Made available in DSpace on 2014-12-17T15:42:09Z (GMT). No. of bitstreams: 1 SolangeAQ_TESE.pdf: 2741616 bytes, checksum: ad21da6882b166123a02d610e3d096ef (MD5) Previous issue date: 2009-08-06 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The nanostructured molecular sieve SBA-15 was synthesized by the hydrothermal method, and modified with lanthanum with Si/La molar ratios of 25, 50, 75 and 100. The materials were evaluated as catalysts for the cracking of n-hexane model reaction. Type SBA- 15 and LaSBA-15 mesoporous materials were synthesized using tetraetilortosilicato as a source of silica, hydrochloric acid, heptahydrate lanthanum chloride and distilled water. Pluronic P123 triblock. polymer was used as structure template. The syntheses were carried out by 72 hours. The obtained SBA-15 samples were previously analyzed by thermogravimetry, in order to check the conditions of calcination for removal of organic template. Then, the calcined materials were characterized by X-ray diffraction, infrared spectroscopy, adsorption and desorption of nitrogen, scanning electron microscopy and X-ray microanalysis by dispersive energy. The acidity of the samples was determined using adsorption of n-bulinamina and desorption followed by thermogravimetry. It was found that the hydrothermal synthesis method was suitable for the synthesis of the SBA-15 mesoporous materials, with an excellent degree of hexagonal ordering. The reactions of catalytic cracking of n-hexane were carried out using a fixed bed continuous flow microreactor, coupled on-line to a gas chromatograph. From the catalytic evaluation, it was observed that the mesoporous materials containing lanthanum showed different results for the reaction of cracking of nhexane compared to the unmodified mesoporous material SBA-15. As a result of cracking was obtained as main products hydrocarbons in the range of C1 to C5. The catalyst that showed better properties in relation to the acidity and catalytic activity was LaSBA-15 with the ratio Si/La = 50 / A peneira molecular nanoestruturada SBA-15 foi sintetizada pelo m?todo hidrot?rmico, e modificada com lant?nio com raz?es molares Si/La de 25, 50, 75 e 100. Os materiais obtidos foram avaliados como catalisador para a rea??o modelo de craqueamento de n-hexano. Os materiais mesoporosos tipo SBA-15 e LaSBA-15 foram sintetizados utilizando tetraetilortosilicato, como fonte de s?lica, ?cido clor?drico, cloreto de lant?nio heptahidratado e ?gua destilada. Como direcionador estrutural foi utilizado copol?mero tribloco Pluronic P123. As s?nteses foram realizadas durante 72 horas. As amostras de SBA-15 modificadas foram avaliadas por termogravimetria para verificar as condi??es de calcina??o para remo??o do direcionador org?nico. Ap?s a retirada do direcionador as amostras de SBA-15 modificadas com diversas raz?es Si/La (25, 50, 75 e 100) foram caracterizadas por an?lises por difra??o de raios-X, espectroscopia na regi?o do infravermelho, adsor??o e dessor??o de nitrog?nio, microscopia eletr?nica de varredura e microan?lise de raios X por energia dispersiva. A acidez das amostras foi determinada utilizando adsor??o de n-bulinamina seguido de dessor?ao por termogravimetria. Verificou-se que o m?todo de s?ntese hidrot?rmica foi adequado ? s?ntese dos materiais mesoporosos modificados com excelente grau de ordena??o hexagonal. As rea??es de craqueamento catal?tico do n-hexano foram realizadas em um microreator catal?tico de leito fixo com fluxo cont?nuo acoplado em linha com um cromat?grafo a g?s. A partir da avalia??o catal?tica, foi observado que os materiais mesoporosos contendo lant?nio foram mais ativos que o SBA-15, para a rea??o de craqueamento do n-hexano, obtendo-se como produto hidrocarbonetos na faixa de C1 a C5. O catalisador que apresentou melhores propriedades, em rela??o ? acidez e a atividade catal?tica foi o sintetizado com a raz?o Si/La=50

Made available in DSpace on 2014-12-17T15:41:47Z (GMT). No. of bitstreams: 1 KesiaKV.pdf: 2272602 bytes, checksum: 46f23a52fbc9d4e74dfd9f25d2f58e11 (MD5) Previous issue date: 2009-02-19 / In present work, mesoporous materials of the M41S family were synthesized, which were discovered in the early 90s by researchers from Mobil Oil Corporation, thus allowing new perspectives in the field of catalysis. One of the most important members of this family is the MCM-41, which has a hexagonal array of mesopores with pore diameters ranging from 2 to 10 nm and a high surface area, enabling it to become very promising for the use as a catalyst in the refining of oil in the catalytic cracking process, since the mesopores facilitate the access of large hydrocarbon molecules, thereby increasing the production of light