Suchergebnisse

The combination of Cu(II) triethylenetetramine and N,N-dimethyl-3,5-dimethylpiperidinium as structure directing agents allowed the direct preparation of highly active and hydrothermally stable Cu-SAPO-18 for the selective catalytic reduction of NOx with NH3. The approach allows performing a one-pot synthesis avoiding intermediate calcination and ion exchange, while achieving complete framework Si isolation. Combination of physicochemical characterization techniques show that copper exists as extra-framework Cu2+, which have been identified as the specific active sites for the SCR of NOx. The selective presence of isolated Si species in the zeolitic framework introduces high hydrothermal stability. ; Financial support by the Spanish Government-MINECO through "Severo Ochoa" (SEV 2012-0267), Consolider Ingenio 2010-Multicat, MAT2012-37160 and, Intramural-2014801015 is acknowledged. The authors thank Isabel Millet for technical support. ; Martínez Franco, R.; Moliner Marin, M.; Corma Canós, A. (2014). Direct synthesis design of Cu-SAPO-18, a very efficient catalyst for the SCR of NOx. Journal of Catalysis. 319:36-43. https://doi.org/10.1016/j.jcat.2014.08.005 ; S ; 36 ; 43 ; 319

The isomorphic substitution of two different metals (Mg and Co) within the framework of the ITQ-51 zeotype (IFO structure) using bulky aromatic proton sponges as organic structure-directing agents (OSDAs) has allowed the synthesis of different stable metal-containing extra-large-pore zeotypes with high pore accessibility and acidity. These metalcontaining extra-large-pore zeolites, named MgITQ-51 and CoITQ-51, have been characterized by different techniques, such as powder X-ray diffraction, scanning electron microscopy, energy dispersive Xray spectrometry, UV-Vis spectroscopy, temperature programmed desorption of ammonia and Fourier transform infrared spectroscopy, to study their physico-chemical properties. The characterization confirms the preferential insertion of Mg and Co atoms within the crystalline structure of the ITQ-51 zeotype, providing high Brønsted acidity, and allowing their use as efficient heterogeneous acid catalysts in industrially relevant reactions involving bulky organic molecules. ; Financial support by the Spanish Government-MINECO through 'Severo Ochoa' (SEV 2012–0267), Consolider Ingenio 2010-Multicat and MAT2012–37160 is acknowledged. The European Union is also acknowledged by the SynCatMatch project (ERC-AdG-2014-671093). ; Peer Reviewed

[EN] The isomorphic substitution of two different metals (Mg and Co) within the framework of the ITQ-51 zeotype (IFO structure) using bulky aromatic proton sponges as organic structure-directing agents (OSDAs) has allowed the synthesis of different stable metal-containing extra-large-pore zeotypes with high pore accessibility and acidity. These metal-containing extra-large-pore zeolites, named MgITQ-51 and CoITQ-51, have been characterized by different techniques, such as powder X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectrometry, UV-Vis spectroscopy, temperature programmed desorption of ammonia and Fourier transform infrared spectroscopy, to study their physico-chemical properties. The characterization confirms the preferential insertion of Mg and Co atoms within the crystalline structure of the ITQ-51 zeotype, providing high Bronsted acidity, and allowing their use as efficient heterogeneous acid catalysts in industrially relevant reactions involving bulky organic molecules. ; Financial support by the Spanish Government-MINECO through 'Severo Ochoa' (SEV 2012-0267), Consolider Ingenio 2010-Multicat and MAT2012-37160 is acknowledged. The European Union is also acknowledged by the SynCatMatch project (ERC-AdG-2014-671093). ; Martínez Franco, R.; Paris-Carrizo, CG.; Moliner Marin, M.; Corma Canós, A. (2016). Synthesis of highly stable metal-containing extra-large-pore molecular sieves. Philosophical Transactions A: Mathematical, Physical and Engineering Sciences. 374(2061). https://doi.org/10.1098/rsta.2015.0075 ; S ; 374 ; 2061 ; Jiang, J., Yu, J., & Corma, A. (2010). Extra-Large-Pore Zeolites: Bridging the Gap between Micro and Mesoporous Structures. Angewandte Chemie International Edition, 49(18), 3120-3145. doi:10.1002/anie.200904016 ; 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 ...

