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化学学报
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化学学报 ›› 1999, Vol. 57 ›› Issue (9): 1014-1021. 上一篇    下一篇

研究论文

MCM-41分子筛的改性、表面结构与吸附性质的研究

龙英才;许太明;董维阳;孙尧俊   

  1. 复旦大学化学系.上海(200433);复旦大学分析测试中心.上海(200433)
  • 发布日期:1999-09-15

Studies on the modification, surface structure and adsorption of MCM- 41 mesoporous molecular sieve

Long Yingcai;Xu Taiming;Dong Weiyang;Sun Yaojun   

  1. Fudan Univ, Dept Chem.Shanghai(200433);Fudan Univ, Ctr Anal & Measurement.Shanghai(200433)
  • Published:1999-09-15

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573

被引次数

69 | 1

用三甲基氯硅烷、二甲基二氯硅烷、甲基三氯硅烷、四氯化硅与甲基碘改性高硅MCM-41中孔分子筛。XRD,^2^9SiMASNMR,^1^3CMASNMR,以及N~2、水与环己烷吸附的表征,显示改性不同程度地改变了分子筛的表面组成与结构,减小孔径,增加孔壁厚度,因而影响吸附行为,减小吸附容量。硅烷化减少了MCM-41的表面硅羟基含量,增加其疏水性。用CH~3I改性使孔径减小1.4nm,而硅羟基含量并未显著减少。硅烷化以及用CH~3I改性可提高MCM-41分子筛的热稳定性。SiCl~4的改性作用相对不明显。样品的水及环己烷吸附容量与其表面硅羟基含量呈现不同的线性关系,揭示高硅MCM-41分子筛表面吸附中心的本性。

关键词: 固体核磁, 核磁共振谱法, 高硅分子筛, 改性, 表面结构, 吸附, MCM-41, 孔径分布, 氯硅烷, 碘甲烷

High silica MCM-41 and modified samples were characterized in detail with XRD, ^2^9Si and ^1^3C CP MAS NMR, and adsorption isotherms of nitrogen, water and cyclo-hexane. The modification reagents used were trimethylchlorosilane, dimethyldichlorosilane, methyltrichlorosilane, silicon tetrachloride and methyliodide. The modification greatly varies the surface structure, decreases the pore diameter, and increases the wall thickness. A linear relationship between the contents of silanol groups and the amounts of water and cyclohexane absorbed reveals the nature of adsorption centers in the samples.

Key words: NMR SPECTROMETRY, MODIFICATION, SURFACE STRUCTURE, ADSORPTION, PORE SIZE DISTRIBUTION, CHLOROSILANE, IODOMETHANE

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