Made available in DSpace on 2014-12-17T15:42:16Z (GMT). No. of bitstreams: 1 LuizaPFCG_TESE.pdf: 3362653 bytes, checksum: 0de0a428d24980a5f9b2bf94d2e9214f (MD5) 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

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2015-11-27T15:27:52Z No. of bitstreams: 1 GiceliaRodrigues_TESE.pdf: 4017865 bytes, checksum: c0fa528988ec3e75c837780c20f66c73 (MD5) / Approved for entry into archive by Elisangela Moura (lilaalves@gmail.com) on 2015-11-30T23:51:12Z (GMT) No. of bitstreams: 1 GiceliaRodrigues_TESE.pdf: 4017865 bytes, checksum: c0fa528988ec3e75c837780c20f66c73 (MD5) / Made available in DSpace on 2015-11-30T23:51:12Z (GMT). No. of bitstreams: 1 GiceliaRodrigues_TESE.pdf: 4017865 bytes, checksum: c0fa528988ec3e75c837780c20f66c73 (MD5) Previous issue date: 2014-08-22 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Atualmente, o Brasil conta com grande potencial e boas perspectivas futuras para a manuten??o e amplia??o de sua matriz energ?tica. S?o exemplos de alternativas para o futuro, os petr?leos oriundos do pr?-sal, energias e?licas, hidrel?tricas, nuclear, al?m dos biocombust?veis. O est?mulo ? produ??o e ao consumo de bicombust?vel favorece mundialmente a pol?tica de preserva??o ao meio ambiente, contribuindo na redu??o dos gases, poluentes, causadores do efeito estufa e redu??o das altera??es clim?ticas. A presen?a de catalisadores nos processos de produ??o de bicombust?veis desempenha um importante papel na melhoria da rotas de produ??o, tais como: taxa de rea??o, rendimento e seletividade de produtos e co-produtos de alto valor agregado. A tend?ncia atual das pesquisas nesse campo foca no aprimoramento desses processos com o uso de catalisadores heterog?neos, visto que catalisadores heterog?neos apresentam vantagens significativas, tais como: menor contamina??o dos produtos, facilidade de separa??o do catalisador do meio reacional, possibilidade de reaproveitamento do catalisador, diminui??o dos problemas de corros?o. Portanto, pesquisas est?o sendo desenvolvidas para obten??o de materiais mesoporosos, que s?o catalisadores heterog?neos, devido ao fato de que esses materiais apresentam facilidade de s?ntese e s?o economicamente vi?veis, apresentam poros relativamente grandes que facilitam a acessibilidade de ?cidos graxos no interior das part?culas, minimizando resist?ncias ao transporte de massa. Ap?s montada matriz experimental para a s?ntese do Al-SBA-15, foi realizado a s?ntese hidrot?rmica do Al-SBA-15 com diferentes raz?es de Si/Al variando as quantidades estequiom?tricas dos materiais precursores.Os testes catal?ticos foram a rea??o de transesterifica??o utilizando como m?tria-prima o ?leo de coco bruto e a pir?lise. As rea??es de transesterifica??o foram realizadas em um reator Parr de a?o inoxid?vel, modelo 4523, equipado com agitador mec?nico, indicadores de temperatura e press?o. O tratamento cin?tico referente aos dados da pir?lise do ?leo de coco puro e do ?leo de coco com AlSBA-15, realizou-se por meio da utiliza??o de curvas termogravim?tricas (TG) obtidas em uma termobalan?a modelo TGA/SDT Q600 da TA instruments, nas seguintes taxas de aquecimento: 5,10 e 20?C min-1. O ?leo de coco bruto apresentou com uma mat?ria-prima apropriada para obten??o do biodiesel via rota et?lica e o catalisador sintetizado com as condi??es experimentais I, apresentou as melhores condi??es para a s?ntese de biodiesel. Os aspectos visuais e as caracter?sticas f?sico-qu?micas dos produtos da rea??o, mostram que o catalisador AlSBA-15 favoreceu a rea??o. De acordo com as analises f?sico-qu?micas a ordem de estabilidade oxidativa do produto da rea??o de transesterifica??o foi: 1500?C +AlSBA-15 > 100?C> 100?C + AlSBA-15> 200?C + AlSBA-15. / Stimulus encouraging the production and consumption of biodiesel favors the policy of pre-serving the environment, contributing to the reduction of greenhouse gas reducing climate change. The current trend of research in this field focuses on improving these processes with the use of heterogeneous catalysts, seeing has significant advantages such as: low contamination of products, ease of separation of the catalyst from the reaction medium, possibili-ty of reuse of the catalyst, decreased corrosion problems. The objective of this research was to optimize the synthesis of AlSBA-15 for the production of biodiesel through transesterification process via ethyl route. For the optimization of hydrothermal synthesis of type AlSBA-15 catalyst has assembled a 23 factorial experimental matrix with eleven trials. The stoichiometric amounts of starting materials were varied according to different ratios Si / Al which is a factor in the experimental design, in addition to the time and temperature of aging of the synthesis gel. The material showed the best results of characterization (SBET = 591.7 (m2 / g), Vp = 0.83 (cm3 / g), Dp = 5.59 (nm), w = 6.48 (nm) was synthesized at 100 ? C for 24 hours, with a ratio Si / Al = 10.This material was applied as a heterogeneous catalyst in the reaction of ethyl transesterification as raw coconut oil in natura. Coconut oil presented suitable for obtaining biodiesel via ethyl route.The visual aspects and physical-chemical characteristics of the reaction products show that AlSBA-15 catalyst favored the reaction. According to physical-chemical analysis the order of oxidative stability of the product of the transesterification reaction was: catalytic reaction at 1500 ? C> non-catalytic reaction at 100 ? C> 100 ? C catalytic> catalytic reaction at 200 ? C Reaction. The results of oxidative stability and kinematic viscosity shows that the biodiesel produced in the catalytic sandblasting held at 150 ? C which was maintained within the ABNT NBR 7148, ABNT NBR 10441 and EN 14112.