苯胺的脉冲辐解和激光光解研究

A PULSE RADIOLYSIS AND LASER FLASH PHOTOLYSIS STUDY OF ANILINE

用脉冲辐解与激光光解时间分辨技术 ,从瞬态方面研究了苯胺Photo -Fenton降解的可行性。研究表明 ,水溶液中苯胺可为 30 8nm的激光光电离 ,光电离的瞬态产物为阳离子自由基及脱质子后的中性自由基 ;并测得阳离子自由基脱质子转变为中性自由基的 pKa值为 7.5,以二苯甲酮为参比 ,测得苯胺光分解的量子产额极高 ( 0 .0 8)。应用脉冲辐解时间分辨技术研究了苯胺被羟基自由基降解的反应机理 ,结果表明 ,36%的羟基自由基直接进攻 -NH2 形成 NH ,54%的羟基自由基与苯胺邻位加成 ,10

Time –resolved pulse radiolysis and laser flash photolysis has been used to study the Photo-Fenton degradation of aniline. Using laser flash photolysis technique, it is demonstrated that aniline in aqueous solution is ionized by 308 nm photon to give hydrated electron and neutral radical resulting from rapid deprotonation of radical cation of aniline. The pKa value is found to be 7.5, and the quantum yield of the photo ionization is 0.08. Time –resolved pulse radiolysis has been used to study the reaction of aniline with ·OH, and it was established that 36% ·OH radical react directly with the –NH 2 moiety resulting in anilino radical. The main primary process (54%) is the ortho-directed ·OH-adduct.The remaining 10% ·OH attack most probably the para position of the aniline ying.