Conversion of methanol to olefins: Stabilization of nanosized SAPO-34 by hydrothermal treatment

Nano-SAPO-34 zeolite catalyst (20 nm crystal size) has been stabilized by hydrothermal treatment. After steamed at high temperatures (T >= 550 degrees C), its textural properties and high lifetime during the reaction of methanol to olefins (MTO) are preserved, despite the decrease in acidity, even after months of contact with moisture. The stabilization effect is attributed to the migration of silicon to larger silicon islands in which the contribution of silicon on the edge is lower after steaming. Stabilization is not successful by a thermal treatment in air in the absence of water. Steaming at temperature >400 degrees C is required for achieving hydrothermal stabilization. A stability test for SAPO-34 in MTO reaction is proposed. (C) 2015 Elsevier Inc. All rights reserved.Financial support by the Spanish MINECO (Consolider Ingenio 2010-MULTICAT CSD2009-00050, MAT2012-37160, CTQ2012-37925-C03-1, Severo Ochoa SEV-2012-0267), and Generalitat Valenciana by the PROMETEO program (PROMETEOII/2013/011) is acknowledged. Z. Li acknowledges China Scholarship Council (CSC) for a fellowship. J. Yu thanks the Major International Joint Research Project of China for financial supports (Grant No. 21320102001). Support from Servicio de Microscopia Electronica (UPV) is also acknowledged.Li, Z.; Martínez Triguero, LJ.; Yu, J.; Corma Canós, A. (2015). Conversion of methanol to olefins: Stabilization of nanosized SAPO-34 by hydrothermal treatment. Journal of Catalysis. 329:379-388. https://doi.org/10.1016/j.jcat.2015.05.025S37938832

Direct synthesis of the aluminosilicate form of the small pore CDO zeolite with novel OSDAs and the expanded polymorphs

[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.2017.03.014S14715724

Hydrothermal stability and catalytic performance of desilicated highly siliceous zeolites ZSM-5

Highly siliceous zeolites, namely MFI type have attracted the great attention due to their higher hydrothermal stability, higher selectivity to organic compounds, and often better catalytic properties in comparison with Al-rich zeolites. The native zeolite (Si/Al = 164) and its desilicated analogues were deeply characterized with regard to their structural and textural properties by X-ray diffraction, low temperature adsorption of nitrogen and solid-state Al-27 MAS NMR. Their acidic properties were evaluated in quantitative IR studies. Finally, the catalytic performance of desilicated zeolites ZSM-5 was evaluated in the cracking of n-decane, 1,3,5-tri-iso-propylbenzene and vacuum gas oil. In this article, it is shown that high silica zeolites prepared by NaOH and NaOH&TBAOH leaching presented good hydrothermal stability with only slightly lower resistance when comparing to native steamed zeolite. The mesoporosity was preserved after the steaming treatment. The influence of the generated mesoporosity on the higher activity was evidenced in both 1,3,5-tri-isopropylbenzene and diesel oil cracking of steamed hierarchical zeolites. In spite of their lowered acidity, the mesopores system benefited the diffusion of the bulky molecule and finally provided higher activity of hierarchical zeolites. (C) 2016 Elsevier Inc. All rights reserved.This work was financed by Grant No. 2015/18/E/ST4/00191 from the National Science Centre - Poland. F. Rey and J. Martinez-Triguero thank for the support of the Spanish Government-MINECO through "Severo Ochoa" (SEV 2012-0267), MAT2015-71842-P and CTQ2015-68951-C3-1-R.Tarach, KA.; Martínez-Triguero, J.; Rey Garcia, F.; Góra-Marek, K. (2016). Hydrothermal stability and catalytic performance of desilicated highly siliceous zeolites ZSM-5. Journal of Catalysis. 339:256-259. https://doi.org/10.1016/j.jcat.2016.04.023S25625933

Improving the catalytic performance of SAPO-18 for the methanol-to-olefins (MTO) reaction by controlling the Si distribution and crystal size

