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化学学报
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化学学报 ›› 2007, Vol. 65 ›› Issue (5): 451-458. 上一篇    下一篇

研究论文

266 nm光照下水溶液中氯苯与H2O2的反应机理研究

朱承驻1,2, 秦艳2, 周元祥1, 董文博*,2, 侯惠奇*,2   

  1. (1合肥工业大学资源与环境工程学院 合肥 230009)
    (2复旦大学环境科学研究所 上海 200433)
  • 投稿日期:2006-07-08 修回日期:2006-10-09 发布日期:2007-03-14
  • 通讯作者: 侯惠奇

Study on the Reaction Mechanism of Chlorobenzene with Hydrogen Peroxide in Aqueous Solutions Initiated by 266 nm UV Light

ZHU Cheng-Zhu1,2; QIN Yan2; ZHOU Yuan-Xiang1; DONG Wen-Bo*,2; HOU Hui-Qi*,2   

  1. (1 School of Resources & Environmental Engineering, Hefei University of Technology, Hefei 230009)
    (2 Institute of Environmental Science, Fudan University, Shanghai 200433)
  • Received:2006-07-08 Revised:2006-10-09 Published:2007-03-14
  • Contact: HOU Hui-Qi

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利用瞬态吸收光谱技术研究了不同条件下C6H5Cl与H2O2水溶液的激光闪光光解情况, 初步考察了其瞬态物种的生长和衰减等行为. 研究表明, •OH自由基和C6H5Cl反应生成C6H5Cl-OH adduct, 其反应速率常数在近中性、酸性条件下约为(5.89±0.65)×109和(7.07±0.61)×109 L•mol－1•s－1; 其衰减则符合双分子二级反应, 速率常数2k/εl＝1.1×106 s－1, 而在碱性时则为(4.34±0.51)×109 L•mol－1•s－1, 衰减呈准一级反应, 速率常数为2.11×105 s－1. 在有氧条件下, O2与C6H5Cl-OH adduct反应生成C6H5Cl-OHO2 adduct, 其反应速率常数为6.8×108 L•mol－1•s－1.

关键词: 激光闪光光解, 氯苯, H2O2, 瞬态吸收光谱, •, OH自由基

The reaction microscopic mechanism of chlorobenzene with hydrogen peroxide in aqueous solutions under different conditions was studied by laser flash photolysis. The main characteristic peaks in these transient absorbance spectra were assigned and the build-up/decay trends of several transient species were investigated. OH free radical can be produced through the 266 nm laser flash photolysis of hydrogen peroxide in aqueous solutions. The reaction of OH free radical and chlorobenzene produces C6H5Cl-OH adduct with a rate constant of (5.89±0.65)×109 (L•mol－1•s－1) in the approximately neutral solution (pH≈6) or (7.07±0.61)×109 L•mol－1•s－1 in acid (pH＝1.5) solution, while its rate constant is about (4.34±0.51)×109 L•mol－1•s－1 in the basic (pH＝9) solution. In the approximately neutral solution (pH≈6) or in acid (pH＝1.5) solution, the intermediate can decay from itself gradually through a second-order reaction with 2k/εl＝1.1×106 s－1. While in the basic (pH＝9) solution, its decay trend shows pseudo-first-order rate constant of 2.11×105 s－1. The C6H5Cl-OH adduct will be able to react with O2 to form C6H5Cl-OHO2.

Key words: laser flash photolysis, chlorobenzene, hydrogen peroxide, transient absorption spectra, •, OH radical