Organic-Free Synthesis of Zeolite Y with High Si/Al Ratios: Combined Strategy of In Situ Hydroxyl Radical Assistance and Post-Synthesis Treatment

[EN] Zeolite Y, with a high SiO2/Al(2)O(3)ratio (SAR), plays an important role in fluidized catalytic cracking processes. However, in situ synthesis of zeolite Y with high SARs remains a challenge because of kinetic limitations. Here, zeolite Y with an SAR of 6.35 is synthesized by a hydroxyl radical assisted route. Density-functional theory (DFT) calculations suggest that hydroxyl radicals preferentially enhanced the formation of Si-O-Si bonds, thus leading to an increased SAR. To further increase the SAR, a dealumination process was carried out using citric acid, with a subsequent second-step hydrothermal crystallization, giving an SAR of up to 7.5 while maintaining good crystallinity and high product yield. The resultant zeolite Y shows good performance in cumene cracking. Introduced here is a new strategy for synthesizing high SAR zeolite Y, which is widely used in commercial applications.We thank the National Natural Science Foundation of China (Grant 21920102005, 21621001 and 21835002), the National Key Research and Development Program of China (Grant 2016YFB0701100), the 111 Project (B17020), and the Spanish Government-MINECO (SEV-2016-0683 and MAT2017-82288-C2-1-P (AEI/FEDER, UE)) for supporting this work. P. F. thanks ITQ for his contract.Wang, J.; Liu, P.; Boronat Zaragoza, M.; Ferri-Vicedo, P.; Xu, Z.; Liu, P.; Shen, B.... (2020). Organic-Free Synthesis of Zeolite Y with High Si/Al Ratios: Combined Strategy of In Situ Hydroxyl Radical Assistance and Post-Synthesis Treatment. Angewandte Chemie International Edition. 59(39):17225-17228. https://doi.org/10.1002/anie.20200571517225172285939Martínez, C., & Corma, A. (2011). Inorganic molecular sieves: Preparation, modification and industrial application in catalytic processes. Coordination Chemistry Reviews, 255(13-14), 1558-1580. doi:10.1016/j.ccr.2011.03.014Li, Y., & Yu, J. (2014). New Stories of Zeolite Structures: Their Descriptions, Determinations, Predictions, and Evaluations. Chemical Reviews, 114(14), 7268-7316. doi:10.1021/cr500010rDusselier, M., & Davis, M. E. (2018). Small-Pore Zeolites: Synthesis and Catalysis. Chemical Reviews, 118(11), 5265-5329. doi:10.1021/acs.chemrev.7b00738Yi, T., Li, J., Zhang, Y., & Yang, X. (2018). A Novel Nano-sized Catalyst CeO2-CuO/Hollow ZSM-5 for NOx Reduction with NH3. Chemical Research in Chinese Universities, 34(4), 661-664. doi:10.1007/s40242-018-7333-9Scherzer, J. (1991). Designing FCC catalysts with high-silica Y zeolites. Applied Catalysis, 75(1), 1-32. doi:10.1016/s0166-9834(00)83119-xNavarro, U. (2002). Impact of Deactivation Conditions on the Acidity of Y Zeolites Used in the Formulation of FCC Catalysts, Studied by FTIR of Adsorbed CO. Journal of Catalysis, 211(1), 64-74. doi:10.1016/s0021-9517(02)93728-0Camblor, M. A., Corma, A., Martínez, A., Mocholí, F. A., & Pariente, J. P. (1989). Catalytic cracking of gasoil. Applied Catalysis, 55(1), 65-74. doi:10.1016/s0166-9834(00)82317-9Williams, B. A., Babitz, S. M., Miller, J. T., Snurr, R. Q., & Kung, H. H. (1999). The roles of acid strength and pore diffusion in the enhanced cracking activity of steamed Y zeolites. Applied Catalysis A: General, 177(2), 161-175. doi:10.1016/s0926-860x(98)00264-6Xu, B., Bordiga, S., Prins, R., & van Bokhoven, J. A. (2007). Effect of framework Si/Al ratio and extra-framework aluminum on the catalytic activity of Y zeolite. Applied Catalysis A: General, 333(2), 245-253. doi:10.1016/j.apcata.2007.09.018Delprato, F., Delmotte, L., Guth, J. L., & Huve, L. (1990). Synthesis of new silica-rich cubic and hexagonal faujasites using crown-etherbased supramolecules as templates. Zeolites, 10(6), 546-552. doi:10.1016/s0144-2449(05)80310-0Dougnier, F., Patarin, J., Guth, J. L., & Anglerot, D. (1992). Synthesis, characterization, and catalytic properties of silica-rich faujasite-type zeolite (FAU) and its hexagonal analog (EMT) prepared by using crown-ethers as templates. Zeolites, 12(2), 160-166. doi:10.1016/0144-2449(92)90078-4He, D., Yuan, D., Song, Z., Tong, Y., Wu, Y., Xu, S., … Liu, Z. (2016). Hydrothermal synthesis of high silica zeolite Y using tetraethylammonium hydroxide as a structure-directing agent. Chemical Communications, 52(86), 12765-12768. doi:10.1039/c6cc06786gZhu, L., Ren, L., Zeng, S., Yang, C., Zhang, H., Meng, X., … Xiao, F.