[Me3NC2H4OH]Zn2Cl5水溶液的激光光解研究

利用时间分辨激光光解技术研究了季铵盐型离子液体Me₃NC₂H₄OH]Zn₂Cl₅(简写R-Zn₂Cl₅)的光解行为, 研究发现离子液体能被266 nm激光单光子电离, 生成阳离子自由基、Zn₂Cl₅]^?中性自由基和水合电子, 观察到胆碱激发三线态的存在, 并测定了离子液体光电离的量子产额为0.04. 利用266 nm激光对离子液体、胆碱、氯化锌、氯化钠的光解行为比较, 发现胆碱阳离子的贡献很小, Zn₂Cl₅]^－阴离子起主要作用. 采用氧化性自由基SO₄^?－引发离子自由基, 揭示其光电离机理, 测定离子液体的动力学反应速率常数, SO₄^?－ 460 nm的衰减速率常数为1.3×10⁹ L?mol^－1?s^－1, 320 nm离子自由基瞬态产物的生成速率常数为1.5×10⁹ L?mol^－1?s^－1, 两者很接近, 说明SO₄^?－自由基的衰减与瞬态自由基的生成是同步的.

Studies of [Me3NC2H4OH]Zn2Cl5 Aqueous Solution by Laser Photolysis

The absorption spectra of Me₃NC₂H₄OH]Zn₂Cl₅ (R-Zn₂Cl₅) in aqueous solutions were studied by time-resolved laser photolysis, and the mechanism of monophotonic ionization was suggested. The oxidizing radical SO₄^?－ was used to produce radical cation. Comparison of R-Zn₂Cl₅ with NaCl, ZnCl₂ and choline showed that Zn₂Cl₅]^－ played an important role in photoionization while Me₃NC₂H₄OH]^?＋ cation had little function on its photolysis. Rate constant for oxidation reactions was determined in R-Zn₂Cl₅ ionic liquid. The second-order decay rate constant of SO₄^?－ oxidation reactions at 460 nm, 1.3×10⁹ L?mol^－1?s^－1, was almost equal to the product rate constant of 1.5×10⁹ L?mol^－1?s^－1 at 320 nm in R-Zn₂Cl₅ aqueous solution, showing that the decay and the product were synchronic.