[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 ERC-AdG-2014-671093 (SynCatMatch); and by the Generalitat Valenciana through the Prometeo program (PROMETEOII/2013/011) is acknowledged.Martínez Franco, R.; Li, Z.; Martínez Triguero, LJ.; Moliner Marin, M.; Corma Canós, A. (2016). Improving the catalytic performance of SAPO-18 for the methanol-to-olefins (MTO) reaction by controlling the Si distribution and crystal size. Catalysis Science and Technology. 6(8):2796-2806. https://doi.org/10.1039/C5CY02298CS2796280668Chen, D., Moljord, K., & Holmen, A. (2012). A methanol to olefins review: Diffusion, coke formation and deactivation on SAPO type catalysts. Microporous and Mesoporous Materials, 164, 239-250. doi:10.1016/j.micromeso.2012.06.046Tian, P., Wei, Y., Ye, M., & Liu, Z. (2015). Methanol to Olefins (MTO): From Fundamentals to Commercialization. ACS Catalysis, 5(3), 1922-1938. doi:10.1021/acscatal.5b00007Moliner, M., Martínez, C., & Corma, A. (2013). Synthesis Strategies for Preparing Useful Small Pore Zeolites and Zeotypes for Gas Separations and Catalysis. Chemistry of Materials, 26(1), 246-258. doi:10.1021/cm4015095Lok, B. M., Messina, C. A., Patton, R. L., Gajek, R. T., Cannan, T. R., & Flanigen, E. M. (1984). Silicoaluminophosphate molecular sieves: another new class of microporous crystalline inorganic solids. Journal of the American Chemical Society, 106(20), 6092-6093. doi:10.1021/ja00332a063Chen, J. Q., Bozzano, A., Glover, B., Fuglerud, T., & Kvisle, S. (2005). Recent advancements in ethylene and propylene production using the UOP/Hydro MTO process. 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Kinetic Modeling of the Methanol-to-Olefins Process on a Silicoaluminophosphate (SAPO-18) Catalyst by Considering Deactivation and the Formation of Individual Olefins. Industrial & Engineering Chemistry Research, 46(7), 1981-1989. doi:10.1021/ie061278oChen, J., Li, J., Wei, Y., Yuan, C., Li, B., Xu, S., … Liu, Z. (2014). Spatial confinement effects of cage-type SAPO molecular sieves on product distribution and coke formation in methanol-to-olefin reaction. Catalysis Communications, 46, 36-40. doi:10.1016/j.catcom.2013.11.016Álvaro-Muñoz, T., Márquez-Álvarez, C., & Sastre, E. (2015). Mesopore-Modified SAPO-18 with Potential Use as Catalyst for the MTO Reaction. Topics in Catalysis, 59(2-4), 278-291. doi:10.1007/s11244-015-0447-0Chen, J., Wright, P. A., Thomas, J. M., Natarajan, S., Marchese, L., Bradley, S. M., … Gai-Boyes, P. L. (1994). SAPO-18 Catalysts and Their Broensted Acid Sites. The Journal of Physical Chemistry, 98(40), 10216-10224. doi:10.1021/j100091a042Bhawe, Y., Moliner-Marin, M., Lunn, J. D., Liu, Y., Malek, A., & Davis, M. (2012). Effect of Cage Size on the Selective Conversion of Methanol to Light Olefins. ACS Catalysis, 2(12), 2490-2495. doi:10.1021/cs300558xDusselier, M., Deimund, M. A., Schmidt, J. E., & Davis, M. E. (2015). Methanol-to-Olefins Catalysis with Hydrothermally Treated Zeolite SSZ-39. ACS Catalysis, 5(10), 6078-6085. doi:10.1021/acscatal.5b01577Martín, N., Li, Z., Martínez-Triguero, J., Yu, J., Moliner, M., & Corma, A. (2016). Nanocrystalline SSZ-39 zeolite as an efficient catalyst for the methanol-to-olefin (MTO) process. Chemical Communications, 52(36), 6072-6075. doi:10.1039/c5cc09719cChen, J., Thomas, J. M., Wright, P. A., & Townsend, R. P. (1994). Silicoaluminophosphate number eighteen (SAPO-18): a new microporous solid acid catalyst. Catalysis Letters, 28(2-4), 241-248. doi:10.1007/bf00806053Hunger, M., Seiler, M., & Buchholz, A. (2001). Catalysis Letters, 74(1/2), 61-68. doi:10.1023/a:1016687014695Fan, D., Tian, P., Xu, S., Xia, Q., Su, X., Zhang, L., … Liu, Z. (2012). A novel solvothermal approach to synthesize SAPO molecular sieves using organic amines as the solvent and template. Journal of Materials Chemistry, 22(14), 6568. doi:10.1039/c2jm15281aAbdollahi, S., Ghavipour, M., Nazari, M., Behbahani, R. M., & Moradi, G. R. (2015). Effects of static and stirring aging on physiochemical properties of SAPO-18 and its performance in MTO process. Journal of Natural Gas Science and Engineering, 22, 245-251. doi:10.1016/j.jngse.2014.11.036Yuen, L.-T., Zones, S. I., Harris, T. V., Gallegos, E. J., & Auroux, A. (1994). Product selectivity in methanol to hydrocarbon conversion for isostructural compositions of AFI and CHA molecular sieves. Microporous Materials, 2(2), 105-117. doi:10.1016/0927-6513(93)e0039-jBleken, F., Bjørgen, M., Palumbo, L., Bordiga, S., Svelle, S., Lillerud, K.-P., & Olsbye, U. (2009). 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Influence of the synthesis method on the catalytic activity of mayenite for the oxidation of gas-phase trichloroethylene

