【作者】 刘艳丽； 陈龙； 周丽婷； 王渭娜； 王文亮；

【Author】 Yanli Liu;Long Chen;Liting Zhou;Weina Wang;Wenliang Wang;School of Chemistry and Chemical Engineering, Key Laboratory for Macromolecular Science of Shaanxi Province, Shaanxi Normal University;

【机构】 陕西省大分子科学重点实验室陕西师范大学化学化工学院；

【摘要】 过氧自由基是对流层大气化学反应和初步形成气溶胶粒子的重要物种,研究其反应活性对改善大气环境具有重要意义。因此本文采用CCSD（T）/6-311++G（d,p）//B3LYP/6-311+G（d,p）方法研究了C₂H₅O₂和OH自由基的反应机理。结果表明,标题反应主要存在抽氢、加成-消除和取代反应3种类型反应机理,且既可以发生在单重态势能面上,也可以发生在三重态势能面上。单重态势能面以加成-消除反应生成P3（CH3CHO+H₂O2）为优势反应路径,表观活化能为30.31 kJ?mol^-1。三重态势能面以抽氢反应生成PC7（³CH₃CHO₂???H₂O）为优势反应路径,表观活化能为16.46 kJ?mol^-1。速率常数计算结果显示,单、三重态优势路径在温度298 K时的速率常数分别为2.91×10^-18和1.03×10^-15 cm³?molecule^-1?s^-1,且在200-1000 K温度范围内均表现为正温度系数效应。更多还原

【Abstract】 The chemistry of organic peroxy radicals plays a central role in the chemistry of the Earth’s troposphere and the formation of initial organic aerosol particle. The detailed reaction mechanisms are investigated for reaction C₂H₅O₂ with OH at the CCSD（T）/6-311++G（d,p）//B3LYP/6-311+G（d,p） level. The results show that the title reaction occurs both on the singlet and triplet potential energy surface, including H-Abstraction, addition-elimination and substitution mechanism. The addition-elimination reaction to produce P3（CH₃CHO+H₂O₂）is the dominate pathway on the singlet with the apparent activation energy 30.31 kJ?mol^-1. While the main pathway on the triplet is H-abstraction reaction, leading to the formation of PC7（³CH₂CH₂O₂???H₂O） with apparent activation energy 16.46 kJ ?mol^-1. The calculated results show that rate constants of main channels on the singlet and triplet are 2.91×10^-18 and 1.03×10^-15 cm³?molecule^-1?s^-1, respectively. Within the temperature range of 200-1000 K, rate constants of two pathways are increased as the temperature rising.更多还原