含有基原子的终端基的高效环氧化:在Cu{111}上转甲基 styrene
Rachael L Cropley1, Federico J Williams, Andrew J Urquhart
1Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK.
Journal of the American Chemical Society
|April 21, 2005
概括
在Cu{111}上选择性氧化转甲基styrene产生一个环氧化物. 表面氧原子的排列决定了环氧化效率,孤立的原子促进了反应.
科学领域:
- 表面化学 表面化学
- 不同质的催化剂.
- 有机氧化的有机氧化.
背景情况:
- 转甲基 styrene 具有反应性基原子,使其选择性氧化成为一个关键的挑战.
- 铜单晶,特别是,是氧化反应的广泛研究的催化剂.
研究的目的:
- 为了研究在Cu{111}表面上转甲基烯的选择性氧化.
- 阐明表面氧物种和反应剂吸附顺序对环氧化选择性的作用.
主要方法:
- 质谱仪用于检测气态产品.
- 同步快速X射线光电子光谱 (XPS) 用于监测表面物种的进化.
- 近边缘X射线吸收细结构 (NEXAFS) 用于确定吸附物结构.
主要成果:
- 实现了转甲基 styrene 到其环氧化物的有效部分氧化.
- 氧化选择性对反应物的吸附顺序高度敏感.
- 表面上孤立的氧原子有利于环氧化,而氧岛则没有.
- 吸附的转甲基styrene采用一个平面的方向与表面附近的酸.
结论:
- 酸抽象是限制环氧化选择性的关键因素.
- 氧原子的空间分布显著影响反应路径和产品选择性.
- 提出了一种反应机制,将表面结构和反应性关联起来.
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