NCO自由基与SO_2、CS_2反应的速率常数  

The Rate Constants of the Reactions of NCO with SO_2 or CS_2

作　　者：张智强[1] 胡长进[1] 裴林森[1] 陈从香[1] 陈旸[1] 

机构地区：[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

出　　处：《物理化学学报》2004年第5期535-539,共5页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金(20373065);国家重点基础研究专项基金(G1999075304);中国科学院(KJCX2-SW-H08)资助项目~~

摘　　要：利用波长为266nm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298K,总压2660Pa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)×10-12cm3·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.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/LEF). 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) x 10(-11) and (3.1 +/- 0.4) x 10(-12) cm(3 .) molecule(-1 .) s(-1), respectively. In addition, the two reactions were studied using ab initio calculations at the WLYP/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.

关 键 词：NCO自由基 SO2 CS2 速率常数常数 激光光解-激光诱导荧光技术 LP-LIF 

分 类 号：O643.131[理学—物理化学]