The physico-chemical properties of the small pore SAPO-18 zeotype have been controlled by properly selecting the organic molecules acting as organic structure directing agents (OSDAs). The two organic molecules selected to attempt the synthesis of the SAPO-18 materials were N,N-diisopropylethylamine (DIPEA) and N,N-dimethyl-3,5-dimethylpiperidinium (DMDMP). On the one hand, DIPEA allows small crystal sizes (0.1-0.3 μm) to be attained with limited silicon distributions when the silicon content in the synthesis gel is high (Si/TO ∼0.8). On the other hand, the use of DMDMP directs the formation of larger crystallites (0.9-1.0 μm) with excellent silicon distributions, even when the silicon content in the synthesis media is high (Si/TO ∼0.8). It is worth noting that this is the first description of the use of DMDMP as OSDA for the synthesis of the SAPO-18 material, revealing not only the excellent directing role of this OSDA in stabilizing the large cavities present in the SAPO-18 structure, but also its role in selectively placing the silicon atoms in isolated framework positions. The synthesized SAPO-18 materials have been characterized by different techniques, such as powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), N adsorption, solid state NMR, and ammonia temperature programmed desorption (NH-TPD). Finally, their catalytic activity has been evaluated for the methanol-to-olefin (MTO) process at different reaction temperatures (350 and 400 °C), revealing that the SAPO-18 catalysts with optimized silicon distributions and crystal sizes show excellent catalytic properties for the MTO reaction. These optimized SAPO-18 materials present improved catalyst lifetimes compared to standard SAPO-34 and SSZ-39 catalysts, even when tested at low reaction temperatures (i.e. 350 °C). ; Financial support by the Spanish Government-MINECO through "Severo Ochoa" (SEV 2012-0267), MAT2015-71261-R, and CTQ2015-68951-C3-1-R; by the European Union through ERC-AdG-2014-671093 (SynCatMatch); and by the Generalitat Valenciana through the Prometeo program (PROMETEOII/2013/011) is acknowledged. ; Peer Reviewed

[EN] A general procedure to synthesize the Al-containing layered CDO precursor (PreCDO) is presented, allowing its preparation under broad Si/Al molar ratios by using novel pyrrole-derived organic molecules as organic structure directing agents (OSDAs). The direct calcination of the PreCDO materials results in crystalline Al-containing small-pore CDO zeolites with controlled Al species in tetrahedral coordination. In contrast, mild acid treatments on the PreCDO materials allow achieving medium-pore interlayer expanded CDO zeolites (IEZ-CDO). These expanded zeolites show high crystallinity, high porosity and controlled Si/Al molar ratios. Finally, preliminary catalytic results indicate that the Al-containing CDO and IEZ-CDO samples show good activity and selectivity for the selective catalytic reduction (SCR) of NOx, and methanol-to-olefins (MTO) processes, respectively. (C) 2017 Elsevier Inc. All rights reserved. ; This work has been supported by the Spanish Government-MINECO through "Severo Ochoa" (SEV 2012-0267) and MAT2015-71261-R programs, and by the Fundacion Ramon Areces through a research project in "Life and Materials Sciences" program. The authors thank Isabel Millet for technical support. ; Martínez Franco, R.; Paris, C.; Martínez-Triguero, J.; Moliner Marin, M.; Corma Canós, A. (2017). Direct synthesis of the aluminosilicate form of the small pore CDO zeolite with novel OSDAs and the expanded polymorphs. Microporous and Mesoporous Materials. 246:147-157. https://doi.org/10.1016/j.micromeso.2017.03.014 ; S ; 147 ; 157 ; 246

