波谱学杂志

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用固体核磁方法研究MCM-22分子筛中的Al状态

罗晴1, 程谟杰2, 邓风1*   

  1. 1.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;
    2.中国科学院大连化学物理研究所 催化基础国家重点实验室, 大连  116023
  • 收稿日期:2001-03-21 出版日期:2001-06-05 发布日期:2001-06-05
  • 作者简介:罗晴(1976-),男,博士研究生.*通讯联系人
  • 基金资助:

    国家自然科学基金资助项目(批准号:29703009,29973058).

CHARACTERIZATION OF Al SPECIES IN MCM-22 ZEOLITE BY SOLID STATE NMR

LUO Qing1, CHENG Mo-jie2, DENG Feng1*   

  1. 1.State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, Wuhan Institute of Physics and Mathematics, The Chinese. Academy of Sciences, Wuhan 430071; 2.State Key Lab. of Catalyst, Dalan Institute of Chemical Physics, The Chinese Academy of Sciences, Dalan 116023
  • Received:2001-03-21 Online:2001-06-05 Published:2001-06-05
  • About author:*Corresponding author
  • Supported by:

    国家自然科学基金资助项目(批准号:29703009,29973058).

摘要:

用固体NMR技术研究了新型分子筛MCM-22在不同水合状态下的27Al谱和1H谱.并用新的1H/27Al双共振方法TRAPDOR对MCM-22分子筛的各种铝状态进行了研究,得到了样品脱水后B酸位(Bronsted)、L酸位(Lewis)以及非骨架Al(OH)的四极耦合常数.

关键词: MCM-22, TRAPDOR, 酸位, 四极矩, 偶合常数

Abstract:

MCM-22 is a new molecular sieve which is expected to be widely used in chemical industry. In this paper we study the 27Al species of different acid sites in the MCM-22. 27Al spectra of samples rehydrated in differently extent have been acquired. It is difficult to get high resolution 27Al spectrum of the dehydration powder sample directly because of the existence of strong quadrupole interaction which comes from asymmetric local chemical environment. In order to overcome the strong quadrupole interaction of 27Al, the double resonance NMR method 1H/27Al TRAPDOR is used in this study. Quadrupole coupling constants (QCC) for aluminum species are abtained. By calculation of the second order quandrupole line width of these aluminum species , it can be concluded that 4-, 3-coordinate framework aluminum and extra-framework alumium are all the source of the “NMR invisible aluminum”.

Key words:

stants

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