The Influence of Surface Modification on the Epoxidation Selectivity and Mechanism of TiSBA15 and TaSBA15 Catalysts with Aqueous Hydrogen Peroxide
The Influence of Surface Modification on the Epoxidation Selectivity and Mechanism of TiSBA15 and TaSBA15 Catalysts with Aqueous Hydrogen Peroxide
复制标题
表面改性对TiSBA15和TaSBA15催化剂水性过氧化氢环氧化选择性及机理的影响
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
T. Tilley
中科院分区：
文献类型：
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作者：
Daniel A. Ruddy;R. Brutchey;T. Tilley
采用热释电分子前体法在介孔SBA 15载体表面引入Ti（IV）和Ta（V）中心。用一系列（N，N-二甲基氨基）三烷基硅烷Me 2NSiMe 2 R（其中R = Me、nBu或nOc）修饰所得表面SiOH、TiOH和TaOH位点。与未改性的催化剂相比，表面改性的催化剂在环己烯与H2 O2的环氧化反应中具有更高的活性，并且表现出显著更高的氧化环己烯的选择性（对于Ti（IV）高达58%，对于Ta（V）大于95%）。使用原位光谱来探测这种现象，并且确定了双端封端的Ti（IV）或Ta（V）位点对于实现高环氧化物选择性是必不可少的。
The thermolytic molecular precursor method was used to introduce site-isolated Ti(IV) and Ta(V) centers onto the surface of a mesoporous SBA15 support. The resulting surface SiOH, TiOH, and TaOH sites were modified with a series of (N,N-dimethylamino)trialkylsilanes, Me2NSiMe2R (where R = Me, nBu, or nOc). Compared to the unmodified catalysts, the surface-modified catalysts are more active in the epoxidation of cyclohexene with H2O2 and exhibit a markedly greater selectivity for cyclohexene oxide (up to 58% for Ti(IV) and greater than 95% for Ta(V)). In situ spectroscopies were used to probe this phenomenon, and it was determined that a siloxy-capped Ti(IV) or Ta(V) site is essential to achieve the high epoxide selectivity.