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Organic Structure‐Directing Agents in SAPO Synthesis: The Case of 2‐Ethyl‐1,3,4‐trimethylimidazolium
Author(s) -
Vinaches Paloma,
Pergher Sibele B. C.
Publication year - 2018
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201701002
Subject(s) - chemistry , microporous material , zeolite , octahedron , fluoride , inorganic chemistry , bet theory , sorption , hydrothermal synthesis , crystallography , thermogravimetry , mesoporous material , crystal structure , chemical engineering , organic chemistry , catalysis , adsorption , engineering , hydrothermal circulation
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 m 2 g –1 and an external surface of 110 m 2 g –1 .