Zeolite Synthesis Using Imidazolium Cations as Organic Structure-Directing Agents

Featured Application This mini-review presents a case study about the research performed on zeolite synthesis with imidazolium derivatives as OSDAs at the Molecular Sieves Laboratory (LABPEMOL, Federal University of Rio Grande do Norte-UFRN). To do so, we first describe a quick overview of imidazolium derivatives and what is being done in other laboratories, after which we summarize the main results obtained at LABPEMOL. Readers will find a bibliography to deepen their knowledge of synthesis and characterization techniques and to help design new projects involving the synthesis or application of the obtained materials based on the know-how reviewed here. Abstract Imidazolium-derivative cations are very interesting molecules used as organic structure-directing agents (OSDAs) for zeolite synthesis, widening the possibilities of new materials and applications in this research area. In this review, the studies performed at LABPEMOL using this kind of compound are presented after a quick overview on imidazolium derivatives. The first zeolite synthesis results that started this research study were obtained with 1-butyl-3-methylimidazolium chloride. Then, the design of new OSDAs based on the imidazolium cation, such as 1,2,3-triethylimidazolium, 2-ethyl-1,3-dimethylimidazolium and 1,2,3-triethyl-4-methylimidazolium, is reported. Afterwards, the structure-direction effect caused by the introduction of heteroatoms with already-published imidazolium derivatives (for example, the Al3+ insertion into zeolite frameworks with two different OSDAs and the silicoaluminophosphate (SAPO) synthesis using 2-ethyl-1,3,4 trimethylimidazolium cations) is discussed. Finally, we also present a quick overview of some achievements of other laboratories.