Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-05-30T22:35:16Z No. of bitstreams: 1 JoaoPauloDaCostaEvangelista_TESE.pdf: 3170006 bytes, checksum: b1459f824b08153ad43dfbda6bced227 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-06-01T20:54:29Z (GMT) No. of bitstreams: 1 JoaoPauloDaCostaEvangelista_TESE.pdf: 3170006 bytes, checksum: b1459f824b08153ad43dfbda6bced227 (MD5) / Made available in DSpace on 2016-06-01T20:54:29Z (GMT). No. of bitstreams: 1 JoaoPauloDaCostaEvangelista_TESE.pdf: 3170006 bytes, checksum: b1459f824b08153ad43dfbda6bced227 (MD5) Previous issue date: 2015-07-22 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Esse estudo prop?s-se a obter biodiesel a partir da esterifica??o do ?cido oleico com os catalisadores Zr-SBA-15, Nb-SBA-15, SO42-/Zr-SBA-15 e SO42-/Nb-SBA-15 obtidos pela inser??o de Zr e Nb no suporte SBA-15 e sulfata??o do suporte impregnado. O suporte SBA-15 foi sintetizado pelo m?todo hidrot?rmico. O catalisador foi incialmente sintetizado pelo m?todo de impregna??o via ?mida, adicionando 4,2 mL de uma solu??o ? 30 % do percursor do metal (Zr e Nb) em cada grama da SBA-15. Ap?s a impregna??o foi realizado o processo de sulfata??o. As condi??es reacionais da s?ntese do biodiesel utilizadas nesse estudo foram: quantidade de catalisador (5% em massa), raz?o molar de metanol:?cido oleico (20:1), tempo reacional (8 h) e temperatura de refluxo (65?C). Os catalisadores foram analisados por: difra??o de raios-X (DRX), an?lise termogravim?trica (TG/DTG), espectroscopia de infravermelho por transformada de Fourier (FTIR), adsor??o/dessor??o de nitrog?nio, microscopia eletr?nica de varredura (MEV), espectroscopia de energia dispersiva (EDS) e teste de acidez para identifica??o da estrutura, composi??o e verifica??o da presen?a de s?tios ?cidos. Os resultados de caracteriza??o indicaram que o suporte SBA-15 preservou a estrutura hexagonal ordenada, ap?s a incorpora??o de Zr e Nb. Observou-se a presen?a de nanopart?culas desses metais dispersas na superf?cie e no interior dos canais microporosos e mesoporosos dos catalisadores Zr-SBA-15 e Nb-SBA-15. Ap?s a sulfata??o, aumentou a quantidade de s?tios ?cidos e a estrutura ordenada foi mantida. Para os catalisadores Zr-SBA-15 e SO42-/Zr-SBA-15 houve a forma??o das estruturas tetragonal e monocl?nica do ZrO2, j? para os demais catalisadores Nb-SBA-15 e SO42-/Nb-SBA-15 formaram-se estruturas amorfas. A atividade catal?tica foi avaliada pela rea??o de esterifica??o do ?cido oleico via rota et?lica, utilizando todos os catalisadores sintetizados. O biodiesel obtido com SO42-/Zr-SBA-15 apresentou propriedades f?sico-qu?micas dentro das normas especificadas pela resolu??o N?7/2008 da ANP e melhor rendimento com 80,7%. Foi verificado que os catalisadores sulfatados, produziram maior rendimento com rela??o aos n?o sulfatados. O suporte SBA-15 n?o apresentou atividade catal?tica. / Fatty acids such as oleic acid, have received particular attention as raw material, due to its abundance, availability and relatively high purity, being considered as potential materials for production of biodiesel. The esterification reaction of oleic acid using heterogeneous catalysts can be a promising alternative for biodiesel production. This study proposes to find a biodiesel through esterification of oleic acid with Zr-SBA-15, Nb-SBA-15, SO42?/Zr-SBA-15 and SO4 2?/Nb-SBA-15 catalysts, obtained by insertion of Zr and Nb in support SBA-15 and sulfation of the impregnated support. SBA-15 support was synthesized by hydrothermal method. Support SBA-15 was synthesized by hydrothermal method. The catalyst was initially synthesized by the wet impregnation method, followed by sulfation process. The catalysts were analyzed: X-ray diffraction (XRD), thermal analysis (TG/DTG), Fourier transform infrared spectroscopy (FTIR), nitrogen adsorption/desorption, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and acidity test to identify the structure, composition and verification the presence acid sites. The characterization results indicated that the SBA-15 support preserved the ordered hexagonal structure after the incorporation of Zr and Nb. It was observed the presence of nanoparticles these metal dispersed on the surface and within the microporous and mesoporous channels of Zr-SBA-15 and Nb-SBA-15 catalysts. After sulfation, increased amount of acid sites and the ordered structure was maintained. For Zr-SBA-15 and SO4 2?/Zr-SBA-15 catalyst was the formation of tetragonal and monoclinic structures of ZrO2, as for the other, Nb-SBA-15 and SO42?/Nb-SBA-15 catalyst were formed amorphous structures. The catalytic activity was evaluated by the esterification reaction of oleic acid via ethyl route, using all the synthesized catalysts. Biodiesel obtained with SO42?/Zr-SBA-15 presented physicochemical properties within the standards specified by the Resolution N? 45/2014 ANP and obtained the best yield with 80.7%. It was found that sulfated catalysts, produced higher yields with respect to nonsulfated. The SBA-15 support showed no catalytic activity.

