Mesoporous materials are promising structures for application in catalysis and adsorption due to high surface area and large pore size. Mesoporous materials were synthesized by the hydrothermal method with novel surfactants, distinct from those observed in the literature, in order to carry out a study of its structure and to obtain materials with better textural properties. The structures synthesized with the surfactants Igepal CO630 and Brij O20 presented the best results of specific surface area, 1074 and 1075 m2.g-1, respectively. The obtained materials were characterized by XRD, TG/DTG, N2 adsorption-desorption, and FTIR techniques. XRD patterns indicated that the highly ordered mesoporous silica structures, such as MCM-41 and MCM-48, using CTMABr as the structure-directing agent and the SBA-15, SBA-16 and other SBA structures using different block copolymers were obtained. Through N2 adsorption-desorption isotherms, it was observed type IV isotherms, attributed to mesoporous materials. The FTIR spectra presented similar behaviors with characteristic vibrational bands of MCM and SBA type materials.
The possibility of crystallization of ZSM-5 with high Si/Al ratio was evaluated through the combined use of crystallization seeds and organic compounds that are not conventional directing agents for ZSM-5 (ethanol, methylamine, ethylamine, propylamine, butylamine, isopropylamine and diethylamine) in order to find a less toxic and costly route of synthesis. In addition, the influence of the stirring during the crystallization step on the properties of the ZSM-5 obtained in these synthesis conditions was verified. The obtained zeolites were analyzed by X-ray diffractometry in order to understand the effects of the templates. The analyses of NH3-TPD, nitrogen adsorption, SEM, and TG/DTA were performed for the samples with better crystallinity. The procedure was successfully employed for the synthesis of MFI samples using propylamine as an alternative structure-directing agent. Its mean crystallite size ranged from 23 to 24 nm and was efficient in the cracking reaction of n-hexane.
RESUMODevido a sua alta estabilidade térmica e acidez, a zeólita mordenita é utilizada como adsorvente na separação de gases ou misturas líquidas, e como catalisador nos processos de hidrocraqueamento, hidroisomerização, alquilação, reforma catalítica, desparafinação e síntese de dimetilaminas. A busca por novas propriedades das zeólitas conhecidas, a redução do tempo de cristalização e dos custos dos reagentes, torna o processo de síntese uma etapa crucial para sua viabilidade comercial. Este trabalho teve como finalidade destacar a importância do desenvolvimento de rotas para obtenção da mordenita, visto seu potencial de aplicação na indústria petroquímica. Para tanto, se desenvolveu uma fundamentação teórica a partir de patentes e artigos acessíveis nas bases de dados do INPI, Espacenet, WIPO, USPTO e Periódicos Capes. Como resultados destas análises foram estabelecidas as tendências para obtenção da zeólita mordenita.Palavras chave: Zeólita. Síntese. Mordenita. Sementes. ABSTRACTDue to its high thermal stability and acidity mordenite zeolite is used as adsorbent for the separation of gas or liquid mixtures, and as catalyst in processes of hydrocracking, hydroisomerization, alkylation, catalytic reforming, dewaxing and dimethylamines synthesis. The search for new properties of the known zeolites, the reduction of the crystallization time and cost of reagents, synthesis makes the process a critical step for its commercial viability. This work aimed to highlight the importance of developing routes to achieving mordenite, as their application potential in the petrochemical industry. Therefore, it has developed a theoretical framework from patents and accessible articles in the databases of the INPI, Espacenet, WIPO, USPTO and Portal periodicos Capes. As a result of these analyzes were established trends to obtain the mordenite zeolite.
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