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化学学报
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化学学报 ›› 2005, Vol. 63 ›› Issue (4): 269-273. 上一篇    下一篇

研究论文

SO3/γ-Al2O3固体酸催化剂的制备、结构与酸性表征

姚瑞平1, 张铭金*,1,2, 杨俊2，易德莲1，徐君1; 邓风2,岳勇2, 叶朝辉2   

  1. (1武汉科技大学化学系 武汉 430081)
    (2中国科学院武汉物理与数学研究所 波谱与原子分子物理国家重点实验室 武汉 430071)
  • 投稿日期:2004-08-24 修回日期:2004-10-30 发布日期:2010-12-10
  • 通讯作者: 张铭金

Preparation of SO3/γ-Al2O3 Solid Acid Catalyst and Characterization of Its Structure and Acidity

YAO Rui-Ping1,ZHANG Ming-Jin*,1,2,YANG Jun2,YI De-Lian1
XU Jun1,DENG Feng2,YUE Yong2,YE Chao-Hui2   

  1. (1 Department of Chemistry, Wuhan University of Science and Technology, Wuhan 430081)
    (2 State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and
    Mathematics, Chinese Academy of Sciences, Wuhan 430071)
  • Received:2004-08-24 Revised:2004-10-30 Published:2010-12-10
  • Contact: ZHANG Ming-Jin

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用酸中和法制备了活性γ-Al2O3, 并在其表面负载SO3得到固体酸催化剂SO3/γ-Al2O3, 用XRD, TG-DTA, FT-IR，NMR, NH3-TPD等对其进行了结构和酸性研究. 结果表明: 在SO3/γ-Al2O3的制备过程中形成少量的Al2(SO4)3, 同时SO3与γ-Al2O3表面上的羟基反应, 形成强的Brönsted酸位, 根据1H/27Al 双共振(TRAPDOR)MAS NMR与FT-IR实验结果提出了Brönsted酸结构模型. SO3/γ-Al2O3表面存在两种不同强度的酸中心, 其酸强度大于分子筛HZSM-5, 但弱于传统的固体超强酸 /γ-Al2O3.

关键词: SO3/γ-Al2O3, 固体酸催化剂, 固体NMR, 酸位结构

A solid acid catalyst SO3/γ-Al2O3 was prepared by adsorption of SO3 gas onto the surfaces of activated γ-Al2O3. The structure and acidity of the catalyst were studied by XRD, NMR, FT-IR, TG-DTA and NH3-TPD method. The results indicated that SO3 reacted with activated γ-Al2O3 to form a small quantity of Al2(SO4)3, and at the same time, the adsorption of SO3 on the surface of γ-Al2O3 introduced two different kinds of Brönsted acid sites, which can be attributed to two different acid hydroxyl groups, including the bridging hydroxyl groups (S-OH-Al, giving rise to an 1H resonance at ca. δ 4.3) and the terminal hydroxyl groups attached to S atoms (S-OH, giving rise to an 1H resonance at ca. δ 11.2). The structure of Brönsted acid sites on the surface of catalyst SO3/γ-Al2O3 has been proposed based on 1H/27Al TRAPDOR and FT-IR results. The acid strength of SO3/γ-Al2O3 is stronger than that of zeolite HZSM-5, but still weaker than that of /γ-Al2O3, which is a conventional solid superacid catalyst.

Key words: SO3/γ-Al2O3, solid acid catalyst, solid-state NMR, acid site structure