• Title/Summary/Keyword: Silylation Solid Base Catalyst

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Knoevenagel Condensation Reaction Using Amine-functionalized MCM-41 Base Catalysts (아민고정화 MCM-41 염기촉매를 이용한 Knoevenagel 축합반응)

  • Choi, Jung-Sik;Ahn, Wha-Seung
    • Korean Chemical Engineering Research
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    • v.44 no.4
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    • pp.417-423
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    • 2006
  • A series of amine functionalized MCM-41 catalysts were prepared by aminopropyltrimethoxysilane grafting and their catalytic performance in Knoevenagel reaction of selected substrates was investigated. Water resistant and catalytically active amine grafted MCM-41 was prepared by post-synthetic silylation using methyltrimethoxysilane ; hydrogen bonding of the water molecules formed during the condensation reaction to the active N group was suppressed, which led to high TON of the reaction. Amine functionalized MCM-41 prepared by coating method produced high conversion, but the TON of the catalyst was much lower than that of the amine grafted MCM-41; pore volume of the functionalized MCM-41 decreased substantially and large portion of the immobilized amine is believed to be hydrogen bonded to each other, which can result in decrease in the basicity of the N group. A secondary amine group was prepared by room temperature condensation between aminopropylsilane and chloropropylsilane, and the MCM-41 grafted with the secondary amine group demonstrated the highest catalytic activity among the catalysts prepared.