SCI和EI收录∣中国化工学会会刊

Chinese Journal of Chemical Engineering ›› 2014, Vol. 22 ›› Issue (8): 869-874.DOI: 10.1016/j.cjche.2014.06.008

• 第四届整体式结构化催剂与反应器国际会议专栏 • 上一篇    下一篇

Synthesis of ITQ-2 Zeolites and Catalytic Performance in n-Dodecane Cracking

Jiangge Hao1, Ying Wang1, Guozhu Liu1, Jingwen Zhang1, Guozhu Li1, Xuesong Ma2   

  1. 1. Key Laboratory of Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China;
    2. Science and Technology on Scramjet Laboratory, Beijing 100074, China
  • 收稿日期:2013-12-24 修回日期:2014-01-03 出版日期:2014-08-28 发布日期:2014-11-04
  • 通讯作者: Guozhu Li

Synthesis of ITQ-2 Zeolites and Catalytic Performance in n-Dodecane Cracking

Jiangge Hao1, Ying Wang1, Guozhu Liu1, Jingwen Zhang1, Guozhu Li1, Xuesong Ma2   

  1. 1. Key Laboratory of Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China;
    2. Science and Technology on Scramjet Laboratory, Beijing 100074, China
  • Received:2013-12-24 Revised:2014-01-03 Online:2014-08-28 Published:2014-11-04

摘要: ITQ-2 zeolites were prepared by sequential alkali-swelling and ultrasonic-delamination of precursor MCM-22 and characterized by X-ray powder diffraction, scanning electron microscopy, nitrogen adsorption-desorption, ammonia temperature-programmed desorption and in-situ Fourier-transform infrared spectroscopy. The delamination induced a change in the morphology of ITQ-2 zeolites from aggregated thin platelets to scattered platelets, together with a significant increase in external specific surface area, which reached a plateau at the ultrasonic treatment time of 3 h. The catalytic cracking of n-dodecane over ITQ-2 zeolites was evaluated with ITQ-2 coated on the inside wall of a tubular reactor at 550℃ and 4 MPa. The sample obtained by ultrasonic treatment of 3 h (ITQ-2-3) gave the highest initial conversion of n-dodecane, whereas those of 5 h and 1 h gave the conversion even lower than MCM-22, which was in agreement with the trend of the ratio of strong Lewis acid to the total acid amount. Although the amount of cokes deposited on ITQ-2-3 was larger than that on MCM-22, the former deactivated slowly, suggesting that a large external specific surface area benefits the stability of zeolite coatings.

关键词: MCM-22 zeolite, ITQ-2 zeolite, Swelling, Delamination, Catalytic cracking, n-Dodecane

Abstract: ITQ-2 zeolites were prepared by sequential alkali-swelling and ultrasonic-delamination of precursor MCM-22 and characterized by X-ray powder diffraction, scanning electron microscopy, nitrogen adsorption-desorption, ammonia temperature-programmed desorption and in-situ Fourier-transform infrared spectroscopy. The delamination induced a change in the morphology of ITQ-2 zeolites from aggregated thin platelets to scattered platelets, together with a significant increase in external specific surface area, which reached a plateau at the ultrasonic treatment time of 3 h. The catalytic cracking of n-dodecane over ITQ-2 zeolites was evaluated with ITQ-2 coated on the inside wall of a tubular reactor at 550℃ and 4 MPa. The sample obtained by ultrasonic treatment of 3 h (ITQ-2-3) gave the highest initial conversion of n-dodecane, whereas those of 5 h and 1 h gave the conversion even lower than MCM-22, which was in agreement with the trend of the ratio of strong Lewis acid to the total acid amount. Although the amount of cokes deposited on ITQ-2-3 was larger than that on MCM-22, the former deactivated slowly, suggesting that a large external specific surface area benefits the stability of zeolite coatings.

Key words: MCM-22 zeolite, ITQ-2 zeolite, Swelling, Delamination, Catalytic cracking, n-Dodecane