-S. (2013). High temperature synthesis of high silica zeolite Y with good crystallinity in the presence of N-methylpyridinium iodide. Chemical Communications, 49(89), 10495. doi:10.1039/c3cc43974gYuan, D., He, D., Xu, S., Song, Z., Zhang, M., Wei, Y., … Xu, Y. (2015). Imidazolium-based ionic liquids as novel organic SDA to synthesize high-silica Y zeolite. Microporous and Mesoporous Materials, 204, 1-7. doi:10.1016/j.micromeso.2014.10.049P. E.Eberly S. M.Laurent H. E.Robson(Esso Research and Engineering Company) U.S. Patent 3 506 400 1970;P. E.Pickert(Union Carbide Corporation) U.S. Patent 3 640 681 1972;D. A.Young(Union Oil Company of California) U.S. Patent 3 644 200 1972;Kerr, G. T. (1968). Chemistry of crystalline aluminosilicates. V. Preparation of aluminum-deficient faujasites. The Journal of Physical Chemistry, 72(7), 2594-2596. doi:10.1021/j100853a058Qin, Z., Shen, W., Zhou, S., Shen, Y., Li, C., Zeng, P., & Shen, B. (2020). Defect-assisted mesopore formation during Y zeolite dealumination: The types of defect matter. Microporous and Mesoporous Materials, 303, 110248. doi:10.1016/j.micromeso.2020.110248Qin, Z., Cychosz, K. A., Melinte, G., El Siblani, H., Gilson, J.-P., Thommes, M., … Valtchev, V. (2017). Opening the Cages of Faujasite-Type Zeolite. Journal of the American Chemical Society, 139(48), 17273-17276. doi:10.1021/jacs.7b10316Kacirek, H., & Lechert, H. (1976). Rates of crystallization and a model for the growth of sodium-Y zeolites. The Journal of Physical Chemistry, 80(12), 1291-1296. doi:10.1021/j100553a006Oleksiak, M. D., Muraoka, K., Hsieh, M., Conato, M. T., Shimojima, A., Okubo, T., … Rimer, J. D. (2017). Organic‐Free Synthesis of a Highly Siliceous Faujasite Zeolite with Spatially Biased Q 4 ( n Al) Si Speciation. Angewandte Chemie International Edition, 56(43), 13366-13371. doi:10.1002/anie.201702672Oleksiak, M. D., Muraoka, K., Hsieh, M., Conato, M. T., Shimojima, A., Okubo, T., … Rimer, J. D. (2017). Organic‐Free Synthesis of a Highly Siliceous Faujasite Zeolite with Spatially Biased Q 4 ( n Al) Si Speciation. Angewandte Chemie, 129(43), 13551-13556. doi:10.1002/ange.201702672Feng, G., Cheng, P., Yan, W., Boronat, M., Li, X., Su, J.-H., … Yu, J. (2016). Accelerated crystallization of zeolites via hydroxyl free radicals. Science, 351(6278), 1188-1191. doi:10.1126/science.aaf1559Feng, G., Wang, J., Boronat, M., Li, Y., Su, J.-H., Huang, J., … Yu, J. (2018). Radical-Facilitated Green Synthesis of Highly Ordered Mesoporous Silica Materials. Journal of the American Chemical Society, 140(14), 4770-4773. doi:10.1021/jacs.8b00093Shi, D., Xu, L., Chen, P., Ma, T., Lin, C., Wang, X., … Sun, J. (2019). Hydroxyl free radical route to the stable siliceous Ti-UTL with extra-large pores for oxidative desulfurization. Chemical Communications, 55(10), 1390-1393. doi:10.1039/c8cc09225gChen, X., Qiu, M., Li, S., Yang, C., Shi, L., Zhou, S., … Sun, Y. (2020). Gamma‐Ray Irradiation to Accelerate Crystallization of Mesoporous Zeolites. Angewandte Chemie International Edition, 59(28), 11325-11329. doi:10.1002/anie.202002886Chen, X., Qiu, M., Li, S., Yang, C., Shi, L., Zhou, S., … Sun, Y. (2020). Gamma‐Ray Irradiation to Accelerate Crystallization of Mesoporous Zeolites. Angewandte Chemie, 132(28), 11421-11425. doi:10.1002/ange.202002886Anbar, M., Meyerstein, D., & Neta, P. (1966). The Reactivity of Aromatic Compounds toward Hydroxyl Radicals. The Journal of Physical Chemistry, 70(8), 2660-2662. doi:10.1021/j100880a034Matthews, R. W. (1980). The Radiation Chemistry of the Terephthalate Dosimeter. Radiation Research, 83(1), 27. doi:10.2307/3575256García-Martínez, J., Johnson, M., Valla, J., Li, K., & Ying, J. Y. (2012). Mesostructured zeolite Y—high hydrothermal stability and superior FCC catalytic performance. Catalysis Science & Technology, 2(5), 987. doi:10.1039/c2cy00309kTSUTSUMI, K. (1972). Cumene-cracking activity of zeolite catalysts I. Effects of ion exchange and silica-to-alumina mole ratio. Journal of Catalysis, 24(1), 1-7. doi:10.1016/0021-9517(72)90002-4Corma, A., & Wojciechowski, B. W. (1982). The Catalytic Cracking of Cumene. Catalysis Reviews, 24(1), 1-65. doi:10.1080/0360245820807964