Catalisadores de nióbio com propriedades anfifílica empregados no estudo de transformação de biomassa

Detalhes bibliográficos
Ano de defesa: 2017
Autor(a) principal: Talita Evelyn de Souza
Orientador(a): Não Informado pela instituição
Banca de defesa: Não Informado pela instituição
Tipo de documento: Tese
Tipo de acesso: Acesso aberto
Idioma: por
Instituição de defesa: Universidade Federal de Minas Gerais
UFMG
Programa de Pós-Graduação: Não Informado pela instituição
Departamento: Não Informado pela instituição
País: Não Informado pela instituição
Palavras-chave em Português:
Link de acesso: http://hdl.handle.net/1843/SFSA-AM2N2H
Resumo: In this work, new catalysts based on niobium oxalate ammonium(NH4[NbO(C2O4)2(H2O)](H2O)n), niobium chloride (NbCl5) and niobium oxide (Nb2O5.nH2O) as precursor, were synthesized and characterized by controlled precipitation and hydrothermal synthesis. Amphiphilic catalysts were also synthesized in the presence of CTAB (cetyl trimethylammonium bromide), to apply in byphasic systems as glycerol:acetone on acetalization reactions, wich is the target in this work. Catalysts obtained by niobium oxalate ammonium, showed high acidity such as Nb2O5.nH2O, it decreases about 31 % by hydrophobization process, however improves glycerols conversion of 41 to 65%. Catalysts obtained by NbCl5, showed lower acidty than the other catalysts, but showed high BET specific area like 198 m2g-1 and presence of mesoporous, with good glycerol conversion results. In the same way, catalysts obtained by hydrothermal synthesis, showed high BET are, next to 192 m2g-1 and mesoporous structure. Differents niobium precursors and surfactant incorporation in the synthesis of the catalysts can exhibit different morphology, BET specific area and acidity. These properties act in the same time making a synergism and improve catalytic activities, mainly in biomass conversion reactions using biphasic systems.