Back
 MSA  Vol.10 No.4 , April 2019
A Two-Step Crystallization Route for Hierarchical SAPO-34 Molecular Sieves: Unique Structural Features and Catalytic Property for DTO
Abstract: The hierarchical structure can significantly improve the diffusion efficiency of the catalyst and regulate the product distribution. Therefore, the preparation of hierarchical SAPO-34 molecular sieve has been a hot research topic. With Cetyltrimethyl Ammonium Bromide (CTAB) and Diethylamine (DEA) as templates, a two-step crystallization process was employed to synthesize hierarchical SAPO-34 molecular sieves. We found that the aging process is vital for the formation of pure phase SAPO-34. It was investigated the relationship of crystallinity trend and mesoporous content with the crystallization time. The results showed that the prolongation of crystallization time was beneficial to enhance the crystallinity of the molecular sieve, but unfavourable to the retention of mesoporous structure. The formation process of hierarchical SAPO-34 molecular sieve involved agglomeration, disintegration, crystallization, re-agglomeration and growth. The hierarchical SAPO-34 molecular sieve with a satisfactory crystallinity and considerable mesoporous structure could be obtained after 36 hours of crystallization. Moreover, the sample had the most suitable acid strength as well as acid amount. The catalytic activity was investigated by catalytic dimethyl ether (DME) to olefin (DTO) reaction. It revealed that the conversion of DME and the selectivity to olefins over the hierarchical SAPO-34 molecular sieve were significantly enhanced with comparison to that over microporous SAPO-34 molecular sieve. The amount of coke deposition of the hierarchical SAPO-34 molecular sieve (14.2%) was lower than that over the microporous molecular sieve (16.5%). Meanwhile, the propylene selectivity of hierarchical SAPO-34 was higher than that of microporous SAPO-34 in the whole reaction. In a word, the hierarchical SAPO-34 molecular sieve synthesized in this study showed a longer catalytic life, higher coke deposition resistance and higher propylene selectivity.
Cite this paper: Li, G. , Li, Z. , Ren, X. , Zhang, Y. , Chen, Z. and Yu, J. (2019) A Two-Step Crystallization Route for Hierarchical SAPO-34 Molecular Sieves: Unique Structural Features and Catalytic Property for DTO. Materials Sciences and Applications, 10, 302-316. doi: 10.4236/msa.2019.104023.
References

[1]   Wilson, S. and Barger, P. (1999) The Characteristics of SAPO-34 Which Influence the Conversion of Methanol to Light Olefins. Microporous and Mesoporous Materials, 29, 117-126.
https://doi.org/10.1016/S1387-1811(98)00325-4

[2]   Chen, D., Moljord, K. and Holmen, A. (2012) A Methanol to Olefins Review: Diffusion, Coke Formation and Deactivation on SAPO Type Catalysts. Microporous and Mesoporous Materials, 164, 239-250.
https://doi.org/10.1016/j.micromeso.2012.06.046

[3]   Kustova, M.Y., Hasselriis, P. and Christensen, C.H. (2004) Mesoporous MEL Type Zeolite Single Crystal Catalysts. Catalysis Letters, 96, 205-211.
https://doi.org/10.1023/B:CATL.0000030122.37779.f4

[4]   Hereijgers, B.P.C., Bleken, F., Nilsen, M.H., Svelle, S., Lillerud, K.P., Bjorgen, M., Weckhuysen, B.M. and Olsbye, U. (2009) Product Shape Selectivity Dominates the Methanol-to-Olefins (MTO) Reaction over H-SAPO-34 Catalysts. Journal of Catalysis, 264, 77-87.
https://doi.org/10.1016/j.jcat.2009.03.009

[5]   Li, X.F., Wang, P., Di, C.Y., Li, Z.H., Gao, M. and Dou, T. (2016) The Preparation of Layered SAPO-34 Molecular Sieve with Double Ammonium Template and Its Catalytic Performance for MTO Reaction. Acta Petrolei Sinica (Petroleum Processing Section), 32, 1099-1105.

