Enhancing hydrothermal stability of framework Al in ZSM-5: From the view on the transformation between P and Al species by solid-state NMR spectroscopy

doi:10.1016/j.cjche.2020.07.039

摘要/Abstract

摘要： HZSM-5, with good surface acidity and shape selectivity, was reported as hydrocarbon cracking catalyst for multiple decades, however the hydrothermal stability, especially dealumination of tetrahedrally coordinated framework aluminum (TFAl), has been proved extensively as one of the major challenges during reactionregeneration process. Phosphorus was proposed to stabilize TFAl and indeed it enhanced the hydrothermal stability. Unfortunately, most of the phosphorus species would remain outside of the zeolite pore, mainly as polyphosphate species, and block the micropore severely, with only a limited portion introduced into the channel being able to interact with TFAl. Enlarging the pore size by alkali treatment (desilication) is one of the most convinced methods, but the details about specific P species during alkali treatment and its transformation upon hydrothermal activation is not acquired, thus the mechanism has not been fully understood. Herein, the P-containing species and its transformation during direct P modification and acid/alkali treatment followed by P modification have been studied, and the mechanism on the interaction between P and Al species has been investigated, using several analytical methods, especially Solid-state nuclear magnetic resonance (SSNMR) spectroscopy. It was found that the combination of desilication and subsequent phosphorus modification can enhance the activity of the ZSM-5 for the cracking of ethylcyclohexane, due to the better hydrothermal stabilization of acid sites by the enhanced interaction between phosphorus and TFAl, resulting from the improved accessibility of TFAl because of the successful generation of mesoporosity. Whereas the acid treatment followed by phosphorus modification, with declined retention of crystallinity and P/Al ratio, monoclinic/orthorhombic transition during steam activation, and the failed generation of mesopores, would cause obvious aggregation of the phosphorus species and could not improve the hydrothermal stability of the ZSM-5effectively, and the direct phosphatation turned out much worse. Finally, a specific index that the intensity of the signal at 39 in ²⁷Al MAS NMR spectra before steam activation was proposed as the indicator for determining the efficiency of phosphorus modification. And the proposed mechanism on the interaction between phosphorus and TFAl during the phosphorus modification could also be applicable in other zeolites.

关键词: Phosphorus modification, TFAl, NaOH/alkali treatment, Interaction, ZSM-5

Abstract: HZSM-5, with good surface acidity and shape selectivity, was reported as hydrocarbon cracking catalyst for multiple decades, however the hydrothermal stability, especially dealumination of tetrahedrally coordinated framework aluminum (TFAl), has been proved extensively as one of the major challenges during reactionregeneration process. Phosphorus was proposed to stabilize TFAl and indeed it enhanced the hydrothermal stability. Unfortunately, most of the phosphorus species would remain outside of the zeolite pore, mainly as polyphosphate species, and block the micropore severely, with only a limited portion introduced into the channel being able to interact with TFAl. Enlarging the pore size by alkali treatment (desilication) is one of the most convinced methods, but the details about specific P species during alkali treatment and its transformation upon hydrothermal activation is not acquired, thus the mechanism has not been fully understood. Herein, the P-containing species and its transformation during direct P modification and acid/alkali treatment followed by P modification have been studied, and the mechanism on the interaction between P and Al species has been investigated, using several analytical methods, especially Solid-state nuclear magnetic resonance (SSNMR) spectroscopy. It was found that the combination of desilication and subsequent phosphorus modification can enhance the activity of the ZSM-5 for the cracking of ethylcyclohexane, due to the better hydrothermal stabilization of acid sites by the enhanced interaction between phosphorus and TFAl, resulting from the improved accessibility of TFAl because of the successful generation of mesoporosity. Whereas the acid treatment followed by phosphorus modification, with declined retention of crystallinity and P/Al ratio, monoclinic/orthorhombic transition during steam activation, and the failed generation of mesopores, would cause obvious aggregation of the phosphorus species and could not improve the hydrothermal stability of the ZSM-5effectively, and the direct phosphatation turned out much worse. Finally, a specific index that the intensity of the signal at 39 in ²⁷Al MAS NMR spectra before steam activation was proposed as the indicator for determining the efficiency of phosphorus modification. And the proposed mechanism on the interaction between phosphorus and TFAl during the phosphorus modification could also be applicable in other zeolites.

