波谱学杂志 >

2021 , Vol. 38 >Issue 4: 514 - 522

DOI: https://doi.org/10.11938/cjmr20212927

 

六氟硅酸铵后处理对H-ZSM-5分子筛酸性影响的固体NMR研究

  • 王永祥 ,
  • 王强 ,
  • 徐君 ,
  • 夏清华 ,
  • 邓风
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  • 1. 湖北大学, 有机化工新材料湖北省协同创新中心＆有机功能分子合成与应用教育部重点实验室, 湖北 武汉 430062
    2. 中国科学院精密测量科学与技术创新研究院, 波谱与原子分子物理国家重点实验室, 武汉磁共振中心, 湖北 武汉 430071

收稿日期: 2021-06-29

  网络出版日期: 2021-08-26

基金资助

国家自然科学基金资助项目(21733013);国家自然科学基金资助项目(91745111)

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The Effects of Ammonium Hexafluorosilicate Post-Treatment on the Acidity of H-ZSM-5 Zeolite Studied by Solid-State NMR Spectroscopy

  • Yong-xiang WANG ,
  • Qiang WANG ,
  • Jun XU ,
  • Qing-hua XIA ,
  • Feng DENG
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  • 1. Ministry-of-Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Collaborative Innovation Center for Advanced Organic Chemical Materials Co-constructed by the Province and Ministry, Hubei University, Wuhan 430062, China
    2. State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision, National Centre for Magnetic Resonance in Wuhan, Wuhan 430071, China

Received date: 2021-06-29

  Online published: 2021-08-26

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摘要

本文利用固体核磁共振（NMR）实验对六氟硅酸铵（AHFS）溶液洗涤前后H-ZSM-5分子筛上铝物种变化引起的酸性改变进行了研究.结果显示经AHFS洗涤处理后，分子筛上构成Brøsted酸的骨架四配位铝物种会部分减少；具有Lewis酸性的骨架三配位铝量在经AHFS脱铝处理后少量降低；同时AHFS温和脱铝的方式主要会引起分子筛上另一类具有Lewis酸性且含Al-OH的铝物种大量减少，从而导致处理后分子筛整体酸性的显著改变.

关键词： 六氟硅酸铵（AHFS）; 三甲基氧膦（TMPO）探针分子; 酸性; 固体核磁共振

本文引用格式

王永祥 , 王强 , 徐君 , 夏清华 , 邓风 . 六氟硅酸铵后处理对H-ZSM-5分子筛酸性影响的固体NMR研究[J]. 波谱学杂志, 2021 , 38(4) : 514 -522 . DOI: 10.11938/cjmr20212927

Abstract

In this study, solid-state nuclear magnetic resonance (NMR) spectroscopy was used to probe the changes of acidity of H-ZSM-5 zeolite caused by ammonium hexafluorosilicate (AHFS) washing-related changes of aluminium species. It was observed that the four-coordinate framework aluminum species with Brønsted acidity were partially reduced, while the tri-coordinated framework aluminum with Lewis acidity was slightly decreased after the AHFS treatment. However, AHFS washing was also found to induce mild dealumination and a significant reduction of aluminum species with Lewis acidity containing Al-OH group on zeolites, thus resulting in a remarkable change in the overall acidity of the zeolites.

Key words： ammonium hexafluorosilicate (AHFS); trimethylphosphine oxide (TMPO) probe molecules; acidity; solid-state nuclear magnetic resonance

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