Suchergebnisse

A multi-dimensional extra-large pore silicogermanate zeolite, named ITQ-54, has been synthesised by in situ decomposition of the N,N-dicyclohexylisoindolinium cation into the N-cyclohexylisoindolinium cation. Its structure was solved by 3D rotation electron diffraction (RED) from crystals of ca. 1 μm in size. The structure of ITQ-54 contains straight intersecting 20 × 14 × 12-ring channels along the three crystallographic axes and it is one of the few zeolites with extra-large channels in more than one direction. ITQ-54 has a framework density of 11.1 T atoms per 1000 Å3, which is one of the lowest among the known zeolites. ITQ-54 was obtained together with GeO2 as an impurity. A heavy liquid separation method was developed and successfully applied to remove this impurity from the zeolite. ITQ-54 is stable up to 600 °C and exhibits permanent porosity. The structure was further refined using powder X-ray diffraction (PXRD) data for both as-made and calcined samples. ; This work was supported by the Spanish Government (MAT2012-38567-C02-01, Consolider Ingenio 2010-Multicat CSD-2009-00050 and Severo Ochoa SEV-2012-0267), Generalitat Valenciana (Project Prometeo), the Swedish Research Council (VR), the Swedish Governmental Agency for Innovation Systems (VINNOVA) and the Knut & Alice Wallenberg Foundation through a grant for purchasing the TEMs and the project grant 3DEM-NATUR. Y. F. Yun thanks the China Scholarship Council (CSC). The authors acknowledge ESRF, Grenoble for the use of the beamline ID31 and the mail-in system of 11-BM at the Advanced Photon Source, Argonne National Laboratory, USA. ; Jiang, J.; Yun, Y.; Zou, X.; Jorda Moret, JL.; Corma Canós, A. (2015). ITQ-54: a multi-dimensional extra-large pore zeolite with 20 × 14 × 12-ring channels. Chemical Science. 6(1):480-485. https://doi.org/10.1039/c4sc02577f ; S ; 480 ; 485 ; 6 ; 1 ; Davis, M. E. (2002). Ordered porous materials for emerging applications. Nature, 417(6891), 813-821. doi:10.1038/nature00785 ; Atienzar, P., Díaz-Cabañas, M. J., Moliner, ...

The synthesis of crystalline microporous materials containing large pores is in high demand by industry, especially for the use of these materials as catalysts in chemical processes involving bulky molecules. An extra-large-pore silicoaluminophosphate with 16-ring openings, ITQ-51, has been synthesized by the use of bulky aromatic proton sponges as organic structure-directing agents. Proton sponges show exceptional properties for directing extra-large zeolites because of their unusually high basicity combined with their large size and rigidity. This extra-large-pore material is stable after calcination, being one of the very few examples of hydrothermally stable molecular sieves containing extra-large pores. The structure of ITQ-51 was solved from submicrometer-sized crystals using the rotation electron diffraction method. Finally, several hypothetical zeolites related to ITQ-51 have been proposed. ; The authors gratefully acknowledge Dr. Alejandro Vidal-Moya for the SUP>27 /SUP>Al MQ MAS NMR experiment. The authors also acknowledge financial support from Ministerio de Economia y Competitividad of Spain (MAT2012-37160), Consolider Ingenio 2010-MULTICAT, Generalitat Valenciana through the PROMETEO program, Universitat Politecnica de Valencia through PAID-06-11 (n.1952), the Swedish Research Council (VR), the Swedish Governmental Agency for Innovation Systems (VINNOVA), and the Goran Gustafsson Foundation. M. M. also acknowledges "Subprograma Ramon y Cajal" for Contract RYC-2011-08972. The TEM used in this study was purchased from a grant by the Knut and Alice Wallenberg Foundation. ; Martínez Franco, R.; Moliner Marin, M.; Yun, Y.; Sun, J.; Wan, W.; Zou, X.; Corma Canós, A. (2013). Synthesis of an extra-large molecular sieve using proton sponges as organic structure-directing agents. Proceedings of the National Academy of Sciences. 110(10):3749-3754. https://doi.org/10.1073/pnas.1220733110 ; S ; 3749 ; 3754 ; 110 ; 10