[EN] Catalytic oxidation of trichloroethylene (TCE) in heterogeneous phase (gas-solid) is an effective strategy for the conversion of this pollutant in less harmful compounds, namely CO2, CO and HCl. In this work, we have studied the use of mayenite, a cost-effective material, as an active catalyst for the TCE conversion. In particular, we have assessed the influence of the mayenite synthesis method (hydrothermal, sol-gel and ceramic) on the reaction performance. The materials have been characterized by different techniques, such as XRD, N-2-sorption (BET), TPR, Raman spectroscopy, FESEM-EDX and TEM. The analysis of the light-off curves and product distribution, has shown that the use of the hydrothermal method for the mayenite synthesis results in the most active and selective catalyst. This has been related with a higher surface area and with a higher concentration of oxygen anions in the mayenite prepared by this method. It has been found that the presence of water in the stream do not influence the catalytic performance of the material. A mechanism for the reaction and for the partial deactivation of the catalyst has been proposed.This work was supported by the grants ORSA167988 and ORSA174250 funded by the University of Salerno. AI gratefully acknowledges the Erasmus+ traineeship program. AEP and JMT thanks the Spanish Ministry of Economy and Competitiveness and the Fondo Europeo de Desarrollo Regional through MAT2015-71842-P and CTQ2015-68951-C3-1-R (MINECO/FEDER)Intiso, A.; Martínez-Triguero, J.; Cucciniello, R.; Rossi, F.; Palomares Gimeno, AE. (2019). Influence of the synthesis method on the catalytic activity of mayenite for the oxidation of gas-phase trichloroethylene. Scientific Reports. 9:1-9. https://doi.org/10.1038/s41598-018-36708-2S199Greene, H. L., Prakash, D. S. & Athota, K. V. Combined sorbent/catalyst media for destruction of halogenated VOCs. Appl. Catal. 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Use of Zea mays L. in phytoremediation of trichloroethylene. Environ. Sci. Pollut. Res. 24, 11053–11060 (2017).Costanza, J., Mulholland, J. & Pennell, K. Effects of Thermal Treatments on the Chemical Reactivity of Trichloroethylene (2007).Aranzabal, A. et al. State of the art in catalytic oxidation of chlorinated volatile organic compounds. Chem. Pap. 68, 1169–1186 (2014).Blanch-Raga, N. et al. Catalytic abatement of trichloroethylene over Mo and/or W-based bronzes. Appl. Catal. B Environ. 130, 36–43 (2013).Blanch-Raga, N., Palomares, A. E., Martínez-Triguero, J., Fetter, G. & Bosch, P. Cu mixed oxides based on hydrotalcite-like compounds for the oxidation of trichloroethylene. Ind. Eng. Chem. Res. 52, 15772–15779 (2013).Romero-Sáez, M., Divakar, D., Aranzabal, A., González-Velasco, J. R. & González-Marcos, J. A. Catalytic oxidation of trichloroethylene over Fe-ZSM-5: Influence of the preparation method on the iron species and the catalytic behavior. Appl. Catal. 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Synthesis of higher surface area mayenite by hydrothermal method. Mater. Res. Bull. 46, 1307–1310 (2011).Ude, S. N. et al. High temperature X-ray studies of mayenite synthesized using the citrate sol–gel method. Ceram. Int. 40, 1117–1123 (2014).Blanch-Raga, N. et al. The oxidation of trichloroethylene over different mixed oxides derived from hydrotalcites. Appl. Catal. B Environ. 160, 129–134 (2014).Monshi, A., Foroughi, M. R. & Monshi, M. R. Modified Scherrer Equation to Estimate More Accurately Nano-Crystallite Size Using XRD. World J. Nano Sci. Eng. 02, 154 (2012).Ruszak, M., Witkowski, S. & Sojka, Z. EPR and Raman investigations into anionic redox chemistry of nanoporous 12CaO·7Al2O3 interacting with O2, H2 and N2O. Res. Chem. Intermed. 33, 689–703 (2007).Cucciniello, R., Proto, A., Rossi, F. & Motta, O. Mayenite based supports for atmospheric NOx sampling. Atmos. Environ. 79, 666–671 (2013).Teusner, M. et al. Oxygen Diffusion in Mayenite. J. Phys. Chem. 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Methanol to olefins: activity and stability of nanosized SAPO-34 molecular sieves and control of selectivity by silicon distribution

