Journal of Inorganic Materials ›› 2014, Vol. 29 ›› Issue (4): 357-363.DOI: 10.3724/SP.J.1077.2014.13377

• Research Paper • Previous Articles     Next Articles

Synthesis of ZSM-5/EU-1 Composite Zeolite and Its Application in Conversion of Methanol to Xylene

YANG Dong-Hua1, WANG Xin-Bo1, SHI Bao-Bao1, WU Zheng-Huang1, Li Xiao-Feng2, DOU Tao2,3   

  1. (1. College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024, China; 2. Research Institute of Special Chemicals, Taiyuan University of Technology, Taiyuan 030024, China; 3. CNPC Key Laboratory of Catalysis, College of Chemical Engineering, China University of Petroleum-Beijing, Beijing 102249, China)
  • Received:2013-07-20 Revised:2013-09-11 Published:2014-04-20 Online:2014-03-24
  • Contact:
  • About author:YANG Dong-Hua. E-mail: ydh1962@163.com
  • Supported by:

    National Key Basic Research Development Plan (973 Plan 2012CB215002); National Science Foundation (20973123); Nutural Science Foundation of Shanxi Province(2013011041-1); State Key Laboratory of Coal Conversion (11-12-603)

Abstract: Heteroatom-containing ZSM-5/EU-1 composite zeolites with porous structure were synthesized by hydrothermal method using silica sol, aluminum sulfate, sodium hydroxide, TPABr, boric acid and iron nitrate as raw materials, and EU-1 as crystal seed. The synthetic samples were investigated by XRD, SEM, N2 adsorption-desorption and NH3-TPD. Catalyst performance of the composite zeolites for conversion of methanol to xylene was evaluated on a continuous-flow reactor. The results show that the heteroatom-containing ZSM-5/EU-1 composite zeolite with good crystallinity has diffraction peaks for both ZSM-5 and EU-1. Its average pore size has been significantly enlarged and its amount and strength of acid were also increased, which benefited for the aromatization trend of methanol and the priority diffusion of xylene. Selectivity of aromatics in the oil phase can reach 84.70% when using B-ZSM-5/EU-1 as catalyst. It is found that the contents of xylene product are the highest both in B-ZSM-5/EU-1 and in Fe-ZSM-5/EU-1 catalytic products in the range of 41.32%–45.88% and 33.88%–39.16%, respectively. The reason why B-ZSM-5/EU-1 catalytic effect is better than that of Fe-ZSM-5/EU-1 is that the acidity of former is higher and pore diameter smaller (0.8060 nm), both characters favoring xylene formation. However, the selectivity of p-xylene in B-ZSM-5/EU-1 catalytic xylene products is in the range of 29.75%~47.47% which is lower than that of Fe-ZSM-5/ EU-1 with the highest of 53.75%. This result can be attributed to larger particle size of Fe-ZSM-5/EU-1 which provides a longer pore structure for the catalytic reaction so that o-xylene and m-xylene are easier to convert into p-xylene during the diffusion process.

Key words: seeding technique, ZSM-5/EU-1, acidity, xylene, selectivity

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