A Thorough Investigation of the Active Titanium Species in TS-1 Zeolite by In Situ UV Resonance Raman Spectroscopy
A Thorough Investigation of the Active Titanium Species in TS-1 Zeolite by In Situ UV Resonance Raman Spectroscopy
复制标题
通过原位紫外共振拉曼光谱对 TS-1 沸石中的活性钛物质进行彻底研究
DOI：
10.1002/chem.201201319
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发表时间：
2012-10-01
影响因子：
4.3
通讯作者：
Li, Can
中科院分区：
文献类型：
--
作者：
Guo, Qiang;Sun, Keju;Li, Can
通过原位紫外共振拉曼光谱结合紫外/可见漫反射光谱、DFT 计算和环氧化实验，对 TS-1 沸石中的活性钛物质进行了彻底研究。当在 266 nm 激光线激发时，一种新的钛物质在 695 cm-1 处具有特征拉曼谱带。结果表明，除了四面体配位的钛物质外，新发现的钛物质在环氧化反应中也很活跃。然而，新钛物质的酸性可以催化环氧产物的开环反应。相对于四面体配位的钛物质，它导致对环氧产物的选择性较低。通过添加弱碱性试剂可以抑制副反应。
A thorough investigation of the active titanium species in TS-1 zeolite was conducted by in situ UV resonance Raman spectroscopy combined with UV/Vis diffuse reflectance spectroscopy, DFT calculations, and epoxidation experiments. A new titanium species was identified with a characteristic Raman band at 695 cm-1 when excited at the 266 nm laser line. It is shown that the newly found titanium species is active in the epoxidation reactions in addition to the tetrahedrally coordinated titanium species. However, the acidity of the new titanium species could catalyze the ring-opening reactions of the epoxy products. It results in a lower selectivity toward the epoxy products relative to that of the tetrahedrally coordinated titanium species. The side reaction can be suppressed by the addition of a weak basic reagent.