物理化学学报 >> 2004, Vol. 20 >> Issue (05): 535-539.doi: 10.3866/PKU.WHXB20040518

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NCO自由基与SO2、CS2反应的速率常数

张智强;胡长进;裴林森;陈从香;陈旸   

  1. 中国科学院选键化学重点实验室,中国科技大学化学物理系,合肥　230026
  • 收稿日期:2003-11-12 修回日期:2004-01-27 发布日期:2004-05-15
  • 通讯作者: 陈旸 E-mail:yangchen@ustc.edu.cn

The Rate Constants of the Reactions of NCO with SO2 or CS2

Zhang Zhi-Qiang;Hu Chang-Jin;Pei Lin-Sen;Chen Cong-Xiang;Chen Yang   

  1. Laboratory of Bond Selective Chemistry, Department of Chemical Physics, University of Science and Technology of China, Hefei　230026
  • Received:2003-11-12 Revised:2004-01-27 Published:2004-05-15
  • Contact: Chen Yang E-mail:yangchen@ustc.edu.cn

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摘要： 利用波长为266 nm的激光光解CHBr3产生CH自由基,其与NO反应作为NCO自由基的来源.在298 K,总压2660 Pa的条件下,采用激光诱导荧光的方法,研究了NCO自由基与SO2、CS2的反应.得到了NCO自由基与SO2、CS2双分子反应速率常数分别为（1.8±0.3）×10－11和（3.1±0.4）×10－12 cm3•molecule－1•s－1.对这两个反应在B3LYP/6-31＋G(d)的水平上进行理论研究的结果表明,NCO自由基与SO2、CS2的反应是加成反应,其机理是NCO自由基中的N原子攻击反应物的中心原子,得到加成产物.

关键词: NCO自由基, 激光光解-激光诱导荧光（LP－LIF）, 反应速率常数

Abstract: The reactions of NCO with SO2 or CS2 in gas phase under total pressure of 2660 Pa and 298 K were studied by laser photolysis/laser induced fluorescence (LP/LIF).The NCO radicals were produced by laser photolysis of CHBr3 at 266 nm followed by the reaction of the produced CH in the photolysis reaction with NO. The relative concentration of ground states NCO radicals were monitored by time resolved LIF spectra. From the results of time resolved measurements on the NCO radicals, the bimolecular rate constants for the reactions of NCO with SO2 and CS2 were obtained as (1.8±0.3)×10－11 and (3.1±0.4)×10－12 cm3•molecule－1•s－1, respectively. In addition, the two reactions were studied using ab initio calculations at the B3LYP/6-31＋G(d) level. The results show that both are addition reactions and have the similar mechanism in which N atom of NCO radical attacks the central atom of SO2 or CS2 to form addition product.

Key words: NCO radical, Laser photolysis-laser induced florescence(LP-LIF), Rate constant of reaction