標題: Selective catalytic oxidation of benzene to phenol by a vanadium oxide nanorod (V-nr) catalyst in CH3CN using H2O2(aq) and pyrazine-2-carboxylic acid (PCA)
作者: Wanna, Wondemagegn Hailemichael
Janmanchi, Damodar
Thiyagarajan, Natarajan
Ramu, Ravirala
Tsai, Yi-Fang
Pao, Chih-Wen
Yu, Steve S. -F.
交大名義發表
National Chiao Tung University
公開日期: 7-十二月-2019
摘要: Vanadium based catalysts are known to be highly efficient for oxidation reactions using O-2 and/or H2O2. In this study, we developed a vanadium catalyst that can be prepared by a reaction of VCl3 in acetonitrile with the addition of 35% hydrogen peroxide (H2O2). The catalyst was further characterized by a variety of methods including V-51 NMR, XRD, XPS, XAS, EA, ICP-AES, BET, SEM and TEM. Based on the results obtained, the catalyst was identified as a vanadium oxide material (V-nr) with the morphology and shape of a nanorod with dimensions of similar to 40 nm x 450 nm (width x length). The porosity of a material can be essential for small molecule activation on a heterogeneous surface. This material exhibits exceptional catalytic performance for the selective oxidation of benzene to phenol (PhOH) at room temperature using H2O2 as an oxidant in acetonitrile. The addition of pyrazine-2-carboxylic acid (PCA) as a co-catalyst can efficiently enhance the catalytic activity with a percentage selectivity of 87-99% phenol, producing p-benzoquinone (p-BQ) as a minor product. With the deployment of (H2O2)-O-18, we observed the product phenol to be highly enriched by O-18, indicating that the hydroperoxovanadium intermediate is essential for its catalytic conversion. Together with its high NIH shift ratio (80% deuterium remained) observed with the mechanistic probe of 4-[H-2(0,1)] toluene, the results suggested that the catalytic oxidation reaction mediated by Vnr may involve metal based oxygenated intermediates for its highly selective catalytic oxidation of benzene to phenol.
URI: http://dx.doi.org/10.1039/c9nj02514f
http://hdl.handle.net/11536/153597
ISSN: 1144-0546
DOI: 10.1039/c9nj02514f
期刊: NEW JOURNAL OF CHEMISTRY
Volume: 43
Issue: 45
起始頁: 17819
結束頁: 17830
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