EFFECTS OF PHOSPHORUS TEMPLATE AND SILICON SOURCES ON STRUCTURE AND CATALYTIC PERFORMANCE OF HIERARCHICAL ZSM-5 ZEOLITE

Abstract

Abstract: ZSM-5 molecular sieves with hierarchical porous structure were synthesized by using mixture of phosphorus-containing template TBPOH and TPAOH with different proportions, and characterized by XRD，BET，SEM，TEM，NH3-TPD and MAS NMR. The synergistic effect of TPAOH and TBPOH was investigated, by which the phosphorus-containing hier-ZSM-5 with fairly high degree of crystallinity can be obtained. The results showed that the morphology of ZSM-5 is regular and it shows higher specific surface area and pore volume when the molar ratio of TBPOH and TPAOH is 1∶1 with TEOS as the silicon source. The average pore size distributes at 4-10 nm and 50-70 nm. ZSM-5 zeolite rich in mesoporous structure was constituted by accumulation of small grains. Compared with conventional ZSM-5 molecular sieve，hier-ZSM-5 shows greater weak acidity and total amount of acidity. At same conversion of 1，3，5-triisopropylbenzene cracking reaction，the microporous ZSM-5 zeolite shows better selectivity for benzene and diisopropylbenzene，while the hier-ZSM-5 with mesopores shows more excellent selectivity for propylene and cumene.

Key words: phosphorus template, ZSM-5 molecular sieve, hierarchical pores, catalytic cracking

Li Peng Li Feng Liu Yujian Zheng Jiajun Li Wenlin Cui Xingyu Li Ruifeng. EFFECTS OF PHOSPHORUS TEMPLATE AND SILICON SOURCES ON STRUCTURE AND CATALYTIC PERFORMANCE OF HIERARCHICAL ZSM-5 ZEOLITE[J]. , 2018, 49(8): 21-27.

References

[1]赵晓波, 郭新闻, 王祥生.改性纳米-催化剂在汽油改质中的应用[J].石油学报石油加工, 2006, 22(6):20-23 [2]Christensen C H, Johannsen K, T?rnqvist E, et al.Mesoporous zeolite single crystal catalysts: Diffusion and catalysis in hierarchical zeolites[J].Catalysis Today, 2007, 128(3):117-122 [3]Serrano D P, Aguado J, Escola J M, et al.Influence of nanocrystalline HZSM-5 external surface on the catalytic cracking of polyolefins[J].Journal of Analytical & Applied Pyrolysis, 2005, 74(1):353-360 [4]Eduardo F S, Aguiar, M L, Murta V, et al.Silva Influence of external surface area of rare-earth containing Y zeolites on the cracking of 1,3,5-triisopropylbenzene[J].Zeolites, 1995, 15(7):620-623 [5]Larsen S C.Nanocrystalline Zeolites and Zeolite Structures:? Synthesis,Characterization,and Applications[J].Cheminform, 2008, 39(12):18464-18474 [6]Huang L, Wang Z, Sun J, et al.Fabrication of ordered porous structures by self-assembly of zeolite nanocrystalsJ. Amer. Chem. Soc. 2000,122(14): 3530-3531.[J].J. Amer. Chem. Soc., 2000, 122(14):3530-3531 [7]Huang L, Wang Z, Wang H, et al.Hierarchical porous structures by using zeolite nanocrystals as building blocks[J].Microporous & Mesoporous Materials, 2001, 48(1):73-78 [8]Janssen A H, Koster A J, Jong K P D.On the shape of the mesopores in zeolite Y: a three-dimensional transmission electron microscopy study combined with texture analysis[J].J. Phys. Chem. B, 2002, 106(46):11905-11909 [9]Zhu J, Zhu Y, Zhu L, et al.Highly mesoporous single-crystalline zeolite Beta synthesized using a nonsurfactant cationic polymer as a dual-function template J. Am. Chem. Soc.,2014,136: 2503-2510.[J].J. Am. Chem. Soc., 2014, 136(6):2503-2510 [10]Xue Z, Jinghong, Zhang T, et al.Synthesis of nanosized ZSM-5 zeolite with intracrystalline mesopores[J]. Materials Letters, 2012, 68:1-3.[J].Materials Letters, 2012, 68:1-3[J]. Materials Letters, 2012, 68:1-3 [11]Song W, Justice R E, Jones C A, et al.Size-dependent properties of nanocrystalline silicalite synthesized with systematically varied crystal sizes Langmuir,2004,20: 4696-4702.[J].Langmuir, 2004, 20(11):2503-2510 [12]Majano G, Darwiche A, Mintova S, et al.Seed-induced crystallization of nanosized Na-ZSM-5 crystals Ind. Eng. Chem. Res.,2009,48: 7084-7091.[J].Ind. Eng. Chem. Res., 2009, 48(15):7084-7091 [13]Zhu K, Egeblad K, Christensen C H.Mesoporous Carbon Prepared from Carbohydrate as Hard Template for Hierarchical Zeolites[J].Eur. J. Inorg. Chem., 2007, 2007(25):3955-3960 [14]Kustova M, Egeblad K, Zhu K, et al.Versatile Route to Zeolite Single Crystals with Controlled Mesoporosity: In situ Sugar Decomposition for Templating of Hierarchical Zeolites[J].Chem. Mater., 2007, 19(12):2915-2917 [15]Wei X, Smirniotis P G.Synthesis and characterization of mesoporous ZSM-12 by using carbon particles Micropor. Mesopor. Mater.,2006,89: 170-178.[J].Micropor. Mesopor. Mater., 2006, 89(1-3):170-178 [16]Védrine J C, Auroux A, Dejaifve P, et al.Catalytic and physical properties of phosphorus-modified ZSM-5 zeolite[J].Journal of Catalysis, 1982, 73(1):147-160 [17]Vinek H, Rumplmayr G, Lercher J A.Catalytic properties of postsynthesis phosphorus-modified H-ZSM5 zeolites[J].Journal of Catalysis, 1989, 115(2):291-300 [18]Zhuang J, Ma D, Yang G, et al.Solid-state MAS NMR studies on the hydrothermal stability of the zeolite catalysts for residual oil selective catalytic cracking[J].Journal of Catalysis, 2004, 228(1):234-242 [19]宋守强, 李明罡, 李黎声, 等.磷改性-分子筛的水热稳定性[J].石油学报石油加工, 2014, 30(2):194-203 [20]李剑, 谭猗生, 韩怡卓.磷水热改性-分子筛对二甲醚转化合成异构烷烃的催化性能[J].石油化工, 2009, 38(10):1038-1043