乙腈溶液中NO_3自由基与联苯的反应机理  

Reaction Mechanism of the Nitrate Radical with Biphenyl in Acetonitrile

作　　者：董文博[1] 朱承驻[1] 房豪杰[1] 欧阳彬[1] 张仁熙[1] 侯惠奇[1] 

机构地区：[1]复旦大学环境科学研究所,上海200433

出　　处：《化学学报》2005年第23期2147-2152,共6页Acta Chimica Sinica

基　　金：国家自然科学基金(No.20377009)资助项目.

摘　　要：以硝酸铈铵乙腈溶液激光闪光光解产生的NO_3自由基在无氧条件下与联苯作用,采用瞬态光谱技术和GC-MS技术分别对反应过程中产生的中间瞬态产物以及反应的最终产物进行了分析,对反应历程作了明确推断.研究表明,NO3自由基首先从联苯的苯环上夺取电子形成电荷转移复合物,二级反应速率常数为8.24×10~9L·mol^(-1)·s^(-1);进而通过消除反应在苯环上定位形成邻-硝基联苯和对-硝基联苯,电荷转移复合物衰减表观的一级反应速率常数为2.30×105s^(-1).NO3 radical produced in the laser flash photolysis of cerium ammonium nitrate was applied to attack biphenyl in oxygen-free acetonitrile solution. The transient intermediates were identified with the nanosecond transient spectroscopic analysis and the fmal products were detected by GC-MS technique. A reasonable mechanism of the reaction was proposed. With a second-order rate constant of 8.24×10^9 L·mol^-1,s^-1, NO3 radical withdrew an electron from the biphenyl molecule to produce a charge-transfer （C-T） complex, which was sequentially transformed to ο- or ρ-nitrobiphenyl by eliminhtion of a hydroxyl radical. The total first-order decay rate constant of the C-T complex was determined to be 2.30×10^5 s^-1.

关 键 词：激光闪光光解 瞬态吸收光谱 联苯 NO3自由基 电荷转移复合物 

分 类 号：O621.25[理学—有机化学]