Uma das desvantagens dos bio-óleos precursores do biodiesel é a alta carga de compostos oxigenados que diminuem seu poder de combustão, reduzindo sua eficiência e inviabilizando seu uso em larga escala. Nesse contexto, o processo de hidrodesoxigenação (HDO) é relevante, dado que elimina esses compostos através de uma reação catalítica e, portanto, aumenta o poder calorífico do combustível. Neste trabalho, estudou-se a HDO do guaiacol (2-metoxifenol) como composto modelo dos bio-óleos derivados da biomassa e avaliou-se o desempenho de catalisadores de Ni e Mo no processo. Estudou-se a performance de um catalisador suportado em SBA-15 - um material mesoporoso de sílica de alta área superficial - em comparação a de um catalisador tradicional suportado em gama-alumina. Para tal, utilizou-se um sistema contínuo em fase gasosa e reator de leito fixo. Utilizaram-se técnicas de caracterização de catalisadores, como adsorção de N2, MEV, MET, DRX, TPR-H2, FTIR, TPO-O2, Raman e TGA. Através das análises DRX e MET, comprovou-se que se formaram partículas de NiO e MoO3 de menor tamanho e mais dispersas no caso do catalisador de SBA-15, devido à menor interação com o suporte e maior área superficial, o que resultou em um grau de redução de 91,6 % deste catalisador, em comparação a 73,4 % do outro, analisados por TPR-H2. Os testes catalíticos mostraram que o catalisador de NiMo/SBA-15 supera o de alumina em termos de conversão no intervalo de 200 a 300 °C, com ciclohexeno e ciclohexano como principais produtos, em face à maior seletividade a catecol e fenol no NiMo/?-Al2O3. A 300 °C, o catalisador suportado em sílica alcançou taxas de 66,5 % para a HDO e 35,3 % HDA (hidrodesaromatização), enquanto o de alumina obteve somente 30,8 e 2,7 %, respectivamente. Finalmente, comprovou-se que o SBA-15 teve uma taxa de desativação por coque de 1,14 mgcoque gcat-1 h-1, 31 % menor que a taxa do catalisador de alumina, cujos depósitos foram de carbono grafítico bem estruturado e irreversível. Em vista dos resultados obtidos, esta dissertação apresenta as rotas e mecanismos de reação do guaiacol nos catalisadores estudados, conhecimento que é relevante para o desenvolvimento e aprimoramento de futuros catalisadores da HDO. / A key disadvantage of the bio-oils precursors of biodiesel is the high load of oxygenated compounds that reduce their heat of combustion, dropping their efficiency and making them unfeasible on a large scale. In light of that, the hydrodeoxygenation process (HDO) is relevant, since it eliminates these compounds through a catalytic reaction, thus increasing the calorific value of the fuel. In this work, the HDO of guaiacol (2-methoxyphenol) as a model compound of the bio-oils derived from biomass was studied and the performance of Ni-Mo catalysts was evaluated. A catalyst supported on SBA-15 - a high surface area mesoporous silica material - was compared to a traditional gamma-alumina-supported catalyst. For this purpose, a continuous gas phase setup with fixed bed reactor was employed. The catalysts properties were identified by N2 adsorption, SEM, TEM, XRD, H2-TPR, FTIR, O2-TPO, Raman and TGA techniques. Through XRD and TEM, it was verified that smaller and more dispersed NiO and MoO3 particles were formed in the case of the SBA-15 catalyst, due to the lower interaction with the support and the greater surface area, which resulted in a degree of reduction of 91.6% for this catalyst, as opposed to 73.4% for the other one, both analyzed by H2-TPR. The catalytic tests showed that the NiMo/SBA-15 outperforms the alumina catalyst in terms of conversion in the range of 200 to 300 °C, with cyclohexene and cyclohexane as main products, in contrast with major selectivity to catechol and phenol on NiMo/?-Al2O3. At 300 °C, the silica-supported catalyst achieved rates of 66.5% for HDO and 35.3% for HDA (hydrodearomatization), whereas alumina reached only 30.8 and 2.7%, respectively. Finally, it was shown that the SBA-15 catalyst had a coke deactivation rate of 1.14 mgcoke gcat-1 h-1, 31% lower than the alumina catalyst, whose coke deposits consisted of well-structured irreversible graphitic carbon. In view of the results, this dissertation proposes the routes and reaction mechanisms of guaiacol on the studied catalysts, knowledge that is pertinent for the development and improvement of future HDO catalysts.

