Grafted Polymethylhydrosiloxane on Hierarchically Porous Silica Monoliths: A New Path to Monolith-Supported Palladium Nanoparticles for Continuous Flow Catalysis Applications

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• 作者：Carl-Hugo PélissonTakahiro Nakanishi ; Yang Zhu ; Kei Morisato ; Toshiyuki Kamei ; Ayaka Maeno ; Hironori Kaji ; Shunki Muroyama ; Masamoto Tafu ; Kazuyoshi Kanamori ; Toyoshi ShimadaKazuki Nakanishi
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2017
• 出版时间：January 11, 2017
• 年：2017
• 卷：9
• 期：1
• 页码：406-412
• 全文大小：442K
• ISSN：1944-8252

文摘

Polymethylhydrosiloxane has been grafted on the surface of a hierarchically porous silica monolith using a facile catalytic reaction between Si–H and silanol to anchor the polymer. This easy methodology leads to the functionalization of the surface of a silica monolith, where a large amount of free Si–H bonds remain available for reducing metal ions in solution. Palladium nanoparticles of 15 nm have been synthesized homogeneously inside the mesopores of the monolith without any stabilizers, using a flow of a solution containing Pd²⁺. This monolith was used as column-type fixed bed catalyst for continuous flow hydrogenation of styrene and selective hydrogenation of 3-hexyn-1-ol, in each case without a significant decrease of the catalytic activity after several hours or days. Conversion, selectivity, and stereoselectivity of the alkyne hydrogenation can be tuned by flow rates of hydrogen and the substrate solution, leading to high productivity (1.57 mol g(Pd)⁻¹ h^–1) of the corresponding cis-alkene.