Direct silylation of a mesostructured precursor for novel mesoporous silica KSW-2

Tetsuro Shigeno, Masatsune Nagao, Tatsuo Kimura, Kazuyuki Kuroda

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    Abstract

    A mesostructured precursor for KSW-2 with semi-squared mesopores was directly modified with chlorotrimethylsilane and chlorooctyldimethylsilane for the first time. The silylated products were characterized by powder XRD, IR, 29Si MAS NMR, CHN analysis, and N2 and water vapor adsorption measurements. Mesoporous silica KSW-2 prepared by calcination of the precursor was also silylated in a similar manner. The mesostructures of the precursor and of KSW-2 were retained after silylation. The characteristics of semi-squared mesopores remarkably changed; the hydrophobicity of the derivatives increased substantially after silylation. The BET surface area, the pore volume, and the width of the semi-squared mesopores decreased after silylation, and the degree of the decrease is larger for the octyldimethylsilyl derivatives than that for the trimethylsilyl derivatives. The numbers of the silyl groups grafted on the directly silylated derivatives are larger than those on the silylated KSW-2. In addition, calcination of the trimethylsilylated products yielded mesoporous silica with the same structure in which the pore wall thickness was increased because of the participation of the silyl groups to the silica network by oxidation.

    Original languageEnglish
    Pages (from-to)8102-8107
    Number of pages6
    JournalLangmuir
    Volume18
    Issue number21
    DOIs
    Publication statusPublished - 2002 Oct 15

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    ASJC Scopus subject areas

    • Colloid and Surface Chemistry
    • Physical and Theoretical Chemistry

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