高等学校化学学报 ›› 1999, Vol. 20 ›› Issue (2): 272.

• 论文 • 上一篇    下一篇

水解对MCM-41分子筛的结构破坏作用

李惠云, 孙渝, 乐英红, 高滋   

  1. 复旦大学化学系, 上海 200433
  • 收稿日期:1998-03-10 出版日期:1999-02-24 发布日期:1999-02-24
  • 通讯作者: 高滋
  • 作者简介:李惠云,女,34岁,讲师,河南安阳师范专科学校访问学者.
  • 基金资助:

    国家攀登计划项目

Hydrolysis and Structural Disintegration of MCM-41 Molecular Sieves

LI Hui-Yun, SUN Yu, YUE Ying-Hong, GAO Zi   

  1. Department of Chemistry, Fudan University, Shanghai, 200433
  • Received:1998-03-10 Online:1999-02-24 Published:1999-02-24

摘要: 详细考察了SiMCM-41、AlMCM-41和HAlMCM-41在不同环境中的水解和结构破坏情况.空气和水蒸汽中短期高温焙烧对全硅型SiMCM-41的结构影响较小,但在潮湿空气中长期放置可因Si-O-Si键发生水解而造成结构的严重破坏.AlMCM-41的抗水解能力优于SiMCM-41的,但因其结构中包含一定量的Na+离子,降低了高温焙烧时结构的热稳定性和水热稳定性.HAlMCM-41的热稳定性和水热稳定性均优于AlMCM-41.分子筛水热晶化过程中的盐析效应被证实是导致AlMCM-41和HAlMCM-41抗水解能力增强的原因,因此在合成原料中加盐可显著改善MCM-41分子筛的抗水解能力和稳定性.

关键词: MCM-41, 水解, 稳定性, 盐效应

Abstract: Hydrolysis and structural disintegration of SiMCM-41,AlMCM-41 and HAlMCM-41 under different conditions have been investigated. Pure SiMCM-41 exhibits a high thermal stability and hydrothermal stability when calcined in air and steam for a short period. Structural disintegration of SiMCM-41 has been observed after being exposed to moist air for 3 months, because the surface Si-O-Si bonds are split by hydrolysis forming hydrated silicic acid molecules. AlMCM-41 is more resistant to hydrolysis than SiMCM-41, but its high temperature stability in air and steam is limited by the presence of Na+ in its structure. HAlMCM-41 is more stable than AlMCM-41 during heat treatment. Salt effect during hydrothermal crystallization process has been proved to be the cause for the improvement of the stability of AlMCM-41 and HAlMCM-41 in moist air and hotwater. Hence, adding salt to the reaction mixture during hydrothermal crystallization can lead to a significant improvement of the water resistan.

Key words: MCM-41, Hydrolysis, Stability, Salt effectce and stability of MCM-41 molecular sieves.

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