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化学学报
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化学学报 ›› 2010, Vol. 68 ›› Issue (18): 1781-1786.    下一篇

研究论文

Zn对Pt/SAPO-11催化剂物化及异构性能影响

刘维桥*,1，雷卫宁1，刘平2，尚通明1，任杰2，孙予罕2   

  1. (1江苏技术师范学院化学化工学院 常州 213001)
    (2中国科学院山西煤炭化学研究所 太原 030001)
  • 投稿日期:2010-02-11 修回日期:2010-04-28 发布日期:2010-05-17
  • 通讯作者: 刘维桥 E-mail:lwq@jstu.edu.cn
  • 基金资助:

    国家重点基础研究发展计划

Physicochemical and Isomerization Property of Zn-Pt/SAPO-11 Catalysts Promoted by Zn

Liu Weiqiao*,1 Lei Weining1 Liu Ping2 Shang Tongming1 Ren Jie2 Sun Yuhan2   

  1. (1 School of Chemistry and Chemical Engineering, Jiangsu Teachers University of Technology, Changzhou 213001)
    (2 Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001)
  • Received:2010-02-11 Revised:2010-04-28 Published:2010-05-17
  • Contact: LIU WeiQiao E-mail:lwq@jstu.edu.cn

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通过浸渍法制备了Pt/SAPO-11催化剂, 分步浸渍法制备了Zn-Pt/SAPO-11双金属催化剂. 通过X射线衍射、低温氮物理吸附、氨程序升温脱附和吡啶吸附红外等手段对所得样品进行了表征. 实验结果表明, 助剂Zn的引入导致了催化剂的比表面积和孔容降低, B酸量减少而L酸量增加, 总酸量有所增加. 在300～380 ℃范围内对正庚烷的临氢异构化反应考察发现, 引入金属助剂Zn可以明显改变正庚烷的转化率, 而对C7异构体的选择性影响不明显. 当Zn质量分数为0.2%, Pt质量分数为0.2%时, Zn-Pt/SAPO-11催化剂的正庚烷转化率及C7异构体收率达到最大值; Zn含量继续增加时, 正庚烷转化率及C7异构体收率均随之下降. 实验结果表明, 双功能催化剂中金属功能与酸性功能的匹配对正庚烷临氢异构化反应非常重要.

关键词: Pt/SAPO-11催化剂, Zn, 正庚烷, 临氢异构化反应

Monometallic catalyst Pt/SAPO-11 was prepared by impregnation method. Bimetallic catalyst Zn-Pt/SAPO-11 was prepared by sequential impregnation method. X-ray diffraction (XRD), nitrogen adsorption, temperature-programmed desorption of ammonia (NH3-TPD) and Fourier transform infrared spectroscopy (FT-IR) techniques were employed to analyze the natures of catalysts. The results show that the BET surface areas, porous volume and the number of Bronsted acid decrease slightly with the addition of metal additive Zn. However, the addition of additive Zn leads to an increasement in the number of Lewis acid and the total acidity of the catalyst. In addition, the catalytic performances of catalysts for the hydroisomerization of n-heptane at 300～380 ℃ were studied. The conversion of n-heptane is varied significantly and the selectivity of C7 isomers is not obviously affected by the addition of Zn to Pt/SAPO-11 catalyst. A maximum n-heptane conversion and C7 isomers yield over the Zn-Pt/SAPO-11 catalyst containing 0.2 wt% Zn and 0.2 wt% Pt is observed. However, further increase in Zn addition leads to a fall in the n-heptane conversion and C7 isomers yield. The results show that the synergistic effect between metallic function and acid function is very important for the bifunctional catalyst over the n-heptane hydroisomerization reaction.

Key words: Pt/SAPO-11 catalyst, Zn, n-heptane, hydroisomerization