氯代烃光解活泼自由基的ESR研究

本文用2,4-二硝基苯亚甲基特丁基氮氧化物(DNPBN)作自由基捕捉剂研究了氯代烃光解过程产生的自由基中间体。实验结果表明在汞灯照射下键能较低的多氯代烷烃分子中的碳-氯键极易发生均裂而产生碳中心自由基与活泼的氯原子, 并且后者可被DNPBN捕获, 形成颇为稳定的氮氧自由基加合物Cl-DNPBN]~·。对多氯代苯,随着取代氯原子数目增多, 加合物Cl-DNPBN]~·的ESR信号强度也明显增加。此外, DNPBN对氯原子的大量捕捉实验还证明它对氯原子是一种高效的特征捕捉剂。

ESR STUDY ON THE PHOTOLYSIS OF CHLOROHYDROCARBONS

A new kind of nitrone, 2, 4,-dinitrophenyl-t-butyl nitrone (DNPBN), has been used for investigating the photolytic mechanism of chlorohydroearbon and trapping active chlorine atom and other C-centre radicals produced therein. The results show that under the irradiation of high-pressure mercury lamp, for polychlorohydrocarbon, the more the substitute chlorine atom, the easier the homolysis of C—Cl bond of its and seldem chlorine can be trapped from mono- or dichlorohydrocarbons. On the other hand, both chlorine, a more persistent adduct (Cl—DNPBN)~· than other famillar adducts, such as (Cl—PBN)~·, can be obtained.