Simple organic structure directing agents for synthesizing nanocrystalline zeolites

[EN] The synthesis of the ZSM-5 and beta zeolites in their nanosized form has been achieved by using simple alkyl-substituted mono-cationic cyclic ammonium cations as OSDA molecules. The particular combination of a cyclic fragment and a short linear alkyl-chain group (preferentially C4) within the monocationic OSDA molecules allows directing the crystallization of nanosized zeolites with excellent solid yields (above 90%). Interestingly, the formation of the nanosized ZSM-5 and beta zeolites mostly depends on the size and nature of the cyclic fragment of the OSDA molecule, resulting in all cases in nanocrystalline solids with homogeneous distributions of particle sizes (similar to 10-25 nm) and controlled Si/Al molar ratios (similar to 15-30). The achieved nanosized ZSM-5 and beta zeolites have been extensively characterized by different techniques to study their physico-chemical properties, such as chemical composition, pore accessibility or Bronsted acidity, among others. Moreover, the catalytic properties of the nanosized ZSM-5 and beta zeolites have been evaluated for different chemical reactions, including methanol-to-olefins (MTO) in the case of ZSM-5, and alkylation of benzene with propylene to obtain cumene and oligomerization of light olefins to liquid fuels in the case of beta, observing in all cases improved catalytic activity and product selectivity towards target products when compared to related catalysts. This work has been supported by the Spanish Government-MINECO through "Severo Ochoa" (SEV 2012-0267), MAT2015-71261-R and CTQ2015-70126-R, by the European Union through ERC-AdG-2014-671093 (SynCatMatch) and by the Fundacion Ramon Areces through a research contract of the "Life and Materials Science" program. E. M. G. and M. R. D-R. acknowledge "La Caixa - Severo Ochoa" International PhD Fellowships (call 2015). M. E. M-A. thanks MINECO for economical support through pre-doctoral fellowship (BES-2013-066800). The Electron Microscopy Service of the UPV is acknowledged for their help in sample characterization. Gallego-Sánchez, EM.; Paris-Carrizo, CG.; Díaz-Rey, MDR.; Martínez Armero, ME.; Martínez-Triguero, J.; Martínez, C.; Moliner Marin, M... (2017). Simple organic structure directing agents for synthesizing nanocrystalline zeolites. Chemical Science. 8(12):8138-8149. https://doi.org/10.1039/c7sc02858j Davis, M. E. (2013). Zeolites from a Materials Chemistry Perspective. Chemistry of Materials, 26(1), 239-245. doi:10.1021/cm401914u Moliner,