Løyland Sverre, Uggerud Einar
Hylleraas Centre for Quantum Molecular Sciences, Department of Chemistry, University of Oslo, P.O. Box 1033, Blindern 0315 Oslo, Norway.
J Phys Chem A. 2024 Dec 12;128(49):10465-10473. doi: 10.1021/acs.jpca.4c03722. Epub 2024 Nov 25.
Reactions between protonated hydrogen peroxide and benzene (and benzene-) have been studied in the gas phase using an FT-ICR mass spectrometer. Four competing paths for the bimolecular system were identified, namely, proton transfer, hydride abstraction, dissociative single-electron transfer, and an electrophilic addition of HO to give the Wheland intermediate [CH, OH] followed by a subsequent elimination of water. The three latter pathways correspond to three different ways to oxidize benzene. All reaction mechanisms have been modeled using quantum chemical methods, and the calculations are in agreement with the experimental observations. The total reaction rate proceeds at collision rate (slightly higher than the calculated Langevin capture rate), which exemplifies the high reactivity of HO toward arenes. These observations demonstrate a much richer chemical landscape than previously inferred from the corresponding condensed phase reaction, where only electrophilic substitution by solvated HO was described.
利用傅里叶变换离子回旋共振质谱仪在气相中研究了质子化过氧化氢与苯（以及苯阴离子）之间的反应。确定了双分子体系的四条竞争路径，即质子转移、氢化物夺取、解离单电子转移以及HO的亲电加成生成惠兰中间体[CH, OH]，随后消除水。后三条路径对应于氧化苯的三种不同方式。所有反应机理均采用量子化学方法进行了模拟，计算结果与实验观测结果一致。总反应速率以碰撞速率进行（略高于计算得到的朗之万捕获速率），这体现了HO对芳烃的高反应活性。这些观察结果表明，化学图景比之前从相应凝聚相反应中推断的要丰富得多，在凝聚相反应中仅描述了溶剂化HO的亲电取代反应。