[EN] The physico-chemical properties of the small pore SAPO-18 zeotype have been controlled by properly selecting the organic molecules acting as organic structure directing agents (OSDAs). The two organic molecules selected to attempt the synthesis of the SAPO-18 materials were N,N-diisopropylethylamine (DIPEA) and N,N-dimethyl-3,5-dimethylpiperidinium (DMDMP). On the one hand, DIPEA allows small crystal sizes (0.1-0.3 mu m) to be attained with limited silicon distributions when the silicon content in the synthesis gel is high (Si/TO2 similar to 0.8). On the other hand, the use of DMDMP directs the formation of larger crystallites (0.9-1.0 mu m) with excellent silicon distributions, even when the silicon content in the synthesis media is high (Si/TO2 similar to 0.8). It is worth noting that this is the first description of the use of DMDMP as OSDA for the synthesis of the SAPO-18 material, revealing not only the excellent directing role of this OSDA in stabilizing the large cavities present in the SAPO-18 structure, but also its role in selectively placing the silicon atoms in isolated framework positions. The synthesized SAPO-18 materials have been characterized by different techniques, such as powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), N-2 adsorption, solid state NMR, and ammonia temperature programmed desorption (NH3-TPD). Finally, their catalytic activity has been evaluated for the methanol-to-olefin (MTO) process at different reaction temperatures (350 and 400 degrees C), revealing that the SAPO-18 catalysts with optimized silicon distributions and crystal sizes show excellent catalytic properties for the MTO reaction. These optimized SAPO-18 materials present improved catalyst lifetimes compared to standard SAPO-34 and SSZ-39 catalysts, even when tested at low reaction temperatures (i.e. 350 degrees C). ; Financial support by the Spanish Government-MINECO through "Severo Ochoa" (SEV 2012-0267), MAT2015-71261-R, and CTQ2015-68951-C3-1-R; by the European Union through ...

This paper focuses on the design of an innovative air-conditioning system, namely a magnetocaloric air-conditioner for an electric minibus. An integrated design of the complete system is necessary, as the hot and cold side of the regenerator will work under dynamic conditions which depend on the instantaneous thermal load in the cabin. In order to assist the design of the system, a dynamic model has been developed for the cabin, the hydraulic loops and heat exchangers, and the magnetocaloric unit. This paper presents (i) a description of the dynamic models, (ii) an analysis of the operating conditions of the magnetocaloric unit and (iii) a discussion on the design of the magnetocaloric air-conditioner. The results show that the electric minibus requests 1.60 kW of cooling power over a span of 37 K in cooling mode, and 3.39 kW of heating power over a span of 40 K. ; This work has been supported by Haldor-Topsoe, the Spanish Government through Consolider Ingenio 2010-Multicat, the "Severo Ochoa Program", and MAT2012-37160. Manuel Moliner also acknowledges to "Subprograma Ramon y Cajal" for the contract RYC-2011-08972. The authors thank Isabel Millet for technical support. ; Martínez Franco, R.; Moliner Marin, M.; Concepción Heydorn, P.; Thogersen, JR.; Corma Canós, A. (2014). Synthesis, characterization and reactivity of high hydrothermally stable Cu-SAPO-34 materials prepared by one-pot processes. Journal of Catalysis. 314:73-82. https://doi.org/10.1016/j.jcat.2014.03.018 ; S ; 73 ; 82 ; 314

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

Light alkenes oligomerization, performed in the presence of heterogeneous acid catalysts, is an interesting alternative for the production of clean liquid fuels. The process, when catalyzed by zeolites, is flexible and can be directed to the formation of oligomers in the gasoline, jet fuel, or diesel range by adjusting the reaction conditions and the zeolite's structure. Herein we show how reducing the crystal size of large-pore Beta zeolites down to 10–15 nm and controlling the number and strength distribution of their Brønsted acid sites leads to highly active and stable catalysts, selective to true oligomers within the naphtha and, especially, the diesel range. The shorter diffusion path lengths in the smaller crystallites and the reduced Brønsted acid site density of the two nanosized beta zeolites (10–15 nm) synthesized with Si/Al = 15 lead to 1-pentene conversion above 80% during the 6 h time on stream (TOS) at a space time (W/F) of 2.8 g·h·mol–1. This value is higher than the olefin conversion obtained for a commercial nanobeta (30 nm) at a 3-fold space time of 9.1 g·h·mol–1. ; Financial support by the Spanish Government-MINECO through "Severo Ochoa" (SEV-2016-0683), MAT2015-71261-R and CTQ2015-70126-R, by the Fundacion Ramón Areces through a research project within the "Life and Materials Sciences" program, and by the European Union through ERCAdG-2014-671093−Syn-CatMatch is acknowledged. M.R.D-R. acknowledges "La Caixa−Severo Ochoa" International PhD Fellowships (call 2015). ; Peer Reviewed

