Hydrothermal Synthesis of Zn-ZSM5 Catalyst for xylene isomerizationHydrothermal Synthesis of Zn-ZSM5 Catalyst for xylene isomerization

Document Type : Research Paper

Authors

1 Department of Chemical Engineering, Faculty of Engineering, University of Sistan and Baluchestan, Zahedan, Iran

2 Department of Petrochemical, Iran Polymer and Petrochemical Institute (IPPI), Tehran, Iran

Abstract

The addition of Zinc to the synthesis of ZSM-5 catalysts (Si/Al=21) was studied in xylene isomerization reactions. Physicochemical characteristics of the prepared catalysts were evaluated by XRD, BET, SEM, FTIR, NH3-TPD and TG analyses. Zn incorporation strongly increased the strong acid (Brønsted) sites and reduced the weak acidity (Lewis). Higher strong acidity led to higher PX yield and Lower weak acidity led to lower coke formation and more catalytic stability. (0.5 wt.%)Zn-ZSM-5 as an efficient and stable catalyst for xylene isomerization reactions demonstrated high PX yield (18.5 wt.%), high EB conversion (43.6%) and low xylene loss (3.3 %).
 

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[1]. www. Exxonmobilchemical.com##
[2]. Gonçalves J. C. and Rodrigues A. E., “Thermodynamic equilibrium of Xylene isomerization in the liquid Phase,” Journal of Chemical and Engineering Data, Vol. 58,  No. 6, pp 1425-1428, 3013.##
[3]. Ono Y., “A survey of the mechanism in catalytic isomerization of alkanes,” Catalysis Today, Vol. 81, pp. 3-16, 2003.##
[4]. Brito A., García F. J., Alvarez-Galván M. C., Borges M. E., Díaz C. and de la Peña O Shea V. A., “Catalytic behaviour of Pt or Pd metal nanoparticles-zeolite bifunctional catalysts for n-pentane hydroisomerization,” Catalysis Communications, Vol. 8, pp. 2081-2086, 2007.##
[5]. Martines J. A., Perez-Pariente J., Sastre E., Corma A. and Jacobs P. A., “Isomerization and disproportionation of m-Xylene Selectivities Induced by the Void Structure of the Zeolite Framework,” Applied Catalysis A., Vol. 45 pp. 85-101, 1988.##
[6]. Bauer F., Chen W. H., Ernst H., Huang S. J., Freyer A. and Liu S. B., “Selectivity improvement in xylene isomerization,” Microporous and Mesoporous Materials, Vol. 72, pp. 81-89, 2004.##
[7]. Zheng S., Jentys A. and Lercher J. A., “Xylene isomerization with surface-modified HZSM-5 zeolite catalysts: An in situ IR study,” Journal of Catalysis, Vol. 241, pp. 304-311, 2006.##
[8]. Nasiru M. and Tukura, Al-Khattaf S., “Comparison studies of Xylene isomerization and disproportionation reactions between SSZ-33, TNU-9, mordenite and ZSM-5 zeolite catalysts,” Chemical Engineering Journal, Vol. 166, pp. 348-357, 2011.##
[9]. Rostamizadeh M. and Yaripour F., “Bifunctional and bimetallic Fe/ZSM-5 nanocatalysts for methanol to olefin reaction,” Fuel, Vol. 181, pp. 537-546, 2016.## 
[10]. Sari Z., Younesi H. and Kazemian H., “Synthesis of nanosized ZSM-5 zeolite using extracted silica from rice husk without adding any alumina source,” Applied Nanoscience, Vol. 5, pp. 737-745, 2015.##
[11]. Wang G. L., Wu W., Zan W., Bai X. F., Wang W. J., Qi X. and Kikhtyanin O. V., “Preparation of Zn-modified nano-ZSM-5 zeolite and its catalytic performance in aromatization of 1-hexene,” Vol. 25, pp. 1580-1586, 2015.##
[12]. Rasouli M., Atashi H., Mohebbi-kalhori D. and Yaghobi N., “Bifunctional Pt/Fe-ZSM-5 catalyst for Xylene isomerization,” Journal of the Taiwan Institute of Chemical Engineering, Vol. 78, pp. 438-446, 2017.##
[13]. Li F., Jiang Y., Yu L., Yang Z., Hou T. and Sun S., “Surface effect of natural zeolite (clinoptilolite) on the photocatalytic activity of TiO2,” Applied Surface Science, Vol. 252, pp. 1410-1416, 2005.##
[14]. Padro C. L., Rey E. A., Gonzalez Pena L. F. and Apesteguia C. R., “Activity, selectivity and stability of Zn-exchanged NaY and ZSM5 zeolites for the synthesis of o-hydroxyacetophe none by phenol acylation,” Microporous and Mesoporous Materials, Vol. 143, pp. 236-242, 2011.##
[15]. Feng R., Bai P., Liu S., Zhang P., Liu X., Yan Z., Zhang Z. and Gao X., “The application of mesoporous alumina with rich Brönsted acidic sites in FCC catalysts,” Applied Petrochemical Research, Vol. 4, Issue 4,  pp 367–372, 2014.##
[16]. Zhang Y., Zhou Y., Huang L., Zhou S., Sheng, Wang Q. and Zhang C., “Structure and catalytic properties of the Zn-modified ZSM-5 supported platinum catalyst for propane dehydrogenation,” Chemical Engineering Journal, Vol. 270: pp. 352–361, 2015.##
[17]. Guillon E., Lacombe S., Sozinho T., Magnoux P., Gnep S., Moreau P. and Guisnet M., “How to improve the selectivity of zeolitic catalysts in C8 aromatic cut isomerization,” Oil & Gas Science and Technology - Rev. IFP, Vol. 64, pp. 731-744, 2009.##
[18]. Silva J. M., Ribeiro M. F., Ribeiro F. R., Benazzi E. and Guisnet M., “Transformation of an ethylbenzene-o-xylene mixture on HMOR and Pt-HMOR catalysts. Comparison with ZSM-5 catalysts”. Applied Catalysis A: General, Vol. 125, pp. 15-27 ,1995.##