Made available in DSpace on 2014-12-17T14:08:46Z (GMT). No. of bitstreams: 1 LarissaCLA_DISSERT.pdf: 2411784 bytes, checksum: bc6175bf8ed881abf12e8c0d17d59264 (MD5) Previous issue date: 2011-07-04 / Biodiesel is an alternative fuel, renewable, biodegradable and nontoxic. The transesterification of vegetable oils or animal fat with alcohol is most common form of production of this fuel. The procedure for production of biodiesel occurs most commonly through the transesterification reaction in which catalysts are used to accelerate and increase their income and may be basic, acid or enzyme. The use of homogeneous catalysis requires specific conditions and purification steps of the reaction products (alkyl ester and glycerol) and removal of the catalyst at the end of the reaction. As an alternative to improve the yield of the transesterification reaction, minimize the cost of production is that many studies are being conducted with the application of heterogeneous catalysis. The use of nano-structured materials as catalysts in the production of biodiesel is a biofuel alternative for a similar to mineral diesel. Although slower, can esterify transesterified triglycerides and free fatty acids and suffer little influence of water, which may be present in the raw material. This study aimed at the synthesis, characterization and application of nano-structured materials as catalysts in the transesterification reaction of soybean oil to produce biodiesel by ethylic route. The type material containing SBA-15 mesoporous lanthanum embedded within rightly Si / La = 50 was used catalyst. Solid samples were characterized by X-ray diffraction, thermogravimetric analysis, infrared spectroscopy, nitrogen adsorption and desorption. For the transesterification process, we used a molar ratio of 20:1 alcohol and oil with 0.250 g of catalyst at 60?C and times of 6 hours of reaction. It was determined the content of ethyl esters by H-NMR analysis and gas chromatography. It was found that the variable of conversion obtained was 80%, showing a good catalytic activity LaSBA-15 in the transesterification of vegetable oils via ethylic route / O biodiesel ? um combust?vel alternativo, renov?vel, biodegrad?vel e n?o t?xico. A transesterifica??o dos ?leos vegetais ou gordura animal com ?lcool ? a forma mais usual de produ??o desse combust?vel. O procedimento de produ??o de biodiesel ocorre mais comumente atrav?s da rea??o de transesterifica??o, na qual se utiliza catalisadores para acelerar e aumentar seu rendimento, podendo ser b?sico, ?cido ou enzim?tico. O uso da cat?lise homog?nea requer condi??es e etapas espec?ficas de purifica??o dos produtos da rea??o (?ster alqu?licos e glicerol) e remo??o do catalisador ao t?rmino da rea??o. Como alternativa para melhorar o rendimento da rea??o de transesterifica??o, minimizar os custos com a produ??o ? que muitos estudos est?o sendo realizados com aplica??o de cat?lise heterog?nea. O uso de materiais nano-estruturados como catalisadores na produ??o de biodiesel ? uma alternativa para obter um biocombust?vel semelhante ao diesel mineral. Mesmo sendo mais lentos, conseguem transesterificar os triglicer?deos e esterificar os ?cidos graxos livres, al?m de sofrerem pouca influ?ncia da ?gua, que possa estar presente na mat?riaprima. Este trabalho teve como objetivo a s?ntese, caracteriza??o e aplica??o de materiais nano-estruturados como catalisadores na rea??o de transesterifica??o de ?leo de soja, para obten??o de biodiesel pela rota et?lica. O material do tipo SBA-15 contendo lant?nio incorporado na estrutura mesoporosa, com raz?o Si/La=50, foi utilizado como catalisador. As amostras s?lidas foram caracterizadas por difra??o de raios-X, an?lise termogravim?trica, espectroscopia na regi?o do infravermelho, adsor??o e dessor??o de nitrog?nio. Para o processo de transesterifica??o, utilizou-se uma raz?o molar entre ?lcool e ?leo de 20:1 com 0,250 g de catalisador, temperatura de 60?C e tempos de 6 horas de rea??o. Determinou-se o teor de ?steres et?licos pela an?lise de H-RMN e cromatografia a g?s. Foi verificado que a vari?vel de convers?o obtida foi de 80%, mostrando uma boa atividade catal?tica do LaSBA- 15 na transesterifica??o do ?leo de soja via rota et?lica

