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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Estudo do c?tion org?nico 2-etil-1,3,4-trimetilimidaz?lio na s?ntese de ze?litas e ze?tipos

Melguizo, Paloma Vinaches 27 October 2017 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2018-01-23T13:48:59Z No. of bitstreams: 1 PalomaVinachesMelguizo_TESE.pdf: 9134510 bytes, checksum: e3a170bd2869b5f767093e13c9c343c8 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2018-01-24T14:26:28Z (GMT) No. of bitstreams: 1 PalomaVinachesMelguizo_TESE.pdf: 9134510 bytes, checksum: e3a170bd2869b5f767093e13c9c343c8 (MD5) / Made available in DSpace on 2018-01-24T14:26:28Z (GMT). No. of bitstreams: 1 PalomaVinachesMelguizo_TESE.pdf: 9134510 bytes, checksum: e3a170bd2869b5f767093e13c9c343c8 (MD5) Previous issue date: 2017-10-27 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Nesta tese de doutorado estudou-se o agente direcionador de estrutura 2-etil-1,3,4- trimetilimidaz?lio no contexto da s?ntese de ze?litas e ze?tipos em meio fluoreto. Inicialmente, foi realizado um estudo aprofundado da ze?lita pura silica HPM-1 para o entendimento do papel do c?tion na nuclea??o e crescimento zeol?tico, conseguindo explicar a forma??o dos canais helicoidais e a ordem de apari??o das unidades secund?rias de constru??o. Subsequentemente, foi empregada uma metodologia de introdu??o de hetero?tomos em HPM-1 para proporcionar propriedades catal?ticas a esta, nunca tendo sido empregada o presente m?todo nesta topologia zeol?tica anteriormente. Como resultado, obtiveram-se tr?s materiais Al-HPM-1 diferentes, que foram caracterizados e testados na rea??o de dehidrata??o de etanol. Finalmente, foi realizado um estudo explorat?rio do c?tion org?nico em s?ntese de ze?tipos (com Si, Al e P), resultando em duas fases SAPO: os ze?tipos CHA e LTA. Foi comprovado que a estrutura SAPO-CHA foi direcionada n?o somente pelo emprego do composto org?nico e do meio fluoreto, mas sua obten??o foi devida ? temperatura e a uma combina??o de dilui??o e tempo. No caso do SAPO-LTA, o efeito direcionador foi consequ?ncia majoritariamente pelo emprego do c?tion org?nico. / In this doctoral thesis the structure-directing agent 2-ethyl-1,3,4-trimethylimidazolium was studied in the context of zeolite and zeotype synthesis in hydrofluoric media. Initially, it was deepened into the study of the pure silica zeolite HPM-1 to understand the role of the cation in the nucleation and growth, explaining the helical channels and the order of secondary building units formation. Subsequently, an alternative methodology of heteroatom introduction, never reported for the present material, was also presented to give HPM-1 catalytic properties. As a result of it, three different Al-HPM-1 samples were obtained, characterized and tested in ethanol dehydration reaction. Finally, an exploratory study of the organic cation in zeotype synthesis (with Si, Al and P) was performed, giving two main SAPO phases: CHA and LTA zeotypes. It was proven that the SAPO-CHA structure was directed not only by the use of the organic cation and the hydrofluoric media, but also its obtention was influenced by the temperature and a combination of dilution and time. In the case of the SAPO-LTA, the directing effect was mainly due to the organic cation.

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