Key words: Phosphorus modification, TFAl, NaOH/alkali treatment, Interaction, ZSM-5

Lei Han, Ying Ouyang, Enhui Xing, Yibin Luo, Zhijian Da. Enhancing hydrothermal stability of framework Al in ZSM-5: From the view on the transformation between P and Al species by solid-state NMR spectroscopy[J]. 中国化学工程学报, 2020, 28(12): 3052-3060.

参考文献

[1] N.Y. Chen, W.W. Kaeding, F.G. Dwyer, Para-directed aromatic reactions over shapeselective molecular sieve zeolite catalysts, Chem. 11(1980) 6783-6784.
[2] G. Zhao, J. Teng, Z. Xie, W. Jin, W. Yang, Q. Chen, Y. Tang, Effect of phosphorus on HZSM-5 catalyst for C 4-olefin cracking reactions to produce propylene, J. Catal. 248(2007) 29-37.
[3]. V.D.B. He,B.M. Weckhuysen, Phosphorus promotion and poisoning in zeolite-based materials:synthesis, characterisation and catalysis, Chem. Soc. Rev. 44(2015) 7406-7428.
[4] Y. Chu, X. Gao, X. Zhang, G. Xu, G. Li, A. Zheng, Identifying the effective phosphorous species over modified P-ZSM-5 zeolite:a theoretical study, Phys.Chem.Chem.Phys. 20(2018) 11702-11712.
[5] G. Lischke, R. Eckelt, H.G. Jerschkewitz, B. Parlitz, E. Schreier, W. Storek, B. Zibrowius, G. Oehlmann, ChemInform abstract:spectroscopic and physicochemical characterization of P-modified H-ZSM-5, J. Catal. 132(1991) 229-243.
[6] J. Zhuang, D. Ma, G. Yang, Z. Yan, X. Liu, X. Liu, X. Han, X. Bao, P. Xie, Z. Liu, Solid-state MAS NMR studies on the hydrothermal stability of the zeolite catalysts for residual oil selective catalytic cracking, J. Catal. 228(2004) 234-242.
[7] T. Blasco, A. Corma, J. Martínez-Triguero, Hydrothermal stabilization of ZSM-5 catalytic-cracking additives by phosphorus addition, J. Catal. 237(2006) 267-277.
[8] G. Caeiro, P. Magnoux, J.M. Lopes, F.R. Ribeiro, S.M.C. Menezes, A.F. Costa, H.S. Cerqueira, Stabilization effect of phosphorus on steamed H-MFI zeolites, Appl. Catal. A-Gen. 314(2006) 160-171.
[9] L. Dan, W.C. Choi, C.W. Lee, Y.K. Na, J.L. You, C.H. Shin, K.P. Yong, Steaming and washing effect of P/HZSM-5 in catalytic cracking of naphtha, Catal. Today 164(2011) 154-157.
[10] A. Corma, J. Mengual, P.J. Miguel, Steam catalytic cracking of naphtha over ZSM-5 zeolite for production of propene and ethene:micro and macroscopic implications of the presence of steam, Appl. Catal. A-Gen. 417-418(2012) 121-134.
[11] J. Ding, M. Wang, L. Peng, N. Xue, Y. Wang, M.Y. He, Combined desilication and phosphorus modification for high-silica ZSM-5 zeolite with related study of hydrocarbon cracking performance, Appl. Catal. A-Gen. 503(2015) 147-155.
[12] W.W. Keading, C. Chu, L.B. Young, S.A. Butter, ChemInform abstract:shape-selective reactions with zeolite catalysts. Part 2. Selective disproportionation of toluene to produce benzene and p-xylene, J. Catal. 12(1981) 392-398.
[13] E.T. Vogt, B.M. Weckhuysen, Fluid catalytic cracking:recent developments on the grand old lady of zeolite catalysis, Chem. Soc. Rev. 44(2015) 7342-7370.
[14] N. Xue, X. Chen, N. Lei, X. Guo, W. Ding, C. Yi, G. Min, Z. Xie, Understanding the enhancement of catalytic performance for olefin cracking:hydrothermally stable acids in P/HZSM-5, J. Catal. 248(2007) 20-28.
[15] G. Zhao, J. Teng, Z. Xie, W. Jin, T. Yi, Effect of phosphorus on HZSM-5 catalyst for C 4-olefin cracking reactions to produce propylene, J. Catal. 248(2007) 29-37.