This thesis deals with the study of several catalysts for the Fischer-Tropsch synthesis in the Biomass-To-Liquid process. In this work two groups of catalysts were tested. On the one hand, two series of catalysts with cobalt loadings of 6 and 12 wt% over SiO2 and some of them containing 5wt% of TiO2 were tested. One the other hand, other two series of mesoporous short channel SBA-15, all of them with cobalt loadings of 12wt% and some with 5wt% of titania. The first series was supported on SBA-15 DeWitte and the second one on SBA-15 Martinez. On the one hand, the influence of water addition to the feed, titania content and cobalt loading to the catalyst and was studied, as well as the consequences of a GHSV. The FT reaction was carried out along 5 periods of 24 hours each, in which conditions such as feed and water content were modified, enabling the study of these parameters. It was found that water provokes an increase of the CO conversion and has a positive kinetic effect on the rate to hydrocarbons. However, this fact reaction is followed by a quick deactivation, enhanced by high water partial pressures. Most of that deactivation is irreversible since it is not completely recovered after water removal. On the other hand, differences between the supports were studied. Some SBA-15 supported catalysts show CO diffusion limitations at longer channel lengths than what applies for conventional 3D porous supports. Titania grafting increases the rate to hydrocarbons, showing positive results for FT catalysts development.

Durante los últimos tiempos, una de las preocupaciones sociales ha estado relacionada con las consecuencias del consumo de tabaco sobre la salud de los fumadores activos y pasivos. De este modo, se han generado múltiples debates enfocados hacia la importancia de erradicar esta práctica. Sin embargo, las acciones adoptadas por los diferentes gobiernos, claramente no han sido suficientes. Éstas no han sido capaces de evitar los efectos negativos del tabaco y tampoco han alcanzado los valores esperados en la reducción del consumo. En este sentido, los procesos de adsorción y catálisis pueden proporcionar una alternativa valiosa para reducir la toxicidad del humo del tabaco, lo cual puede constituir un campo importante para una nueva aplicación en el uso de catalizadores. Nuestro grupo de investigación ha estado trabajando durante años en el uso de catalizadores, como la SBA-15, para reducir los niveles de compuestos tóxicos generados en el proceso de fumado y ayudar al consumidor a minimizar su adicción. Los trabajos realizados por el grupo anteriormente se centraron en la descripción del efecto de tales catalizadores en la química del humo del tabaco y su capacidad de reducción de tóxicos. También se ha estudiado el efecto sobre la nicotina y varios aditivos del tabaco. Son varios los autores que trabajan en esta vía, centrándose en las nitrosaminas y otros compuestos específicos. Sin embargo, en todos los trabajos de investigación, no se ha considerado la influencia de las propiedades de textura del catalizador en el rendimiento de la aplicación. En este sentido, el objetivo del presente trabajo es preparar materiales SBA-15 a diferentes temperaturas, tiempos y velocidades de agitación en las diferentes etapas de la síntesis, así como la simplificación de los equipos necesarios para el proceso. Se ha estudiado, además, el efecto de reducir el volumen de medio de reacción en el tratamiento hidrotérmico. De este modo, se pretende analizar la influencia de estas variables en la capacidad de reducción de compuestos tóxicos en el humo del tabaco. Asimismo, también se pretende analizar el efecto del reactivo fuente de sílice. En este trabajo se muestran datos de gran interés para seleccionar las condiciones de síntesis y ajustar las propiedades de materiales tipo SBA-15 para esta aplicación práctica de enorme repercusión potencial. Además de discutir aspectos que pueden simplificar y economizar su proceso a gran escala, se muestran los resultados preliminares de un proceso de producción de estos materiales a escala de kilogramos, lo que permite avanzar en la puesta a punto del proceso de fabricación a escala industrial.

