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.
Cage-based small-pore catalysts for NH3-SCR prepared by combining bulky organic structure directing agents with modified zeolites as reagents