Estudos de complexos de estanho (IV) contendo ligantes ALQUIL, cloro ou hidróxido em reações de obtenção de ésteres metílicos de ácidos graxos

Detalhes bibliográficos
Ano de defesa: 2015
Autor(a) principal: Nunes, Rafael Saraiva
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 Alagoas
Brasil
Programa de Pós-Graduação em Química e Biotecnologia
UFAL
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://www.repositorio.ufal.br/handle/riufal/1893
Resumo: In order to produce alternative fuels derived from renewable resources (biomass) and environmentally friendly, it was investigated in this work the catalytic activity of three metal complexes showing Lewis acid character: Butyltin chloride dihydroxide (BCDH-Sn), Butyltintrichloride (BTC-Sn) and dibutyltin dichloride (DBDC-Sn).These complexes were tested for catalytic soybean oil methanolysis and esterification of oleic acid in order to obtain a mixture of Fatty Acid Alkyl-Esters, when it is used as a fuel known as biodiesel. In methanolysis experiments, the reactions were performed in a glass reactor equipped with a reflux condenser or a closed reactor. The reactions were performed at temperatures ranging from 80 ° C, 120 ° C and 150 ° C, and the reaction time ranged from 15 minutes to 10 hours. The reaction products, obtained by transesterification, were analyzed by gas chromatography with flame ionization detector (GC-FID). In case of esterification of the oleic acid, was subjected to the same conditions of methanolysis using only the closed reactor. In this case, monoester analysis content was determined by acid-base titration. For characterization of catalysts, spectroscopic techniques were used in infrared and nuclear magnetic resonance. To determine reaction mechanism (trans) esterification, a set of reactions were made with subsequent NMR study 1H and 119Sn. In transesterification, the sequence in terms of catalytic efficiency was: BTC-Sn>BCDHSn>DBDC-Sn. In the esterification, the sequence was: BTC- Sn> DBDC -Sn>BCDHSn. These reactive differences were attributed to factors such as steric hindrance, catalyst solubility in reaction environment, interactions between the catalyst and substrate reaction and the acid strength of the catalysts. RMN's results of 1H and 119Sn indicated that the reactions of transesterification and esterification using three organometallic complexes of tin occur through Lewis´s acid-base mechanism.