Characterization of acidic property of sulfo-group functionalized microporous and mesoporous silica by adsorption microcalorimetry

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• 作者：Fei-Yee Yeoh ; Akihiko Matsumoto ; Yoshiyuki Iwase ; Toshihide Baba
• 关键词：Acid site ; Adsorption microcalorimetry ; Ammonia adsorption ; Microporous silica ; Mesoporous silica ; Solid acids ; Sulfo group
• 刊名：Catalysis Today
• 出版年：2008
• 出版时间：31 March 2008
• 年：2008
• 卷：132
• 期：1-4
• 页码：46-51
• 全文大小：581 K

文摘

Sulfo-group functionalized microporous and mesoporous silica based-on a MCM-41 framework which showed solid acid property were synthesized and characterized by adsorption microcalorimetry. Both the sulfo-functionalized microporous and mesoporous silica (Micro-SO₃H and Meso-SO₃H) were prepared by the oxidation of thiol group (–SH) included mesoporous silica which was obtained through the hydrolysis and co-condensation of tetramethoxysilane (TMOS) and mercaptopropyl trimethoxysilane (MPTMS). The samples have an ordered two-dimensional hexagonal pore array similar to that of MCM-41 as depicted from the XRD patterns. Nitrogen adsorption also shows that both microporous and mesoporous silica have pore characteristics similar to MCM-41, i.e. high surface area and high pore volume. However, pore regularity, surface area and pore volume decreased as the MPTMS loading increased. Solid-state ²⁹Si NMR indicated that the sulfo groups were successfully incorporated into both microporous and mesoporous silica frameworks. This sulfo-functionalized porous silica have high NH₃ uptakes and high differential heats of NH₃ adsorption, suggesting the presence of strong acidic sulfo groups on the silica surface. Acid catalyses of the samples were characterized by the isomerization reaction of but-1-ene to cis, trans-but-2-ene.