[EN] Nano-SAPO-34 molecular sieves synthesized in a microwave environment with 20 nm crystal size showed a longer lifetime than SAPO-34 prepared by the conventional hydrothermal method in the reaction of methanol to olefins. It has been found that silicon distribution strongly affects the lifetime and selectivity. Thus, silicon at the border of the silicon islands gives a higher lifetime and lower C2/C3 ratio. This change in activity and selectivity is better explained in terms of different silicon distribution than by preferential diffusion of ethene through the 8MR pores and agrees with transition-state selectivity. The effects of equilibrium of olefins and deactivation by coke were isolated, showing that after full formation of the hydrocarbon pool, selectivity is independent of deactivation by coke.Financial support by the Spanish MINECO (MAT2012-37160, CSD2009-00050-CONSOLIDER/INGENIO 2010), and Generalitat Valenciana by the PROMETEO program is acknowledged. Z. Li acknowledges China Scholarship Council (CSC) for a fellowship. J. Yu thanks the support by the State Basic Research Project of China (Grant no. 2011CB808703) and the National Natural Science Foundation of China.Li, Z.; Martínez Triguero, LJ.; Concepción Heydorn, P.; Yu, J.; Corma Canós, A. (2013). Methanol to olefins: activity and stability of nanosized SAPO-34 molecular sieves and control of selectivity by silicon distribution. Physical Chemistry Chemical Physics. 15(35):14670-14680. https://doi.org/10.1039/c3cp52247dS14670146801535Bjørgen, M., Joensen, F., Spangsberg Holm, M., Olsbye, U., Lillerud, K.-P., & Svelle, S. (2008). Methanol to gasoline over zeolite H-ZSM-5: Improved catalyst performance by treatment with NaOH. Applied Catalysis A: General, 345(1), 43-50. doi:10.1016/j.apcata.2008.04.020Vennestrøm, P. N. R., Grill, M., Kustova, M., Egeblad, K., Lundegaard, L. F., Joensen, F., … Beato, P. (2011). 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A Novel Synthetic Route to Prepare High Surface Area Mayenite Catalyst for TCE Oxidation

