Preparation and Characterization of Vanadium Oxide Species Supported on Mesoporous Silica for the Hydroxylation of Benzene
Preparation and Characterization of Vanadium Oxide Species Supported on Mesoporous Silica for the Hydroxylation of Benzene
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DOI：
10.1021/jp066323k
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发表时间：
2007-02
影响因子：
3.7
通讯作者：
Chia-Hung Lee;T. Lin;C. Mou
中科院分区：
文献类型：
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作者：
Chia-Hung Lee;T. Lin;C. Mou
在60°C的乙腈溶剂中，采用铝取代介孔二氧化硅（Al-MPS）负载的VOx催化剂和过氧化氢作为氧化剂，进行了苯的均相液相直接催化氧化制苯酚。采用分子设计分散法制备了Al-MPS负载型VOx催化剂。单层VO(acac)2配合物（acac：乙酰丙酮酸）的沉积可以通过氢键或配体交换机制实现，随后有机acac配体在氧气气氛中高温分解，得到VV中心的六配位。八面体氧化钒样品在催化中心周围具有许多可移动的配体（即H2O或溶剂），这些配体很容易被过氧化氢取代，从而产生苯羟基化的活性过氧中间体。从粉末x射线衍射、N2吸附和解吸等温线、UV - vis漫反射和电子透射等方面进行了研究。
The homogeneous liquid-phase direct catalytic oxidation of benzene to phenol was performed at 60 °C in acetonitrile solvent using various catalysts of VOx supported on aluminum-substituted mesoporous silica (Al-MPS) and hydrogen peroxide as the oxidant. We employed the molecular designed dispersion method to prepare the VOx catalyst supported on Al-MPS. The deposit of monolayer VO(acac)2 complexes (acac: acetylacetonate) could be achieved by hydrogen bonding or a ligand-exchange mechanism and subsequently decomposition of organic acac ligands in an oxygen atmosphere at elevated temperature, yielding the six coordination of VV center. The octahedral vanadium oxide samples possess much mobile ligands (i.e., H2O or solvent) around the catalytic center that could be easily substituted by hydrogen peroxide and yielded the active peroxo intermediate for the hydroxylation of benzene. From the studies of powder X-ray diffraction, N2 adsorption and desorption isotherms, diffuse reflectance UV−vis, and electron pa...