Controlling the duality of the mechanism in liquid-phase oxidation of benzyl alcohol catalysed by supported Au-Pd nanoparticles.
Controlling the duality of the mechanism in liquid-phase oxidation of benzyl alcohol catalysed by supported Au-Pd nanoparticles.
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DOI：
10.1002/chem.201003484
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发表时间：
2011-05
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影响因子：
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通讯作者：
M. Sankar;E. Nowicka;R. Tiruvalam;Qian He;S. Taylor;C. Kiely;D. Bethell;D. Knight;G. Hutchings
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文献类型：
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作者：
M. Sankar;E. Nowicka;R. Tiruvalam;Qian He;S. Taylor;C. Kiely;D. Bethell;D. Knight;G. Hutchings
在无溶剂条件下，负载型金钯纳米粒子催化氧化苯甲醇制备苯甲醛的反应中，主要产物苯甲醛的生成途径有两条。一种是苯甲醇直接被O（2）催化氧化为苯甲醛，另一种是两分子苯甲醇经反硝化反应生成等量的苯甲醛和甲苯。在此，我们报道了通过将用于负载金属纳米颗粒催化剂的金属氧化物从二氧化钛或氧化铌改变为氧化镁或氧化锌，可以关闭反硝化反应，从而完全停止甲苯的形成。据观察，与氦气气氛中的反应相比，O（2）的存在增加了该歧化反应的转换数，这意味着存在两种导致甲苯的催化途径。
In the solvent-free oxidation of benzyl alcohol to benzaldehyde using supported gold-palladium nanoparticles as catalysts, two pathways have been identified as the sources of the principal product, benzaldehyde. One is the direct catalytic oxidation of benzyl alcohol to benzaldehyde by O(2), whereas the second is the disproportionation of two molecules of benzyl alcohol to give equal amounts of benzaldehyde and toluene. Herein we report that by changing the metal oxide used to support the metal-nanoparticles catalyst from titania or niobium oxide to magnesium oxide or zinc oxide, it is possible to switch off the disproportionation reaction and thereby completely stop the toluene formation. It has been observed that the presence of O(2) increases the turnover number of this disproportionation reaction as compared to reactions in a helium atmosphere, implying that there are two catalytic pathways leading to toluene.