Synergistic Catalysis by Lewis Acid and Base Sites on ZrO2 for Meerwein鈥揚onndorf鈥揤erley Reduction

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• 作者：Tasuku Komanoya ; Kiyotaka Nakajima ; Masaaki Kitano ; Michikazu Hara
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：November 25, 2015
• 年：2015
• 卷：119
• 期：47
• 页码：26540-26546
• 全文大小：376K
• ISSN：1932-7455

文摘

Early transition metal oxides, TiO₂, ZrO₂, and Nb₂O₅, were studied as heterogeneous catalysts for the Meerwein鈥揚onndorf鈥揤erley (MPV) reduction of cyclohexanone in 2-propanol. Despite a small amount of Lewis acid sites and weak Lewis acid strength, ZrO₂ was clearly superior to TiO₂ and Nb₂O₅ with respect to reaction rate. Fourier transform infrared spectroscopy (FT-IR) and temperature-programmed-desorption (TPD) measurements revealed that ZrO₂ has large amounts of base sites that activate the methylene groups in 2-propanol bonded to Lewis acid sites. Various analyses, including experiments using isotopic 2-propanol, suggest that efficient MPV reduction over ZrO₂ is due not only to Lewis acid strength and density, but also to a synergistic effect of base and Lewis acid sites.