物理化学学报 >> 2007, Vol. 23 >> Issue (11): 1677-1682.doi: 10.1016/S1872-1508(07)60081-3

研究论文 上一篇    下一篇

355 nm光诱发的水体中HNO2与C6H5Br交叉反应机理

秦艳; 黄丽; 董文博; 房豪杰; 侯惠奇   

  1. 复旦大学环境科学研究所, 上海 200433; 东华大学环境科学与工程学院, 上海 200051
  • 收稿日期:2007-06-14 修回日期:2007-07-06 发布日期:2007-11-01
  • 通讯作者: 侯惠奇 E-mail:fdesi@fudan.edu.cn

Cross-Reaction Mechanism between HNO2 and C6H5Br in Aqueous Solution under Irradiation at 355 nm

QIN Yan; HUANG Li; DONG Wen-Bo; FANG Hao-Jie; HOU Hui-Qi   

  1. Institute of Environmental Science, Fudan University, Shanghai 200433, P. R. China; College of Environmental Science and Engineering, Donghua University, Shanghai 200051, P. R. China
  • Received:2007-06-14 Revised:2007-07-06 Published:2007-11-01
  • Contact: HOU Hui-Qi E-mail:fdesi@fudan.edu.cn

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摘要： 利用激光闪光光解技术研究了有氧、无氧条件下HNO2-C6H5Br-H2O体系的光化学反应. 研究结果表明, HNO2与C6H5Br的光化学反应由HNO2光解产生·OH自由基引发, ·OH与C6H5Br反应生成C6H5Br…OH, 反应速率常数为(8.1±0.7)×109 L·mol-1·s-1. C6H5Br…OH可被HNO2或O2氧化. C6H5Br…OH 与HNO2的二级反应速率常数为(3.0±0.5)×107 L·mol-1·s-1, 比C6H5Br…OH与O2的反应速率常数(4.0±0.6)×108 L·mol-1·s-1小, C6H5Br…OH与O2生成的C6H5Br…OHO2以(2.4±0.1)×104 s-1 的速率单分子衰减. 气相色谱-质谱联用(GC-MS)分析表明, C6H5Br…OH 与HNO2或O2作用可形成多种含硝基的化合物或醌类物质.

关键词: 溴苯, 激光闪光光解, HNO2, 瞬态吸收光谱, ·OH 自由基, 交叉反应

Abstract: The reaction mechanism between HNO2 and C6H5Br in aqueous solution in the presence or absence of O2 was studied using laser flash photolysis transient absorption spectrum technique under irradiation at 355 nm. The experimental results suggested the generation of·OH radical through the photolysis of HNO2. The addition of·OH radical to bromobenzene to form an OH-adduct, C6H5Br…OH, involved a second-order rate constant of (8.1±0.7)×109 L·mol-1·s-1 C6H5Br…OHcould be oxidized by O2 or HNO2. The second-order rate constant (3.0±0.5)×107 L·mol-1·s-1 for the reaction of C6H5Br…OHwith HNO2was much slower than (4.0±0.6)×108 L·mol-1·s-1 for the reaction of C6H5Br…OH with O2. The decay constant of C6H5Br…OHO2 produced by the reaction of C6H5Br…OH with O2 decayed was (2.4±0.1)×104 s-1. Gas chromatography and mass spectrometric (GC-MS) analysis suggested the formation of multiple compounds containing nitryl or quinone formed by the reaction of C6H5Br…OH with HNO2 or O2.

Key words: Bromobenzene, Laser flash photolysis, HNO2, Transient absorbance spectrum, ·OH radical, Cross-reaction