Organic structure-directing agents in SAPO synthesis: the case of 2-ethyl-1,3,4-trimethylimidazolium
Structure direction is a key topic in zeolite synthesis. In this work, the organic cation 2‐ethyl‐1,3,4‐trimethylimidazolium was studied for the first time in the synthesis of SAPO zeolite. Concentrated gels and fluoride media were chosen for the synthesis. To understand the formation of the main pr...
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| Principais autores: | , |
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| Formato: | article |
| Idioma: | English |
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Wiley
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| Endereço do item: | https://repositorio.ufrn.br/jspui/handle/123456789/29591 |
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| Resumo: | Structure direction is a key topic in zeolite synthesis. In this work, the organic cation 2‐ethyl‐1,3,4‐trimethylimidazolium was studied for the first time in the synthesis of SAPO zeolite. Concentrated gels and fluoride media were chosen for the synthesis. To understand the formation of the main products, CHA and LTA zeotypes, several statistical calculi were performed, and the results showed that the structure direction of the LTA zeotype was mainly caused by to the organic cation. For SAPO‐CHA, the temperature and a combination of dilution and synthesis time also influenced the formation. The CHA zeotype was studied thoroughly by other techniques such as thermogravimetry, high‐power decoupled (HPDEC) magic‐angle spinning (MAS) NMR spectroscopy, and nitrogen sorption. We calculated that this zeotype contains one cation per unit cell and observed that the fluoride medium also directs the structure. The silicon atoms in SAPO‐CHA are present in three states [SiO(4X), SiO(3X), and SiO(1X)], aluminium atoms were found in tetrahedral and octahedral coordination environments, and the phosphorus atoms also had tetrahedral geometries. Textural analysis confirmed the formation of a microporous material with a Brunauer–Emmett–Teller (BET) surface are of 510 m2 g–1 and an external surface of 110 m2 g–1 |
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