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Previous issue date: 2008 / Sólidos ácidos e básicos micro e nanoestruturados foram sintetizados e
aplicados em reação de transesterificação de óleo de soja para produção de biodiesel usando metanol. Os catalisadores ácidos Si/Zr foram sintetizados por duas rotas distintas, a fim de obter um material com mesoporos hexagonais direcionados (SiZrD) e não direcionados (SiZr). Os catalisadores
básicos foram obtidos por imobilização de tetrametilguanidina em sílica gel através de duas rotas sintéticas, obtendo sílica mesoporasa hexagonal (CatGD) e sílica amorfa (CatG). Dados de FTIR, 13C e 29Si RMN, difração de raios-X confirmaram o sucesso das sínteses propostas. Imagens MEV para o
CatGD mostraram uma estrutura polidispersa com nanopartículas inferiores a 100 nm, e para o CatG microesferas bastante uniformes com dimensões de 1 μm. SiZrD e SiZr apresentaram partículas dispersas bastante homogêneas com diâmetro 100 nm e 200 nm, respectivamente. Todos os materiais apresentaram excelente atividade catalítica para produção de biodiesel a partir de transesterificação de óleo de soja. Os catalisadores apresentaram rendimentos em 3 h de reação a 800C de 68,0%, 86,0%, 62,0% e 96,0%, respectivamente para CaGD, CatG, SiZrD e SiZr. Todos os catalisadores
foram recuperados e reutilizados por mais oito vezes, e todos os materiais mantiverem sua atividade catalítica, o que comprova a grande versatilidade e a viabilidade destes sólidos catalisadores. ___________________________________________________________________________________________ ABSTRACT / Acid and basic micro and nanostructured solids were synthesized and applied to the transesterification reactions of soybean oil for biodiesel production. Acidic solid catalysts Si/Zr were synthesized by two distinct routes in order to obtain a material with controlled hexagonal mesoporous (SiZrD) and an other with uncontrolled porous diameter (SiZr). Basic solid catalysts were obtained by immobilization of tetramethylguanide on silica gel through two routes, thus
preparing to obtain controlled hexagonal mesoporous silica (CatGD) and amorphous silica (CatG) catalysts. FTIR, 13C and 29Si NMR, and X-ray diffraction confirmed the success of the synthesis. SEM images showed that the CatGD structure presented polydispersed nanoparticles smaller than 100
nm, and CatG presented highly uniform microspheres, with particle sizes of the
individual particles about 1 μ m. Images ofSiZrD and SiZr showed particles that are homogeneously dispersed with mean particle diameters 100 nm and 200 nm, respectively. All materials showed excellent catalytic activity in producing biodiesel from the transesterification of soybean oil. The yields in 3 h of reaction at 800C were 68.0%, 86.0%, 62.0% and 96.0% for CaGD, CatG,
SiZrD and SiZr catalysts, respectively. All catalysts were recovered and reused more than eight times, and all materials maintained their catalytic efficiencies,
which attests to the great versatility and viability of these solid catalysts.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.unb.br:10482/3633 |
| Date | January 2008 |
| Creators | Faria, Elaine Alves de |
| Contributors | Prado, Alexandre Gustavo Soares do, Suarez, Paulo Anselmo Ziani |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | Portuguese |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Source | reponame:Repositório Institucional da UnB, instname:Universidade de Brasília, instacron:UNB |
| Rights | info:eu-repo/semantics/openAccess |
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