Kinetics and Mechanism of the Singlet Oxygen Atom Reaction with Dimethyl Ether.

We combine in situ laser spectroscopy, quantum chemistry, and kinetic calculations to study the reaction of a singlet oxygen atom with dimethyl ether. Infrared laser absorption spectroscopy and Faraday rotation spectroscopy are used for the detection and quantification of the reaction products OH, H2O, HO2, and CH2O on submillisecond time scales. Fitting temporal profiles of products with simulations using an in-house reaction mechanism allows product branching to be quantified at 30, 60, and 150 Torr. The experimentally determined product branching agrees well with master equation calculations based on electronic structure data and transition state theory. The calculations demonstrate that the dimethyl peroxide (CH3OOCH3) generated via O-insertion into the C-O bond undergoes subsequent dissociation to CH3O + CH3O through energetically favored reactions without an intrinsic barrier. This O-insertion mechanism can be important for understanding the fate of biofuels leaking into the atmosphere and for plasma-based biofuel processing technologies.

我们结合原位激光光谱学、量子化学和动力学计算来研究单重态氧原子与二甲醚的反应。红外激光吸收光谱和法拉第旋转光谱用于在亚毫秒时间尺度上对反应产物OH、H₂O、HO₂和CH₂O进行检测和定量。利用内部反应机制通过模拟对产物的时间分布进行拟合，可以在30、60和150托的条件下对产物分支比进行定量。实验确定的产物分支比与基于电子结构数据和过渡态理论的主方程计算结果吻合良好。计算表明，通过氧原子插入C - O键生成的过氧化二甲酯（CH₃OOCH₃）会通过能量有利且无内在势垒的反应随后解离为CH₃O + CH₃O。这种氧插入机制对于理解生物燃料泄漏到大气中的归宿以及基于等离子体的生物燃料处理技术具有重要意义。