Over the past decades, there have been worldwide efforts to synthesize new types of ordered porous materials for catalysis, separations, etc. Among those, mesoporous material with microporous walls are promising in a sense that while mesopores act as channels for the reactant transport with little diffusion limitation, micropores in the wall act as active sites for reactions or storage of the molecules. In this study, we focused on the SBA-15 material, which is a highly ordered mesoporous silica material with micropores present in the wall. We have studied the synthesis of the material by manipulating various factors that are known to have influence on the porous characteristic of the material. We have aimed our studies particularly on the micropores present in the material. Unlike zeolite materials, which have regular, well characterized pore structures, micropores in the SBA-15 are not ordered, thus may have a very broad pore size distribution. We have synthesized sets of mesoporous silica materials that have characteristics similar to those reported in the literature. Using microwave heating, we were able to synthesize the target material within a short period of time, about 10 to 12-fold reduction of the conventionally known synthesis time. The synthesized materials were initially characterized using XRD and SEM. Adsorption studies were then undertaken on the materials to determine the surface area and pore structure. The interpretation of micropores has heretofore been problematic and the models are ambiguous. Relatively simply ordered, 1-dimensional channel type, zeolite materials were also studied; MTW, MTT, TON, ATS, VET frameworks. Adsorption isotherms of these materials were obtained and simple empirical models were developed to determine the pore size distribution. Further, a sequential adsorption technique, using n-nonane as a preadsorbate, was used to evaluate the realistic external surface areas of zeolite materials and mesopore surface areas of micro-mesoporous materials. Applying this technique to “multidimensional pore system” will provide another way to obtain the realistic surface area and mesopore size distribution.

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La préparation de matériaux catalytiques, à base de métaux de transition (Ni, Co, Cu) supportés sur des supports à porosité organisée, performants pour la réaction d’hydrogénation chimiosélective du cinnamaldéhyde, a été étudiée. L’étude peut être divisée en deux parties distinctes, selon la nature du support, silicique ou aluminique. La première partie traite de la dispersion de métaux de transition sur des supports de type SBA-15.Dans le premier chapitre est présentée la préparation des catalyseurs par la méthode IWI-MD (Incipient Wetness Impregnation – Mild Drying). Plusieurs études, afin de valider l’efficacité de cette méthode, ont été menées : (i) influence de la texture du support, (ii) influence de la température et du temps de séchage; (iii) influence de la teneur en métal. Le deuxième chapitre rapporte l’étude de la préparation par la voie de déposition par précipitation. L’étude de la méthode d’infiltration des sels fondus, dite de Melt Infiltration (MI), optimisée afin d’assurer une infiltration complète du précurseur dans la porosité du support préalablement à la formation de la phase oxyde, est présentée dans le Chapitre 3. Finalement, le dernier chapitre du document traite de la dispersion sur des supports aluminiques mésoporeux ordonnés (AMO). Les matériaux catalytiques ont été préparés sur des supports AMO, obtenus par la voie d’auto-assemblage induit par évaporation (AAIE). Les paramètres étudiés sont : (i) l’effet de la texture du support, à partir d’alumines de différentes tailles de pores et (ii) l’effet du mode de déposition des métaux (par IWI-MD, MI ou TS). / The development of efficient transition metal based catalysts for the chemoselective hydrogenation reaction of cinnamaldehyde is studied. The active phases, studied in this work, are among the transition metals (Ni, Co and Cu), supported on porous ordered materials. This study can be divided in two different sections, according to the support nature. The first part concerns the dispersion of transition metals on SBA-15 type silica support. In the first chapter is presented the transition metal dispersion (Ni, Co and Cu) using IWI-MD (Incipient Wetness Impregnation –Mild Drying) method. Studies performed, to optimize active phase dispersion, are: (i) influence of support texture, (ii) influence of drying temperature, (iii) influence of drying time, (iv) influence of metal loading. In the second chapter, Ni, Co and Cu catalytic materials are prepared using deposition precipitation method. In the third chapter is described the transition metal dispersion using melt infiltration method (MI), optimized to ensure a complete infiltration of metallic precursors in the support porosity before oxide phase formation. The second section of the Ph.D. is related to the dispersion of transition metal over ordered mesoporous alumina (AMO) supports. Catalytic materials, based on Ni and Cu over AMO (obtained by EISA process - Evaporation Induced by Self-Assembly), are produced. Parameters studied are: effect of support texture, effect of preparation route (IWI-MD, MI and TS).