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Avalia??o do comportamento termoanal?tico e oxidativo do biodiesel de mamona / Evaluation of the thermoanalytic and oxidative behavior of the castor biodiesel

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Previous issue date: 2006-12-18 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / In this work biodiesel was gotten through the transesterification reaction using the oil of castor as source of triglycerides and using the methylic route for
obtaining of esters. For the characterization of biodiesel and its mixtures with mineral diesel oil, physical chemical parameters and several analytical techniques had been used, as well as: gas chromatography (GC), nuclear magnetic resonance of proton (1H NMR), infrared spectroscopy (IR) and thermal analysis. The chromatography confirmed the complete reaction of esters in biodiesel presenting a 97,08% conversion. The 1H - NMR presented singlet in 3,6 ppm corresponding to the hydrogen of the group ester RCOO
CH3. The infrared presented a strong band in 1741 cm-1 referring to stretching C=O of ester and an average band in 1175 cm-1 referring C O deformation. With the data of thermal analysis it was possible to observe the thermal and
oxidative stability of the samples changing the atmospheres of synthetic air and nitrogen, where stages of the thermal decomposition had been verified and had been attributed to the volatilization and/or decomposition of the triacylglycerides. The thermal degradation of the samples was carried through 150 and 210?C during 1, 12, 24 and 48 hours and was observed change in the thermogravimetric profile, therefore an increase in the number of stages of the
thermal decomposition also occurred indicating characteristic intermediate composites of polymerization, being this confirmed through the rheological study that presented brusque increase of viscosity. The kinetic study showed
that the activation energy has the following order: biodiesel > mineral diesel oil > mixtures biodiesel/diesel / Neste trabalho o biodiesel foi obtido atrav?s da rea??o de
transesterifica??o usando o ?leo de mamona como fonte de triglicer?deos e utilizando a rota met?lica para obten??o dos ?steres. Para a caracteriza??o do biodiesel e das suas misturas com o diesel mineral foram utilizados par?metros
f?sico qu?micos e v?rias t?cnicas anal?ticas, como: cromatografia em fase gasosa (CG), resson?ncia magn?tica nuclear de pr?tons (RMN 1H), espectrofotometria na regi?o do infravermelho (IV) e an?lise t?rmica. A cromatografia confirmou a rea??o completa dos ?steres em biodiesel
apresentando uma convers?o de 97,08%. O RMN 1H apresentou o singlete em 3,6 ppm correspondente aos hidrog?nios do grupo ?ster RCOO CH3. J? o infravermelho apresentou uma banda forte em 1741 cm-1 referente ao
estiramento C=O do ?ster e uma banda m?dia a 1175 cm-1 referente a deforma??o C-O. Com os dados de an?lise t?rmica foi poss?vel observar a estabilidade t?rmica e oxidativa das amostras variando as atmosferas de ar sint?tico e nitrog?nio, onde foram verificadas etapas da decomposi??o t?rmica
que foram atribu?das ? volatiliza??o e/ou decomposi??o dos triacilglicer?deos. A degrada??o t?rmica das amostras foi realizada a 150 e 210?C por 1, 12, 24 e 48 horas e foi observado mudan?a no perfil termogravim?trico, pois ocorreu um aumento no n?mero de etapas da decomposi??o t?rmica indicando compostos intermedi?rios caracter?sticos de polimeriza??o, sendo este fato tamb?m confirmado atrav?s do estudo reol?gico que apresentou aumento brusco de
viscosidade. O estudo cin?tico realizado mostrou que a energia de ativa??o tem a seguinte ordem: biodiesel do ?leo de mamona > diesel > misturas biodiesel/diesel mineral

Identiferoai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/17586
Date18 December 2006
CreatorsFarias, Mirna Ferreira de
ContributorsCPF:42314070453, http://lattes.cnpq.br/1595902438130772, Ara?jo, Ant?nio Souza de, CPF:35530502415, http://lattes.cnpq.br/9770622597949866, Souza, Antonio Gouveia de, CPF:15760715453, http://lattes.cnpq.br/7481128465396350, Concei??o, Marta Maria da, Fernandes J?nior, Valter Jos?
PublisherUniversidade Federal do Rio Grande do Norte, Programa de P?s-Gradua??o em Qu?mica, UFRN, BR, F?sico-Qu?mica; Qu?mica
Source SetsIBICT Brazilian ETDs
LanguagePortuguese
Detected LanguageEnglish
Typeinfo:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis
Formatapplication/pdf
Sourcereponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN
Rightsinfo:eu-repo/semantics/openAccess

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