Made available in DSpace on 2014-12-17T15:42:08Z (GMT). No. of bitstreams: 1 Geraldo Eduardo da Luz Junior_TESE.pdf: 1318067 bytes, checksum: bc521809cc7c08b9ef99f31a1034f3a2 (MD5) Previous issue date: 2010-04-26 / In order to obtain a biofuel similar to mineral diesel, lanthanum-incorporated SBA- 15 nanostructured materials, LaSBA-15(pH), with different Si/La molar ratios (75, 50, 25), were synthesized in a two-steps hydrothermal procedure, with pH-adjusting of the synthesis gel at 6, and were used like catalytic solids in the buriti oil thermal catalytic cracking. These solids were characterized by X-ray fluorescence (XRF), powder X-ray diffraction (XRD), thermogravimetric analysis (TG/DTG), infrared spectroscopy (FTIR), nitrogen porosimetry and ethanol dehydration, aiming to active sites identify. Taken together, the analyses indicated that the synthesis method has employed to obtain materials highly ordered mesostructures with large average pore sizes and high surface area, besides suggested that the lanthanum was incorporated in the SBA-15 both into the framework as well as within the mesopores. Catalytic dehydration of ethanol over the LaSBA-15(pH) products has shown that they have weak Lewis acid and basic functionalities, indicative of the presence of lanthanum oxide in these samples, especially on the La75SBA-15(pH) sample, which has presented the highest selectivity to ethylene. The buriti oil thermal and thermal catalytic cracking, realized from the room temperature to 450 ?C in a simple distillation system, has allowed obtaining two liquid fractions, each consisting of two phases, one aqueous and another organic, organic liquid (OL). The OL obtained from first fractions has shown high acid index, even in the thermal catalytic process. One the other hand, OL coming from second ones, called green diesel (GD), have presented low acid index, particularly that one obtained from the thermal catalytic process realized over LaSBA-15(pH) samples. The acid sites presence in these samples, associated to their large average pore sizes and high surface areas, have allowed them, especially the La75SBA-15(pH), to present deoxygenating activity in the buriti oil thermal catalytic cracking, providing an oxygenates content reduction, particularly carboxylic acids, in the GD. Furthermore, the GD comes from the second liquid fraction obtained in the buriti oil thermal catalytic cracking over this latest solid sample has shown hydrocarbons composition and physic-chemical properties similar to that mineral diesel, beyond sulfur content low / Com o objetivo de obter um biocombust?vel semelhante ao diesel mineral, materiais nano-estruturados do tipo SBA-15 com lant?nio incorporado, LaSBA-15(pH), com raz?es molares Si/La = 75, 50 e 25, foram sintetizados em dois est?gios, com ajuste do pH do gel de s?ntese a 6, e utilizados como s?lidos catal?ticos no craqueamento termocatal?tico de ?leo de buriti. As amostras s?lidas foram caracterizadas por fluoresc?ncia de raios-X (FRX), difra??o de raios-X (DRX), an?lise termogravim?trica (TG/DTG), espectroscopia na regi?o do infravermelho (FTIR), adsor??o-dessor??o de nitrog?nio e desidrata??o de etanol, para identifica??o dos s?tios ativos. Os resultados destas caracteriza??es indicaram que o m?todo de s?ntese empregado proporcionou a obten??o de materiais mesoestruturados altamente ordenados com grande di?metro m?dio de poros e elevada ?rea superficial, al?m de sugerir que o lant?nio foi incorporado na SBA-15 tanto no interior das paredes, quanto dentro dos mesoporos. A desidrata??o catal?tica de etanol sobre os s?lidos LaSBA-15(pH) mostrou que eles apresentam s?tios ?cidos e b?sicos de Lewis, indicativo da presen?a de ?xido de lant?nio nestes, especialmente na amostra La75SBA-15(pH), que apresentou a maior seletividade para etileno. Os craqueamentos t?rmico e termocatal?ticos do ?leo de buriti, realizados da temperatura ambiente a 450 ?C em um sistema de destila??o simples, possibilitaram a obten??o de duas fra??es l?quidas, compostas por duas fases, uma aquosa e outra org?nica, l?quido org?nico (LO). O LO obtido a partir das primeiras fra??es apresentou ?ndice de acidez muito elevado, at? mesmo nos processos termocatal?ticos. Por outro lado, o LO oriundo das segundas fra??es, denominado de diesel verde (DV), apresentou baixo ?ndice de acidez, particularmente aquele obtido nos processos realizados sobre as amostras LaSBA-15(pH). Os s?tios ?cidos presentes nestas amostras, associados aos seus grandes di?metros m?dios de poros e ?s elevadas ?reas superficiais, permitiram que elas, especialmente a La75SBA-15(pH), apresentassem atividade desoxigenante no craqueamento temocatal?tico do ?leo de buriti, ocasionando uma diminui??o da concentra??o de oxigenados no DV, particularmente ?cidos carbox?licos. Al?m disso, o DV obtido sobre esta ?ltima amostra s?lida apresentou composi??o de hidrocarbonetos e propriedades f?sico-qu?micas semelhantes ?s do diesel mineral, al?m de um baixo teor de enxofre