products, that are in high demand in the market. The addition of aluminum in the structure of MCM-41 increases the acidity of the material, making it more beneficial for application in the petrochemical industry. The mesoporous materials MCM-41 and Al-MCM-41 (ratio Si / Al = 50) were synthesized through the hydrothermal method, starting with silica gel, NaOH and distilled water. CTMABr was used as template, for structural guiding. In Al-MCM-41 the same reactants were used, with the adding of pseudoboehmite (as a source of aluminum) in the synthesis gel. The syntheses were carried out over a period of four days with a daily adjustment of pH. The optimum conditions of calcination for the removal of the organic template (CTMABr) were discovered through TG / DTG and also through analysis by XRD, FTIR and Nitrogen Adsorption. It was found that both the method of hydrothermal synthesis and calcination conditions of the studies based on TG were promising for the production of mesoporous materials with a high degree of hexagonal array. The acidic properties of the materials were determined by desorption of n-butylamine via thermogravimetry. One proved that the addition of aluminum in the structure of MCM-41 promoted an increase in the acidity of the catalyst. To check the catalytic activity of these materials, a sample of Atmospheric Residue (RAT) that is derived from atmospheric distillation of oil from the Pole of Guamar?- RN was used. This sample was previously characterized by various techniques such as Thermogravimetry, FTIR and XRF, where through thermal analysis of a comparative study between the thermal degradation of the RAT, the RAT pyrolysis + MCM-41 and RAT + Al- MCM-41. It was found that the Al-MCM-41 was most satisfactory in the promotion of a catalytic effect on the pyrolysis of the RAT, as the cracking of heavy products in the waste occurred at temperatures lower than those observed for the pyrolysis with MCM-41, and thereby also decreasing the energy of activation for the process and increasing the rates of conversion of residue into lighter products / No presente trabalho, foram sintetizados materiais mesoporos da fam?lia M41S que foram descobertos no in?cio dos anos 90 por pesquisadores da Mobil Oil Corporation, possibilitando assim novas perspectivas no ramo da cat?lise. Um dos mais importantes membros desta fam?lia ? o MCM-41, que possui um arranjo hexagonal de mesoporos com di?metros de poros entre 2 a 10 nm e uma alta ?rea superficial, tornando-o bastante promissor para ser utilizado como catalisador no refino do petr?leo para o craqueamento catal?tico, j? que seus mesoporos facilitam o acesso de mol?culas grandes de hidrocarbonetos, aumentando assim a produ??o de produtos leves com uma alta demanda no mercado. A adi??o de alum?nio na estrutura do MCM-41 aumenta a acidez do material, tornando-o mais positivo para aplica??o na ind?stria petroqu?mica. Os materiais mesoporosos do tipo MCM-41 e Al-MCM- 41 (raz?o Si/Al=50) foram sintetizados atrav?s do m?todo hidrot?rmico partindo da S?lica gel, NaOH e ?gua destilada. Como direcionador estrutural foi utilizado CTMABr. Para o Al- MCM-41 utilizaram-se os mesmos reagentes acrescentando a pseudobohemita (fonte de alum?nio) no gel de s?ntese. As s?nteses foram realizadas durante um per?odo de quatro dias com corre??o di?ria de pH. As melhores condi??es de calcina??o para remo??o do direcionador org?nico (CTMABr) foram otimizadas por TG/DTG e atrav?s de an?lises por DRX, FTIR e adsor??o de nitrog?nio verificou-se que tanto o m?todo de s?ntese hidrot?rmica como as condi??es de calcina??o baseado nos estudos por TG foram promissores para produ??o de materiais mesoporosos com alto grau de ordena??o hexagonal. As propriedades ?cidas dos materiais foram determinadas pela dessor??o de n- butilamina via termogravimetria. Comprovou-se que a adi??o de alum?nio na estrutura do MCM-41 promoveu um aumento na acidez deste catalisador. Para verificar a atividade catal?tica desses materiais utilizou-se uma amostra do Res?duo Atmosf?rico (RAT) que ? proveniente da destila??o atmosf?rica do petr?leo proveniente do P?lo de Guamar?- RN previamente caracterizado por v?rias t?cnicas como: Termogravimetria, FTIR e FRX, realizando-se atrav?s da an?lise t?rmica um estudo comparativo entre a degrada??o t?rmica do RAT, pir?lise do RAT+MCM-41 e RAT+Al-MCM-41. Verificou-se que o Al-MCM-41 promoveu um efeito catal?tico mais satisfat?rio na pir?lise do RAT, j? que o craqueamento dos produtos pesados presentes no res?duo ocorreu em temperaturas inferiores ?s observadas para a pir?lise com MCM-41 e com isso diminuindo tamb?m a energia de ativa??o para o processo, bem como aumentando os valores de convers?o do res?duo em produtos leves