An efficient synthesis methodology to obtain homogeneous nanosized high-silica Beta zeolites (∼10-20 nm) with high solid yields (above 95%) using simple alkyl-substituted flexible dicationic OSDAs is described. These dicationic OSDAs allow the synthesis of nanosized Beta zeolites with different Si/Al ratios (15-30) in alkaline and fluoride media, resulting in nanocrystalline materials with different physico-chemical properties. These nanosized Beta zeolites show better catalytic behavior towards the industrially-relevant alkylation of benzene with propylene to obtain cumene compared with other commercially available nanosized Beta zeolites. ; Financial support from the Spanish Government-MINECO through "Severo Ochoa" (SEV 2012-0267), Consolider Ingenio 2010-Multicat, MAT2012-37160 and, MAT2012-31657 is acknowledged. The European Union is also acknowledged by the SynCatMatch project (ERC-AdG-2014-671093). M.E.M-A. thanks MINECO for economical support through a pre-doctoral fellowship (BES-2013-066800). ; Peer Reviewed

[EN] An efficient synthesis methodology to obtain homogeneous nanosized high-silica Beta zeolites ( 10¿20 nm) with high solid yields (above 95%) using simple alkyl-substituted flexible dicationic OSDAs is described. These dicationic OSDAs allow the synthesis of nanosized Beta zeolites with different Si/Al ratios (15¿30) in alkaline and fluoride media, resulting in nanocrystalline materials with different physicochemical properties. These nanosized Beta zeolites show better catalytic behavior towards the industrially-relevant alkylation of benzene with propylene to obtain cumene compared with other commercially available nanosized Beta zeolites. ; Financial support from the Spanish Government-MINECO through "Severo Ochoa" (SEV 2012-0267), Consolider Ingenio 2010-Multicat, MAT2012-37160 and, MAT2012-31657 is acknowledged. The European Union is also acknowledged by the SynCatMatch project (ERC-AdG-2014-671093). M.E.M-A. thanks MINECO for economical support through a pre-doctoral fellowship (BES-2013-066800). ; Martínez Franco, R.; Paris-Carrizo, CG.; Martínez Armero, ME.; Martínez, C.; Moliner Marin, M.; Corma Canós, A. (2015). High-silica nanocrystalline Beta zeolites: efficient synthesis and catalytic application. Chemical Science. 7(1):102-108. https://doi.org/10.1039/c5sc03019f ; S ; 102 ; 108 ; 7 ; 1

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] Light alkenes oligomerization, performed in the presence of heterogeneous acid catalysts, is an interesting alternative for the production of clean liquid fuels. The process, when catalyzed by zeolites, is flexible and can be directed to the formation of oligomers in the gasoline, jet fuel, or diesel range by adjusting the reaction conditions and the zeolite's structure. Herein we show how reducing the crystal size of large-pore Beta zeolites down to 10-15 nm and controlling the number and strength distribution of their Bronsted acid sites leads to highly active and stable catalysts, selective to true oligomers within the naphtha and, especially, the diesel range. The shorter diffusion path lengths in the smaller crystallites and the reduced Bronsted acid site density of the two nanosized beta zeolites (10-15 nm) synthesized with Si/Al = 15 lead to 1-pentene conversion above 80% during the 6 h time on stream (TOS) at a space time (W/F) of 2.8 g.h.mol(-1). This value is higher than the olefin conversion obtained for a commercial nanobeta (30 nm) at a 3-fold space time of 9.1 g.h.mol(-1). ; Financial support by the Spanish Government-MINECO through "Severn Ochoa" (SEV-2016-0683), MAT2015-71261-R and CTQ2015-70126-R, by the Fundacion Ramon Areces through a research project within the "Life and Materials Sciences" program, and by the European Union through ERC-AdG-2014-671093-Syn-CatMatch is acknowledged. M.R.D-R. acknowledges "La Caixa-Severo Ochoa" International PhD Fellowships (call 2015). The Electron Microscopy Service of the Universitat Politecnica de Valencia is acknowledged for their help in sample characterization. ; Díaz-Rey, MDR.; Paris-Carrizo, CG.; Martínez Franco, R.; Moliner Marin, M.; Martínez, C.; Corma Canós, A. (2017). Efficient Oligomerization of Pentene into Liquid Fuels on Nanocrystalline Beta Zeolites. ACS Catalysis. 7(9):6170-6178. https://doi.org/10.1021/acscatal.7b00817 ; S ; 6170 ; 6178 ; 7 ; 9