The combination of different experimental techniques, such as solid C-13 and H-1 magic-angle spinning NMR spectroscopy, fluorescence spectroscopy and powder X-ray diffraction, together with theoretical calculations allows the determination of the unique structure directing the role of the bulky aromatic proton sponge 1,8-bis(dimethylamino)naphthalene (DMAN) towards the extra-large-pore ITQ-51 zeolite through supra-molecular assemblies of those organic molecules. ; This work has been supported by the Spanish Government through Consolider Ingenio 2010-Multicat, the 'Severo Ochoa Programme' (SEV 2012-0267), MAT2012-37160; UPV through PAID-06-11 (no. 1952); the Swedish Research Council (VR) and the Swedish Governmental Agency for Innovation Systems (VINNOVA). ; Martínez Franco, R.; Sun, J.; Sastre Navarro, GI.; Yun, Y.; Zou, X.; Moliner Marin, M.; Corma Canós, A. (2014). Supra-molecular assembly of aromatic proton sponges to direct the crystallization of extra-large-pore zeotypes. Proceedings of the Royal Society of London. Series A, Mathematical and physical sciences. 470:1-13. https://doi.org/10.1098/rspa.2014.0107 ; S ; 1 ; 13 ; 470 ; Moliner, M., Rey, F., & Corma, A. (2013). Towards the Rational Design of Efficient Organic Structure-Directing Agents for Zeolite Synthesis. Angewandte Chemie International Edition, 52(52), 13880-13889. doi:10.1002/anie.201304713 ; Freyhardt, C. C., Tsapatsis, M., Lobo, R. F., Balkus, K. J., & Davis, M. E. (1996). A high-silica zeolite with a 14-tetrahedral-atom pore opening. Nature, 381(6580), 295-298. doi:10.1038/381295a0 ; Wagner, P., Yoshikawa, M., Tsuji, K., Davis, M. E., Wagner, P., Lovallo, M., & Taspatsis, M. (1997). CIT-5: a high-silica zeolite with 14-ring pores. Chemical Communications, (22), 2179-2180. doi:10.1039/a704774f ; Burton, A., Elomari, S., Chen, C.-Y., Medrud, R. C., Chan, I. Y., Bull, L. M., … Vittoratos, E. S. (2003). SSZ-53 and SSZ-59: Two Novel Extra-Large Pore Zeolites. Chemistry - A European Journal, 9(23), 5737-5748. ...

[EN] A new germanosilicate zeolite (denoted as ITQ-53) with extra-large pores has been synthesised using tri-tertbutylmethylphosphonium cation as the organic structure directing agent (OSDA). Rotation electron diffraction (RED) was used to identify ITQ-53 from an initially-synthesised sample containing impurities, and to solve its structure. The structure was refined against PXRD data of pure ITQ-53 samples obtained after synthesis optimisation. ITQ-53 is the first example of extra-large pore zeolites with tri-directional interconnected 14 x 14 x 14-ring channels. It is stable up to at least 650 degrees C. The structure of ITQ-53 changes from monoclinic to orthorhombic upon calcination. ; This work was supported by the Spanish Government (MAT2012-38567-C02-01, Consolider Ingenio 2010-Multicat CSD-2009-00050 and Severo Ochoa SEV-2012-0267), the Swedish Research Council (VR), the Swedish Governmental Agency for Innovation Systems (VINNOVA) and the Knut & Alice Wallenberg Foundation through a grant for purchasing the TEMs and the project grant 3DEM-NATUR. Yifeng Yun thanks the China Scholarship Council (CSC). ; Yun, Y.; Hernández Rodríguez, M.; Wan, W.; Zou, X.; Jorda Moret, JL.; Cantin Sanz, A.; Rey Garcia, F. (2015). The first zeolite with a tri-directional extra-large 14-ring pore system derived using a phosphonium-based organic molecule. Chemical Communications. 51(36):7602-7605. https://doi.org/10.1039/c4cc10317c ; S ; 7602 ; 7605 ; 51 ; 36 ; C. Baerlocher and L.McCusker, Database of Zeolite Structures: http://www.iza-structure.org/databases/ ; Estermann, M., McCusker, L. B., Baerlocher, C., Merrouche, A., & Kessler, H. (1991). A synthetic gallophosphate molecular sieve with a 20-tetrahedral-atom pore opening. Nature, 352(6333), 320-323. doi:10.1038/352320a0 ; Su, J., Wang, Y., Lin, J., Liang, J., Sun, J., & Zou, X. (2013). A silicogermanate with 20-ring channels directed by a simple quaternary ammonium cation. Dalton Trans., 42(5), 1360-1363. doi:10.1039/c2dt32231e ; Wei, Y., Tian, Z., Gies, H., ...