[16] G. Jiang, L. Zhang, Z. Zhao, X. Zhou, A. Duan, C. Xu, J. Gao, Highly effective P-modified HZSM-5 catalyst for the cracking of C 4 alkanes to produce light olefins, Appl. Catal. A-Gen. 340(2008) 176-182.
[17] N. Xue, L. Nie, D. Fang, X. Guo, J. Shen, W. Ding, Y. Chen, Synergistic effects of tungsten and phosphorus on catalytic cracking of butene to propene over HZSM-5, Appl. Catal. A-Gen. 352(2009) 87-94.
[18] M. Derewinski, P. Sarv, X. Sun, S. Müller, A.C.V. Veen, J.A. Lercher, Reversibility of the modification of HZSM-5 with phosphate anions, J. Phys. Chem. C 118(2014) 6122-6131.
[19] V.D.B. He, L.R. Aramburo, B. Arstad, J.J. Dynes, J. Wang, B.M. Weckhuysen, Phosphatation of zeolite H-ZSM-5:a combined microscopy and spectroscopy study, Chemphyschem. 15(2014) 283-292.
[20] V.D.B. He, F. Meirer, S. Kalirai, J. Wang, B.M. Weckhuysen, Hexane cracking over steamed phosphated zeolite H-ZSM-5:promotional effect on catalyst performance and stability, Chem-Eur. J. 20(2014) 16922-16932.
[21] S.M.C.D. Menezes, Y.L. Lam, K. Damodaran, M. Pruski, Modification of H-ZSM-5 zeolites with phosphorus. 1. Identification of aluminum species by ²⁷Al solid-state NMR and characterization of their catalytic properties, Micropor. Mesopor. Mat. 95(2006) 286-295.
[22] D. Zhang, R. Wang, X. Yang, Effect of P content on the catalytic performance of Pmodified HZSM-5 catalysts in dehydration of ethanol to ethylene, Catal. Lett. 124(2008) 384-391.
[23] Y.J. Lee, J.M. Kim, J.W. Bae, C.H. Shin, K.W. Jun, Phosphorus induced hydrothermal stability and enhanced catalytic activity of ZSM-5 in methanol to DME conversion, Fuel. 88(2009) 1915-1921.
[24] K. Ramesh, L.M. Hui, Y.F. Han, A. Borgna, Structure and reactivity of phosphorous modified H-ZSM-5 catalysts for ethanol dehydration, Catal. Commun. 10(2009) 567-571.
[25] K. Ramesh, C. Jie, Y.F. Han, A. Borgna, Synthesis, characterization, and catalytic activity of phosphorus modified H-ZSM-5 catalysts in selective ethanol dehydration, Ind. Eng. Chem. Res. 49(2010) 4080-4090.
[26] Y. Ji, H. Yang, Q. Zhang, W. Yan, Phosphorus modification increases catalytic activity and stability of ZSM-5 zeolite on supercritical catalytic cracking of n-dodecane, J. Solid State Chem. 251(2017) 7-13.
[27] M.J.B. Cardoso, D.D.O. Rosas, L.Y. Lau, Surface P and Al distribution in P-modified ZSM-5 zeolites, Adsorption. 11(2005) 577-580.
[28] W.W. Kaeding, S.A. Butter, Production of chemicals from methanol:I. Low molecular weight olefins, J. Catal. 61(1980) 155-164.
[29] G. Seo, R. Ryoo, 31 P, 27 Al, and 129 Xe NMR study of phosphorus-impregnated HZSM-5 zeolite catalysts, J. Catal. 21(1990) 224-230.
[30] G. Yang, J. Zhuang, Y. Wang, D. Zhou, M. Yang, X. Liu, X. Han, X. Bao, Enhancement on the hydrothermal stability of ZSM-5 zeolites by the cooperation effect of exchanged lanthanum and phosphoric species, J. Mol. Struct. 737(2005) 271-276.
[31] K. Damodaran, J.W. Wiench, S.M.C.D. Menezes, Y.L. Lam, J. Trebosc, J.P. Amoureux, M. Pruski, Modification of H-ZSM-5 zeolites with phosphorus. 2. Interaction between phosphorus and aluminum studied by solid-state NMR spectroscopy, Micropor. Mesopor. Mat. 95(2006) 296-305.
[32] M. Göhlich, W. Reschetilowski, S. Paasch, Spectroscopic study of phosphorus modified H-ZSM-5, Micropor. Mesopor. Mat. 142(2011) 178-183.
