脉冲辐解研究喹啉和异喹啉与瞬态粒子的反应

通过合理控制反应条件, 使体系在电子束脉冲作用后只剩下所需要的一种瞬态粒子, 用脉冲辐解研究了喹啉、异喹啉分别与水合电子、羟基自由基、氢自由基等几种典型的氧化还原瞬态粒子的反应过程, 研究了各种瞬态产物的吸收光谱及其变化规律, 测定了相关反应的速率常数. 喹啉、异喹啉与水合电子的反应速率常数分别为7.1×10⁹和3.4×10⁹ mol^-1·L·s^-1, 与羟基自由基的反应速率常数分别为7.2×10⁹和3.4×10⁹ mol^-1·L·s^-1, 与氢自由基的反应速率常数分别为5.7×10⁹和3.6×10⁹ mol^-1·L·s^-1. 这一结果表明, 喹啉、异喹啉均能够非常迅速地与水合电子、羟基自由基、氢自由基发生反应, 喹啉比异喹啉的反应速率更快. 运用电子理论分析了瞬态反应产物结构的稳定性差异, 结果表明, 喹啉的反应产物比异喹啉的稳定, 从而揭示了喹啉比异喹啉反应速率快的原因.

Studies on the Respective Reactions of Quinoline and Isoquinoline with Transient Species by Pulse Radiolysis

Respective reactions of quinoline and isoquinoline with typical oxidative/reductive transient species, i.e., hydrated electrons, hydroxyl radicals, and hydrogen atoms (obtained after the reaction of an electron beam by proper condition-controlling) were investigated by pulse radiolysis. Absorption spectra of the transient products and their change trends were investigated. Reaction rate constants of hydrated electrons with quinoline and isoquinoline were 7.1×10⁹ and 3.4×10⁹ mol^-1·L·s^-1, respectively. The hydroxyl radical had rate constants of 7.2×10⁹ and 3.4×10⁹ mol^-1·L·s^-1, respectively. The rate constants of hydrogen atoms were 5.7×10⁹ and 3.6×10⁹ mol^-1·L·s^-1, respectively. Results showed that both quinoline and isoquinoline reacted with hydrated electrons, hydroxyl radicals, and hydrogen atoms very quickly. However, reaction rates of quinoline with these transient reductive/oxidative species were faster than that of isoquinoline. Stabilities of the transient products from these reactions were analyzed by electron theory. Reaction products from quinoline’s reaction with transient species were found to be more stable than reaction products from the isoquinoline reaction and this difference was the reason for the difference in rate constants.