eficiência catalítica. Subsequentemente, combinamos celulose solubilizada em BMImCl com as PdNPs, regenerando-as em membranas. Essas membranas contêm teores de paládio variando de 0,03 a 8,0 % em massa e apresentam alta estabilidade térmica. Além disso, são insolúveis em ambientes aquosos e foram eficazmente empregadas como catalisadores heterogêneos em reações de acoplamento C-C Suzuki-Miyaura sem o uso de ligantes. A incorporação de PdNPs em membranas de celulose traz benefícios como redução de custos, facilitação nos processos de isolamento e potencial reutilização, comparativamente aos catalisadores tradicionais à base de Pd.
In this work, we present an innovating method for palladium nanoparticles (PdNPs) synthesis using the ionic liquid 1-buthyl-3-methylimidazolium chloride (BMImCl) as solvent, stabilizing agent and mold. The palladium nanoparticles (PdNPs) were obtained by the chemical reduction of PdCl2 in BMImCl in three different concentrations: 10, 50 and 100 mM. Tetrabutylammonium tetrahydroborate (TBABH4), solubilized in the same ionic liquid, was introduced as the reducing agent to the Pd2+ ions. The conversion to PdNPs was evidenced by spectroscopic analysis and confirmed by transmission electronic microscopy, which revealed spherical particles with diameters lower than 5 nm, which is considered a small size, and could contribute to higher catalytic efficiency. Subsequently, we combined solubilized cellulose in BMImCl with the PdNPs, regenerating in membranes. These membranes have palladium contents varying from 0,03 to 8,0 % in mass and display high thermal stability. Besides, they are insoluble in aqueous media and were efficiently used as heterogeneous catalysts in ligand-free Suzuki-Miyaura C-C coupling reactions. The incorporation of PdNPs in cellulose membranes brings advantages such as cost reduction, easy isolation processes and potential reusability, comparatively to the traditional Pd based catalysts.
In this work, we present an innovating method for palladium nanoparticles (PdNPs) synthesis using the ionic liquid 1-buthyl-3-methylimidazolium chloride (BMImCl) as solvent, stabilizing agent and mold. The palladium nanoparticles (PdNPs) were obtained by the chemical reduction of PdCl2 in BMImCl in three different concentrations: 10, 50 and 100 mM. Tetrabutylammonium tetrahydroborate (TBABH4), solubilized in the same ionic liquid, was introduced as the reducing agent to the Pd2+ ions. The conversion to PdNPs was evidenced by spectroscopic analysis and confirmed by transmission electronic microscopy, which revealed spherical particles with diameters lower than 5 nm, which is considered a small size, and could contribute to higher catalytic efficiency. Subsequently, we combined solubilized cellulose in BMImCl with the PdNPs, regenerating in membranes. These membranes have palladium contents varying from 0,03 to 8,0 % in mass and display high thermal stability. Besides, they are insoluble in aqueous media and were efficiently used as heterogeneous catalysts in ligand-free Suzuki-Miyaura C-C coupling reactions. The incorporation of PdNPs in cellulose membranes brings advantages such as cost reduction, easy isolation processes and potential reusability, comparatively to the traditional Pd based catalysts.