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Previous issue date: 2012-08-23 / To overcome the challenge of meeting growing energy demand in a sustainable way,
biodiesel has shown very promising as alternative energy can replace fossil fuels, even
partially. Industrially, the biodiesel is produced by homogeneous transesterification reaction
of vegetable oils in the presence of basic species used as catalysts. However, this process is
the need for purification of the esters obtained and the removal of glycerin formed after the
reaction. This context, the alternative catalysts have that can improve the process of biodiesel
production, aiming to reduce costs and facilitate its production. In this study, the AlSBA-15
support with Si / Al ratio = 50 was synthesized, as like as the heterogeneous catalysts of zinc
oxide and magnesium supported on mesoporous AlSBA-15 silica, in the concentrations of 5,
10, 15 and 30 %, relative to the support. The textural properties and structural characterization
of catalysts and supports were determined by techniques: X-ray diffraction (XRD), scanning
electron microscopy (SEM), transmission electron microscopy (TEM) coupled to the
chemical analyzer, adsorption / desorption of N2, thermal analysis (TG / DTG), absorption
spectroscopy in the infrared (FTIR) and X-ray photoelectron spectroscopy (XPS).
Characterization results indicated that the support AlSBA-15 retained the hexagonal ordered
after the incorporation of zinc oxide and magnesium oxide in the holder. For heterogeneous
catalysts, ZnO-AlSBA-15, that was observed the presence of zinc oxide nanoparticles
dispersed in the surface and interior channels of the mesoporous and microporous support.
The catalytic activity was evaluated by the transesterification reaction of sunflower oil via
methylic route, and some reaction parameters were optimized with the most active catalyst in
biodiesel production by sunflower oil. For the series of heterogeneous catalysts, the sample
with 30 % ZnO supported on AlSBA-15 showed a better conversion of triglyceride to methyl
esters, about 95.41 % of reaction conditions: temperature 175 ?C, with molar ratio of 42:1,
stirring at 200 rpm and under a pressure of 14 bar for 6 h. The catalyst MgO-AlSBA-15
showed no catalytic activity in the studied reactions / Para superar o desafio de atender a crescente demanda por energia de forma sustent?vel, o
biodiesel tem se demonstrado bastante promissor como alternativa energ?tica, que possa
substituir os combust?veis fosseis, mesmo que parcialmente. Industrialmente, o biodiesel ?
produzido atrav?s de rea??o homog?nea de transesterifica??o de ?leos vegetais na presen?a de
esp?cies b?sicas utilizadas como catalisadores. Entretanto, este processo h? a necessidade de
purifica??o dos ?steres obtidos e a remo??o da glicerina formada ap?s a rea??o. Diante deste
contexto, tem-se buscado catalisadores alternativos, que possa aprimorar o processo de
produ??o de biodiesel, visando diminuir os custos e facilitar a sua produ??o. Neste trabalho,
foram sintetizados o suporte AlSBA-15 na raz?o Si/Al = 50, e os catalisadores heterog?neos
de ?xido de zinco e de magn?sio suportado sobre s?lica mesoporosa AlSBA-15, nas
concentra??o de 5, 10, 15 e 30 %, com rela??o ao suporte. As propriedades texturais e a
caracteriza??o estrutural dos catalisadores e do suporte foram determinadas pelas t?cnicas de:
difratometria de raios X (DRX), microscopia eletr?nica de varredura (MEV), microscopia
eletr?nica de transmiss?o (MET) acoplada ao analisador qu?mico, adsor??o/dessor??o de N2,
an?lise t?rmica (TG/DTG), espectroscopia de absor??o na regi?o do infravermelho (FTIR) e
espectroscopia fotoeletr?nica de raios X (XPS). Os resultados de caracteriza??o indicaram
que o suporte AlSBA-15 preservou a estrutura hexagonal ordenada, ap?s a incorpora??o do
?xido de zinco e do ?xido de magn?sio no suporte. Em rela??o aos catalisadores
heterog?neos, ZnO-AlSBA-15, observou-se a presen?a de nanopart?culas de ?xido de zinco
dispersas na superf?cie e no interior dos canais microporosos e mesoporosos do suporte. A
atividade catal?tica foi avaliada pela rea??o de transesterifica??o do ?leo de girassol via rota
met?lica, e alguns par?metros reacionais foram otimizados com o catalisador mais ativo na
produ??o de biodiesel pelo ?leo de girassol. Para as s?ries de catalisadores heterog?neos, a
amostra com 30 % ZnO suportado na AlSBA-15 apresentou melhor convers?o dos
triglicer?deos em ?steres met?licos, cerca de 95,41 %, nas condi??es reacional de: temperatura
de 175 ?C, com raz?o molar de 42:1, em agita??o de 200 rpm e sob press?o de 14 bar durante
6 h. O catalisador MgO-AlSBA-15 n?o apresentou atividade catal?tica nas rea??es estudadas
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/17756 |
| Date | 23 August 2012 |
| Creators | Galv?o, Luzia Patr?cia Fernandes de Carvalho |
| Contributors | CPF:42314070453, http://lattes.cnpq.br/1595902438130772, Ara?jo, Ant?nio Souza de, CPF:35530502415, http://lattes.cnpq.br/9770622597949866, Pergher, Sibele Berenice Castella, CPF:50942611004, http://lattes.cnpq.br/5249001430287414, Castell?n, Enrique Rodr?guez, Luz Junior, Geraldo Eduardo da, CPF:75648318391, http://lattes.cnpq.br/6484967625971729, Fernandes J?nior, Valter Jos? |
| Publisher | Universidade Federal do Rio Grande do Norte, Programa de P?s-Gradua??o em Qu?mica, UFRN, BR, F?sico-Qu?mica; Qu?mica |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Format | application/pdf |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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