[EN] Mayenite (Ca12Al14O33) was synthesized by a novel route based on the use of polymethyl methacrylate (PMMA) as a soft templating agent. The material was tested for the total oxidation of trichloroethylene in the gas phase and the catalytic performance was analysed when using different initial amounts of PMMA in the catalyst synthesis. The results were compared with those obtained with a mayenite synthetized by a classical hydrothermal method. The highest activity in terms of TCE conversion was achieved in the presence of mayenite prepared using 10% w/w of PMMA; its activity was also higher than that of the hydrothermal mayenite. The surface area and the number of superoxide anions (O-2(-)) seem to be the main properties determining the catalytic activity of the material.This research was funded by University of Salerno, grant number ORSA167988 and ORSA174250.Intiso, A.; Martínez-Triguero, J.; Cucciniello, R.; Proto, A.; Palomares Gimeno, AE.; Rossi, F. (2019). A Novel Synthetic Route to Prepare High Surface Area Mayenite Catalyst for TCE Oxidation. Catalysts. 9(1):1-8. https://doi.org/10.3390/catal9010027S1891Yang, S., Kondo, J. N., Hayashi, K., Hirano, M., Domen, K., & Hosono, H. (2004). Formation and Desorption of Oxygen Species in Nanoporous Crystal 12CaO·7Al2O3. Chemistry of Materials, 16(1), 104-110. doi:10.1021/cm034755rCucciniello, R., Intiso, A., Castiglione, S., Genga, A., Proto, A., & Rossi, F. (2017). Total oxidation of trichloroethylene over mayenite (Ca12Al14O33) catalyst. Applied Catalysis B: Environmental, 204, 167-172. doi:10.1016/j.apcatb.2016.11.03

Synthesis of nano-SSZ-13 and its application in the reaction of methanol to olefins

[EN] Nanosized SSZ-13 has been obtained from a one-pot synthesis procedure with the addition of CTAB to the synthesis precursor solution. Nano-SSZ-13 zeolite showed high intracrystalline mesoporosity and compared to standard SSZ-13 presented a much longer lifetime and higher conversion capacity for the reaction of methanol to olefins. The improved properties were attributed to a more efficient utilization of micropores by easier diffusion of reactants and products and slower deactivation by coke. A higher C2/C3 ratio was found for nano-SSZ-13, pointing to a lower deactivation of the aromatics cycle of the hydrocarbon pool.Financial support by the Spanish Government-MINECO through “Severo Ochoa” (SEV 2012-0267), CTQ2015-67592-P, CTQ2015-70126-R, CTQ2015-68951-C3-1-R, MAT2015-71842-P, by the European Union ERC-AdG-2014-671093-SynCatMatch and by the Generalitat Valenciana PROMETEOII/2013/011 is acknowledged. Z. Li acknowledges China Scholarship Council (CSC) for a fellowship. J. Yu thanks the Major International Joint Research Project of China for financial support (Grant No. 21320102001).Li, Z.; Navarro Villalba, MT.; Martínez Triguero, LJ.; Yu, J.; Corma Canós, A. (2016). Synthesis of nano-SSZ-13 and its application in the reaction of methanol to olefins. Catalysis Science and Technology. 6(15):5856-5863. https://doi.org/10.1039/C6CY00433DS5856586361

Synthesis of Al-MTW with low Si/Al ratios by combining organic and inorganic structure directing agents