[33] H.E.V.D. Bij, D. Cicmil, J. Wang, F. Meirer, F.F.M.F.D. Groot, B.M. Weckhuysen, Aluminum-phosphate binder formation in zeolites as probed with X-ray absorption microscopy, J. Am. Chem. Soc. 136(2014) 17774-17787.
[34] A. Zheng, S. Li, S.B. Liu, F. Deng, Acidic properties and structure-activity correlations of solid acid catalysts revealed by solid-state NMR spectroscopy, Acc. Chem. Res. 49(2016) 655-663.
[35] A. Zheng, S.B. Liu, F. Deng, ³¹P NMR chemical shifts of phosphorus probes as reliable and practical acidity scales for solid and liquid catalysts, Chem. Rev. 117(2017) 12475-12531.
[36] E.L. Wu, S.L. Lawton, D.H. Olson, A.C. Rohrman, G.T. Kokotailo, ZSM-5-type materials. Factors affecting crystal symmetry, J. Phys. Chem. A 83(1979) 2777-2781.
[37] X. Gao, Z. Tang, G. Lu, G. Cao, D. Li, Z. Tan, Butene catalytic cracking to ethylene and propylene on mesoporous ZSM-5 by desilication, Solid State Sci. 12(2010) 1278-1282.
[38] H. Mochizuki, T. Yokoi, H. Imai, S. Namba, J.N. Kondo, T. Tatsumi, Effect of desilication of H-ZSM-5 by alkali treatment on catalytic performance in hexane cracking, Appl. Catal. A-Gen. 449(2012) 188-197.
[39] S.M. Abubakar, D.M. Marcus, J.C. Lee, J.O. Ehresmann, C.Y. Chen, P.W. Kletnieks, D.R. Guenther, M.J. Hayman, M. Pavlova, J.B. Nicholas, Structural and mechanistic investigation of a phosphate-modified HZSM-5 catalyst for methanol conversion, Langmuir. 22(2006) 4846-4852.
[40] M. Ogura, S. Shinomiya, J. Tateno, Y. Nara, M. Nomura, E. Kikuchi, M. Matsukata, Alkali-treatment technique-new method for modification of structural and acidcatalytic properties of ZSM-5 zeolites, Appl. Catal. A-Gen. 219(2001) 33-43.
[41] J.S. Jung, J.W. Park, G. Seo, Catalytic cracking of n-octane over alkali-treated MFI zeolites, Appl. Catal. A-Gen. 288(2005) 149-157.
[42] Y.Q. Song, Y.L. Feng, F. Liu, C.L. Kang, X.L. Zhou, L.Y. Xu, G.X. Yu, Effect of variations in pore structure and acidity of alkali treated ZSM-5 on the isomerization performance, J. Mol. Catal. A-Chem. 310(2009) 130-137.
[43] K. Sadowska, A. Wach, Z. Olejniczak, P. Kuśtrowski, J. Datka, Hierarchic zeolites:zeolite ZSM-5 desilicated with NaOH and NaOH/tetrabutylamine hydroxide, Micropor. Mesopor. Mat. 167(2013) 82-88.
[44] F. Thibault-Starzyk, I. Stan, S. Abelló, A. Bonilla, K. Thomas, C. Fernandez, J.-P. Gilson, J. Pérez-Ramírez, Quantification of enhanced acid site accessibility in hierarchical zeolites-the accessibility index, J. Catal. 264(2009) 11-14.
[45] J. Caro, M. Buelow, M. Derewinski, J. Haber, M. Hunger, J. Kaerger, H. Pfeifer, W. Storek, B. Zibrowius, ChemInform abstract:NMR and IR studies of zeolite H-ZSM-5 modified with orthophosphoric acid, Cheminform. 21(1990) 367-375.
[46] N. Xue, R. Olindo, J.A. Lercher, Impact of forming and modification with phosphoric acid on the acid sites of HZSM-5, J. Phys. Chem. C 114(2010) 15763-15770.
[47] S.M. Abubakar, D.M. Marcus, J.C. Lee, J.O. Ehresmann, C.Y. Chen, P.W. Kletnieks, D.R. Guenther, M.J. Hayman, M. Pavlova, J.B. Nicholas, Structural and mechanistic investigation of a phosphate-modified HZSM-5 catalyst for methanol conversion, Langmuir. 22(2006) 4846-4852.
[48] P. Zhao, B. Boekfa, T. Nishitoba, N. Tsunoji, M. Ehara, Theoretical study on ³¹P NMR chemical shifts of phosphorus-modified CHA zeolites, Micropor. Mesopor. Mat. 294(2019) 109908-109920.