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化学学报
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化学学报 ›› 2006, Vol. 64 ›› Issue (6): 483-488. 上一篇    下一篇

研究论文

[Me3NC2H4OH]Zn2Cl5水溶液的激光光解研究

付海英，吴国忠，龙德武，刘耀东，王文峰，姚思德*   

  1. (中国科学院上海应用物理研究所 上海 201800)
  • 投稿日期:2005-06-21 修回日期:2005-12-05 发布日期:2006-03-28
  • 通讯作者: 姚思德

Studies of [Me3NC2H4OH]Zn2Cl5 Aqueous Solution by Laser Photolysis

FU Hai-Ying, WU Guo-Zhong, LONG De-Wu, LIU Yao-Dong, WANG Wen-Feng, YAO Si-De*   

  1. (Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800)
  • Received:2005-06-21 Revised:2005-12-05 Published:2006-03-28
  • Contact: YAO Si-De

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利用时间分辨激光光解技术研究了季铵盐型离子液体[Me3NC2H4OH]Zn2Cl5(简写R-Zn2Cl5)的光解行为, 研究发现离子液体能被266 nm激光单光子电离, 生成阳离子自由基、[Zn2Cl5]•中性自由基和水合电子, 观察到胆碱激发三线态的存在, 并测定了离子液体光电离的量子产额为0.04. 利用266 nm激光对离子液体、胆碱、氯化锌、氯化钠的光解行为比较, 发现胆碱阳离子的贡献很小, [Zn2Cl5]－阴离子起主要作用. 采用氧化性自由基SO4•－引发离子自由基, 揭示其光电离机理, 测定离子液体的动力学反应速率常数, SO4•－ 460 nm的衰减速率常数为1.3×109 L•mol－1•s－1, 320 nm离子自由基瞬态产物的生成速率常数为1.5×109 L•mol－1•s－1, 两者很接近, 说明SO4•－自由基的衰减与瞬态自由基的生成是同步的.

关键词: 离子液体, 胆碱, 单光子电离, 激光光解

The absorption spectra of [Me3NC2H4OH]Zn2Cl5 (R-Zn2Cl5) in aqueous solutions were studied by time-resolved laser photolysis, and the mechanism of monophotonic ionization was suggested. The oxidizing radical SO4•－ was used to produce radical cation. Comparison of R-Zn2Cl5 with NaCl, ZnCl2 and choline showed that [Zn2Cl5]－ played an important role in photoionization while [Me3NC2H4OH]•＋ cation had little function on its photolysis. Rate constant for oxidation reactions was determined in R-Zn2Cl5 ionic liquid. The second-order decay rate constant of SO4•－ oxidation reactions at 460 nm, 1.3×109 L•mol－1•s－1, was almost equal to the product rate constant of 1.5×109 L•mol－1•s－1 at 320 nm in R-Zn2Cl5 aqueous solution, showing that the decay and the product were synchronic.

Key words: ionic liquid, choline, monophotonic ionization, laser photolysis