[6]   Wu, L., Liu, Z.Y., Qiu, M.H., Yang, C.G., Xia, L., Liu, X. and Sun, Y.H. (2014) Morphology Control of SAPO-34 by Microwave Synthesis and Their Performance in the Methanol to Olefins Reaction. Reaction Kinetics, Mechanisms and Catalysis, 111, 319-334.
https://doi.org/10.1007/s11144-013-0639-1

[7]   Pérez-Ramírez, J., Christensen, C.H., Egeblad, K., Christensen, C.H. and Groen, J.C. (2008) Hierarchical Zeolites: Enhanced Utilisation of Microporous Crystals in Catalysis by Advances in Materials Design. Chemical Society Reviews, 37, 2530-2542.
https://doi.org/10.1039/b809030k

[8]   Fang, Y.M. and Hu, H.Q. (2006) An Ordered Mesoporous Aluminosilicate with Completely Crystalline Zeolite Wall Structure. JACS, 128, 10636-10637.
https://doi.org/10.1021/ja061182l

[9]   Na, K., Jo, C., Kim, J., Cho, K., Jung, J., Seo, Y., Messinger, R.J., Chmelka, B.F. and Ryoo, R. (2011) Directing Zeolite Structures into Hierarchically Nanoporous Architectures. Science, 333, 328-332.
https://doi.org/10.1126/science.1204452

[10]   Sun, Q.M., Wang, N., Bai, R.S., Chen, X.X. and Yu, J.H. (2016) Seeding Induced Nano-Sized Hierarchical SAPO-34 Zeolites: Cost-Effective Synthesis and Superior MTO Performance. Journal of Materials Chemistry A, 4, 14978-14982.
https://doi.org/10.1039/C6TA06613E

[11]   Chen, L., Xue, T., Zhu, S.Y. and Wang, Y.M. (2015) One-Step Synthesis of Hierarchical ZSM-5 Zeolite Microspheres Using Alkyl-Polyamines as Single Templates. Acta Physico-Chimica Sinica, 31, 181-188.

[12]   Ren, S., Liu, G.J., Wu, X., Chen, X.Q., Wu, M.H., Zeng, G.F., Liu, Z.Y. and Sun, Y.H. (2017) Enhanced MTO Performance over Acid Treated Hierarchical SAPO-34. Chinese Journal of Catalysis, 38, 123-130.
https://doi.org/10.1016/S1872-2067(16)62557-3

[13]   Wang, Y.L., Li, X.L., Ma, H., Zhang, H., Jiang, Y., Wang, H., Li, Z. and Wu, J.H. (2017) Effect of the Desilication of H-ZSM-5 by Alkali Treatment on the Catalytic Performance in Fischer-Tropsch Synthesis. Reaction Kinetics, Mechanisms and Catalysis, 120, 775-790.
https://doi.org/10.1007/s11144-016-1120-8

[14]   Varzaneh, A.Z., Towfighi, J. and Sahebdelfar, S. (2016) Carbon Nanotube Templated Synthesis of Metal Containing Hierarchical SAPO-34 Catalysts: Impact of the Preparation Method and Metal Avidities in the MTO Reaction. Microporous and Mesoporous Materials, 236, 1-12.
https://doi.org/10.1016/j.micromeso.2016.08.027

[15]   Shen, X.F., Mao, W.T., Ma, Y.H., Xu, D.D., Wu, P., Terasaki, O., Han, L. and Che, S.A. (2017) A Hierarchical MFI Zeolite with a Two-Dimensional Square Mesostructure. Angewandte Chemie International Edition, 57, 724-728.
https://doi.org/10.1002/anie.201710748

[16]   SharifiPajaie, H. and Taghizadeh, M. (2016) Methanol Conversion to Light Olefins over Surfactant-Modified Nanosized SAPO-34. Reaction Kinetics, Mechanisms and Catalysis, 118, 701-717.
https://doi.org/10.1007/s11144-016-1023-8

[17]   Chen, L., Wang, R.W., Ding, S., Liu, B.B., Xia, H., Zhang, Z.T. and Qiu, S.L. (2010) Synthesis and Characterization of SAPO-34-H (Hierarchical). Chemical Journal of Chinese Universities, 31, 1693-1696.

