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Previous issue date: 2013-03-22 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Different types of heterogeneous catalysts of the silicoaluminophosphate type, (SAPO-5, SAPO-11, SAPO-31, SAPO-34 and SAPO-41), molecular sieves with a: AFI, AEL, ATO, CHA and AFO structure, respectively, were synthesized through the hydrothermal method. Using sources such as hydrated alumina (pseudobohemita), phosphoric acid, silica gel, water, as well as, different types of organic structural templates, such as: cetyltrimethylammonium bromide (CTMABr), di-isopropylamine (DIPA), di-n- propylamine (DNPA) and tetraethylammonium hydroxide (TEOS), for the respective samples. During the preparation of the silicoaluminophosphates, the crystallization process of the samples occurred at a temperature of approximately 200 ? C, ranging through periods of 18-72 h, when it was possible to obtain pure phases for the SAPOs. The materials were furthermore washed with deionized water, dried and calcined to remove the molecules of the templates. Subsequently the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), absorption spectroscopy in the infrared region (FT-IR), specific surface area and thermal analysis via TG/DTG. The acidic properties were determined using adsorption of n-butylamine followed by programmed termodessorption. These methods revealed that the SAPO samples showed a typically weak to moderate acidity. However, a small amount of strong acid sites was also detected. The deactivation of the catalysts was conducted by artificially coking the samples, followed by n-hexane cracking reactions in a fixed bed with a continuous flow micro-reactor coupled on line to a gas chromatograph. The main products obtained were: ethane, propane, isobutene, n-butane, n-pentane and isopentane. The Vyazovkin (model-free) kinetics method was used to determine the catalysts regeneration and removal of the coke / Diferentes tipos de catalisadores heterog?neos do tipo silicoaluminofosf?tico, (SAPO-5, SAPO-11, SAPO-31, SAPO-34 e SAPO-41), peneiras moleculares com estrutura: AFI, AEL, ATO, CHA e AFO, respectivamente, foram sintetizados pelo m?todo hidrot?rmico. Utilizando-se de fontes como ? alumina hidratada (pseudobohemita), ?cido fosf?rico, s?lica gel, ?gua e diferentes tipos de direcionadores estruturais org?nicos, tais como o: brometo de cetiltrimetilam?nio (CTMABr), di-isopropilamina (DIPA), di-n-propilamina (DNPA) e hidr?xido de tetraetilam?nio (TEOS), nas respectivas amostras. Durante a prepara??o dos silicoaluminofosfatos o processo de cristaliza??o das amostras ocorreu ? temperatura de aproximadamente 200 ?C, durante per?odos que variaram de 18-72 h, quando foi poss?vel obter as fases puras dos SAPOs. Os materiais obtidos foram lavados com ?gua deionizada, secos e calcinados para a remo??o das mol?culas dos direcionadores. Posteriormente, as amostras foram caracterizadas por difra??o de raios-X (DRX), microscopia eletr?nica de varredura (MEV), espectroscopia de absor??o na regi?o do infravermelho (FT-IR), ?rea de superf?cie espec?fica e an?lise t?rmica via TG/DTG. As propriedades ?cidas foram determinadas usando adsor??o de n-butilamina seguida de termodessor??o programada. Esses m?todos revelaram que ?s amostras dos SAPOs apresentaram uma acidez tipicamente fraca a moderada. Entretanto, uma pequena quantidade de s?tios ?cidos fortes foi tamb?m detectada. A desativa??o dos catalisadores foi conduzida pelo coqueamento artificial das amostras, seguidas das rea??es de craqueamento do n-hexano em um microrreator catal?tico de leito fixo com fluxo cont?nuo acoplado em linha com um cromat?grafo a g?s. Como principais produtos foram obtidos: etano, propano, isobutano, n-butano, n-pentano e isopentano. Para determinar a regenera??o do catalisador e a remo??o do coque foi aplicado o m?todo cin?tico Vyazovkin (Model Free Kinetics) / 2020-02-01
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/12812 |
| Date | 22 March 2013 |
| Creators | Chellappa, Thiago |
| Contributors | CPF:42314070453, http://lattes.cnpq.br/1595902438130772, Melo, Dulce Maria de Ara?jo, CPF:06117988320, http://lattes.cnpq.br/3318871716111536, Curbelo, Fab?ola Dias da Silva, CPF:87599651420, http://lattes.cnpq.br/6991333478380004, Melo, Marcus Ant?nio de Freitas, CPF:04514998320, http://lattes.cnpq.br/5840621182000517, Nascimento, Rubens Maribondo do, CPF:80732810400, http://lattes.cnpq.br/8671649752936793, Parsekian, Val?ria Longo, CPF:18110772854, Fernandes J?nior, Valter Jos? |
| Publisher | Universidade Federal do Rio Grande do Norte, Programa de P?s-Gradua??o em Ci?ncia e Engenharia de Materiais, UFRN, BR, Processamento de Materiais a partir do P?; Pol?meros e Comp?sitos; Processamento de Materiais a part |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Format | application/pdf |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/embargoedAccess |
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