[EN] A rationalized combination of alkali cations and bulky dicationic organic structure directing agents (OSDAs) has allowed the synthesis of the Al-rich MTW zeolites with Si/Al ratios of similar to 12 and large pore accessibility. Al-27 MAS NMR spectroscopy indicates that most of the aluminum atoms are in tetrahedral coordination in framework positions, and in situ infrared pyridine adsorption/desorption spectroscopy reveals strong Bronsted acidity after cationic exchange for the Al-rich MTW. In addition, another MTW material with a Si/Al ratio of 30 has been synthesized under alkali-free conditions using a bulky dicationic molecule such as OSDA, the lowest Si/Al ratio being achieved for a MTW zeolite synthesized in the absence of alkali-cations in the synthesis media. The catalytic activity of these MTW materials has been tested for the n-decane cracking reaction, achieving higher catalytic activities and olefin yields than other related large pore zeolites.Financial support from the Spanish Government-MINECO through "Severo Ochoa" (SEV 2012-0267), Consolider Ingenio 2010-Multicat and, MAT2012-37160 is acknowledged.Paris-Carrizo, CG.; Martín-García, N.; Martínez-Triguero, J.; Moliner Marin, M.; Corma Canós, A. (2016). Synthesis of Al-MTW with low Si/Al ratios by combining organic and inorganic structure directing agents. New Journal of Chemistry. 40(5):4140-4145. https://doi.org/10.1039/C5NJ01203AS41404145405LaPierre, R. B., Rohrman, A. C., Schlenker, J. L., Wood, J. D., Rubin, M. K., & Rohrbaugh, W. J. (1985). The framework topology of ZSM-12: A high-silica zeolite. Zeolites, 5(6), 346-348. doi:10.1016/0144-2449(85)90121-6Gies, H., & Marker, B. (1992). 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Journal of Catalysis, 217(2), 298-309. doi:10.1016/s0021-9517(03)00071-xPerego, C., Amarilli, S., Millini, R., Bellussi, G., Girotti, G., & Terzoni, G. (1996). Experimental and computational study of beta, ZSM-12, Y, mordenite and ERB-1 in cumene synthesis. Microporous Materials, 6(5-6), 395-404. doi:10.1016/0927-6513(96)00037-5Jones, C. (1999). m-Xylene reactions over zeolites with unidimensional pore systems. Applied Catalysis A: General, 181(2), 289-303. doi:10.1016/s0926-860x(98)00401-3Zhang, W., & Smirniotis, P. G. (1999). Catalysis Letters, 60(4), 223-228. doi:10.1023/a:1019079612655Katovic, A., Chiche, B. H., Di Renzo, F., Giordano, G., & Fajula, F. (2000). Influence of the aluminium content on the acidity and catalytic activity of MTW-type zeolites. 12th International Congress on Catalysis, Proceedings of the 12th ICC, 857-862. doi:10.1016/s0167-2991(00)81066-6Kamimura, Y., Itabashi, K., & Okubo, T. (2012). 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Hierarchical zeolites TNU-9 and IM-5 as the catalysts for cracking processes

[EN] The 10-ring zeolites TNU-9 and IM-5 were obtained by a desilication and evaluated in series of acid-catalysed cracking reactions. n-Decane and 1,3,5-tri-iso-propylbenzene cracking were performed as model reactions, while vacuum gas oil, polypropylene and polyethylene were cracked into add-value lower molecular weight chemicals. The catalytic performance improvement of hierarchical zeolites was rationalized by deep acid sites characterization in situ FT-IR studies of pyridine, carbon monoxide and 2,6-di-tert-butylpyridine sorption. Further, operando FT-IR-GC studies supported by 2D COS (two-dimensional correlation) analysis provided insight into cracking and coking of catalysts during polypropylene and polyethylene decomposition. It was found that NaOH-derived catalysts ensure the most upsurged acidity, in terms of number and accessibility of the sites, and then with better performance. In VGO cracking the connected mesopores added post-synthesis increased yields to propylene and middle distillates and lowered coke production. A bigger share of iso-olefins was observed both in VGO and polyolefins cracking products.KGM acknowledges the Grant No 2021/43/B/ST4/00307 form National Science Center, Poland. KAT acknowledges the Grant No 2020/37/B/ST4/01215 form National Science Center, Poland. For the purpose of Open Access, the author has applied a CC-BY public copyright licence to any Author Accepted Manuscript (AAM) version arising from this submission. JMT acknowledges the Grant MFA/2022/016 from Advanced Materials program supported by MCIN with funding from European Union NextGenerationEU (PRTR-C17. I1) and by Generalitat Valenciana. The study was carried out using research infrastructure purchased with the funds of the European Union in the framework of the Smart Growth Operational Program, Measure 4.2; Grant No. POIR.04.02.00-00-D001/20-00, "ATOMIN 2.0-ATOMic scale science for the INnovative economy". The open-access publication of this article has been supported by a grant from the Faculty of Chemistry under the Strategic Programme Excellence Initiative at Jagiellonian University.Tarach, KA.; Martínez-Triguero, J.; Valencia Valencia, S.; Wojciechowska, K.; Rey Garcia, F.; Góra-Marek, K. (2023). Hierarchical zeolites TNU-9 and IM-5 as the catalysts for cracking processes. Applied Catalysis B Environmental. 338. https://doi.org/10.1016/j.apcatb.2023.12306633