物理化学学报 >> 2014, Vol. 30 >> Issue (5): 797-802.doi: 10.3866/PKU.WHXB201403072

热力学,动力学和结构化学 上一篇    下一篇

C2a3Пu)自由基与含硫小分子反应的温度效应

胡仁志1, 谢品华1, 张群2, 司福祺1, 陈旸2   

  1. 1 中国科学院安徽光学精密机械研究所, 中国科学院环境光学与技术重点实验室, 合肥230031;
    2 中国科学技术大学化学物理系, 合肥微尺度物质科学国家实验室, 合肥230026
  • 收稿日期:2013-12-31 修回日期:2014-03-07 发布日期:2014-04-25
  • 通讯作者: 胡仁志,陈旸 E-mail:rzhu@aiofm.ac.cn;yangchen@ustc.edu.cn
  • 基金资助:

    国家自然科学基金(61108031,21173205),国家重点基础研究发展规划项目(973)(2010CB923302)及中国科学院知识创新工程(KJCX2-YWN24)资助项目

Temperature Dependence of C2(a3Пu) Radical Reactions with Sulfur Bearing Molecules

HU Ren-Zhi1, XIE Pin-Hua1, ZHANG Qun2, SI Fu-Qi1, CHEN Yang2   

  1. 1 Key Laboratory of Environmental Optics & Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Science, Hefei 230031, P. R. China;
    2 Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, P. R. China
  • Received:2013-12-31 Revised:2014-03-07 Published:2014-04-25
  • Contact: HU Ren-Zhi, CHEN Yang E-mail:rzhu@aiofm.ac.cn;yangchen@ustc.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (61108031, 21173205), National Key Basic Research Program of China (973) (2010CB923302), and Knowledge Innovation Programs of the Chinese Academy of Sciences (KJCX2-YW-N24).

摘要:

运用脉冲激光光解-激光诱导荧光(PLP-LIF)的方法在298-673 K的温度范围内测量了C2a3Пu)自由基与含硫小分子(H2S,SO2,CS2)气相反应的双分子反应速率常数. 获得的速率常数可以用Arrhenius 公式表达如下(单位:cm3·molecule-1·s-1):k(H2S)=(1.61±0.06)×10-12exp[-(180.91±15.73)/T],k(SO2)=(1.26±0.10)×10-15×exp[(2230.68±27.77)/T],k(CS2)=(1.17±0.02)×10-10 exp[(253.31±7.69)/T];误差为2σ. 由获得的双分子速率常数及所表现的正温度效应,认为C2a3Пu)与H2S反应遵循抽氢反应机理;C2a3Пu与SO2反应是无能垒的过程,反应速率表现出强的负温度依赖关系;根据较大的双分子速率常数及其呈现的负温度效应我们认为,C2a3Пu与CS2反应遵循加成反应机理.

关键词: C2a3Пu)自由基, 激光诱导荧光, 速率常数, 温度效应

Abstract:

The bimolecular rate constants for the gas- phase reactions of C2(a3Пu) with sulfur-bearing molecules (H2S, SO2, CS2) were measured over the temperature range 298-673 K, by means of pulsed laser photolysis/laser-induced fluorescence technique. The rate constants (cm3·molecule-1·s-1) can be fitted by the normal Arrhenius expressions: k(H2S)=(1.61±0.06)×10-12exp[-(180.91±15.73)/T], k(SO2)=(1.26±0.10)×10-15 exp[(2230.68±27.77)/T], k(CS2)=(1.17±0.02)×10-10 exp[(253.31±7.69)/T], where all error estimates are ±2σ and represent the precision of the fit. The observed bimolecular rate constants and positive temperature dependence of k(H2S) show that the reaction of C2(a3Пu) with H2S in the range 298-673 K proceeds via a hydrogen-abstraction mechanism. The bimolecular rate constants for the reaction of C2(a3Пu) with SO2 show a strong negative temperature dependence. The high rate constants for the C2(a3Пu)+CS2 reaction and negative temperature dependence support an addition mechanism.

Key words: C2(a3Пu) radical, Laser induced fluorescence, Rate constant, Temperature dependence

MSC2000: 

  • O643