An efficient and recyclable copper nano-catalyst for the selective oxidation of benzene to p-benzoquinone (p-BQ) using H2O2(aq) in CH3CN

• Published in: Journal of catalysis Vol. 370; pp. 332 - 346
• Main Authors: Wanna, Wondemagegn Hailemichael, Ramu, Ravirala, Janmanchi, Damodar, Tsai, Yi-Fang, Thiyagarajan, Natarajan, Yu, Steve S.-F.
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01-02-2019
• Subjects: Benzene; Catalysis; Copper; Hydrogen peroxide; Nanoparticle; Oxidation; p-Benzoquinone; Phenol; Phenol; Hydrogen peroxide; Nanoparticle; Benzene; Oxidation; Catalysis; Copper; p-Benzoquinone
• ISSN: 0021-9517; 1090-2694
• DOI: 10.1016/j.jcat.2019.01.005

Copper nano-catalyst accumulated from [Cu(CH3CN)4ClO4] in a reaction mixture of H2O2(aq) and CH3CN can efficiently catalyze the conversion of benzene to p-benzoquinone (BQ) in high selectivity. The obtained nanoparticles can still be reused for the corresponding oxidation to maintain its high selectivity and efficiency for p-BQ production.
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•Copper nano-catalyst (Cu NC) prepared from the Cu(CH3CN)4ClO4 salt using H2O2(aq) in CH3CN.•Cu NC can efficiently oxidize benzene to p-BQ and PhOH using H2O2(aq).•High p-BQ selectivity can be achieved by tuning the composition of H2O2-H2O-CH3CN.•The Cu NC can be separated and recycled for several times.•Cu clusters in Cu NC are essential for benzene-to-p-BQ oxidation.
The molecular copper complex tetrakis(acetonitrile)copper(I) perchlorate [Cu(CH3CN)4ClO4] (1) was shown to act as a catalyst precursor for the efficient oxidation of benzene to p-benzoquinone (p-BQ) with a percentage selectivity of 60–80% under mild conditions, and produces phenol (PhOH) as a minor product at room temperature. Here, we obtained evidences showing the formation of copper based nanoparticle catalyst (NC) (2) from 1 to be the vital step responsible for its ability to catalyze the conversion of benzene to p-BQ, presumably via double oxidation. Addition of a considerable amount of H2O to the reaction mixture improved the selectivity for forming p-BQ to 84% and/or the conversion efficiency to 98%. In addition, the copper NC easily formed in situ through the oxidation of substrate using H2O2 in CH3CN. After separating the NC from the reaction mixture and recycling them several times, it still maintained comparable catalytic efficiency and selectivity for the conversion of benzene to p-BQ.