物理化学学报 >> 2004, Vol. 20 >> Issue (09): 1099-1103.doi: 10.3866/PKU.WHXB20040908

研究论文 上一篇    下一篇

CCl4的光解微观机制研究

潘丹霞;于勇;董文博;郑璐;卢霄;姚思德;侯惠奇   

  1. 复旦大学环境科学研究所,上海 200433; 中国科学院上海应用物理研究所,上海 201800
  • 收稿日期:2004-01-05 修回日期:2004-05-01 发布日期:2004-09-15
  • 通讯作者: 侯惠奇 E-mail:fdesi@fudan.edu.cn

Study On the Laser Flash Photolysis of Carbon Tetrachloride

Pan Dan-Xia;Yu Yong;Dong Wen-Bo;Zheng Lu;Lu Xiao;Yao Si-De;Hou Hui-Qi   

  1. Institute of Environment Science, Fudan University, Shanghai 200433; 1Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800
  • Received:2004-01-05 Revised:2004-05-01 Published:2004-09-15
  • Contact: Hou Hui-Qi E-mail:fdesi@fudan.edu.cn

摘要: 利用激光光解瞬态吸收光谱技术,研究有氧和无氧条件下CCl4的激光光解.结果表明,在248 nm激光作用下, CCl4发生了单光子吸收,反应生成{CCl4-Cl}σ电荷转移复合物、(CCl3+…Cl-)离子对、CCl3O2过氧自由基等瞬态物种,它们的衰减过程是表观一级反应. {CCl4-Cl}σ电荷转移复合物在有氧/无氧条件下的拟合衰减速率常数分别是3.38×106 s-1和3.65×106 s-1,它的形成不受氧气含量影响. (CCl3+…Cl-)离子对在有氧/无氧条件下的拟合衰减速率分别为3.73×107 s-1和3.02×107 s-1,它的形成也不受氧气含量影响, CCl3O2过氧自由基需在有氧条件下形成,拟合衰减速率是2.32×104 s-1.

关键词: 激光光解, 四氯化碳, 闪光, 瞬态物种, 自由基

Abstract: Carbon tetrachloride was subjected to transient laser flash photolysis in the presence or absence of oxygen, transient absorption spectra were observed and analyzed. The experiment indicates that a series of micro-reactions occurred under 248 nm laser by a single photon absorption of CCl4, including the dissociation of the solvent and the formation of sophisticated substances-{CCl4-Cl}σ charge transfer complex,( CCl3+…Cl-) ion pair and CCl3O2. These absorptions decay according to the first order kinetics, and the decay rate constants of {CCl4-Cl}σ charge transfer complex were obtained to be 3.38×106 s-1 and 3.65×106 s-1 in the presence and absence of oxygen, respectively, and its production has nothing to do with the oxygen. The decay rate constants of (CCl3+…Cl-) were also gained to be 3.73×107 s-1 and 3.02×107 s-1 in the presence and absent of oxygen, respectively. However, CCl3O2 exists only in the presence of oxygen with a decay rate constant of 2.32×104 s-1.

Key words: Laser photolysis, Carbon tetrachloride, Flash, Transient substance,  Free radical