[18]   Jin, L.J., Liu, S.B., Xie, T., Wang, Y.T., Guo, X.H. and Hu, H.Q. (2014) Synthesis of Hierarchical ZSM-5 by Cetyltrimethylammonium Bromide Assisted Self-Assembly of Zeolite Seeds and Its Catalytic Performances. Reaction Kinetics, Mechanisms and Catalysis, 113, 575-584.
https://doi.org/10.1007/s11144-014-0743-x

[19]   Jin, Y.Y., Sun, Q., Qi, G.D., Yang, C.G., Xu, J., Chen, F., Meng, X.J., Deng, F. and Xiao, F.S. (2013) Solvent-Free Synthesis of Silicoalu-minophosphate Zeolites. Angewandte Chemie International Edition, 52, 9172-9175.
https://doi.org/10.1002/anie.201302672

[20]   Zhu, J., Cui, Y., Wang, Y. and Wei, F. (2009) Direct Synthesis of Hierarchical Zeolite from a Natural Layered Material. Chemical Communications, 45, 3282-3284.
https://doi.org/10.1039/b902661d

[21]   Zhao, D.Y., Wan, Y. and Zhou, W.Z. (2016) Ordered Mesoporous Molecular Sieve Materials. Higher Education Press, Beijing.

[22]   Karlsson, A., Stocker, M. and Schmidt, R. (1999) Composites of Micro- and Mesoporous Materials: Simultaneous Syntheses of MFI/MCM-41 like Phases by a Mixed Template Approach. Microporous and Mesoporous Materials, 27, 181-192.
https://doi.org/10.1016/S1387-1811(98)00252-2

[23]   Zhao, D.P., Zhang, Y., Li, Z., Wang, Y. and Yu, J.Q. (2017) Synthesis of SAPO-18/34 Intergrowth Zeolites and Their Enhanced Stability for Dimethyl Ether to Olefins. RSC Advances, 7, 939-946.
https://doi.org/10.1039/C6RA25080G

[24]   Liu, H.X., Xie, Z.K., Zhang, C.F., Chen, Q.L. and Yang, Y.Q. (2003) Effects of Silicon Source Content and Crystallization Time on the Structure and Catalytic Performance of SAPO-34 Molecular Sieve. Chinese Journal of Inorganic Chemistry, 19, 240-246.

[25]   Tan, J., Liu, Z.M., He, C.Q., Liu, X.C., Han, X.W., Zhai, R.S. and Bao, X.H. (1999) Method and Mechanism of Si Incorporation into Lattice of SAPO-34 Molecular Sieve. Chinese Journal of Catalysis, 20, 227-232.

[26]   He, C.Q., Liu, Z.M., Yang, L.X. and Cai, G.Y. (1995) Adjusting the Crystallite Size of SAPO-34 Molecular Sieve by the Dual Templatte Method. Chinese Journal of Catalysis, 16, 33-37.

[27]   Qi, G.Z., Xie, Z.K., Yang, W.M., Zhong, S.Q., Liu, H.X., Zhang, C.F. and Chen, Q.L. (2007) Behaviors of Coke Deposition on SAPO-34 Catalyst during Methanol Conversion to Light Olefins. Fuel Processing Technology, 88, 437-441.
https://doi.org/10.1016/j.fuproc.2006.11.008

[28]   Chen, D., Rebo, H.P., Moljord, K. and Holmen, A. (1997) The Role of Coke Deposition in the Conversion of Methanol to Olefins over SAPO-34. Studies in Surface Science and Catalysis, 111, 159-166.
https://doi.org/10.1016/S0167-2991(97)80151-6

[29]   Martínez, A., Peris, E., Derewinski, M. and Burkat-Dulakb, A. (2011) Improvement of Catalyst Stability during Methane Dehydroaromatization (MDA) on Mo/HZSM-5 Comprising Intracrystalline Mesopores. Catalysis Today, 169, 75-84.
https://doi.org/10.1016/j.cattod.2010.11.063

[30]   Kim, H.S., Lee, S.G., Kim, Y.H., Lee, D.H., Lee, J.B. and Park, C.S. (2013) Improvement of Lifetime Using Transition Metal-Incorporated SAPO-34 Catalysts in Conversion of Dimethyl Ether to Light Olefins. Journal of Nanomaterials, 2013, Article ID: 679758.

[31]   Wen, D.F., Liu, Q., Fei, Z.Y., Yang, Y.R., Zhang, Z.X., Chen, X., Tang, J.H., Cui, M.F. and Qiao, X. (2017) Organosilane-Assisted Synthesis of Hierarchical Porous ZSM-5 Zeolite as a Durable Catalyst for Light-Olefins Production from Chloromethane. Industrial & Engi-neering Chemistry Research, 57, 446-455.
https://doi.org/10.1021/acs.iecr.7b02332

 
 
Top