Criegee intermediates are thought to play roles in atmospheric chemistry, including OH radical formation, oxidation of SO₂, NO₂, etc. CH₂OO is the simplest Criegee intermediate, of which the reactivity has been a hot topic. Here we investigated the kinetics of CH₂OO reaction with dimethyl sulfoxide (DMSO) under 278–349 K and 10–150 Torr. DMSO is an important species formed in the oxidation of dimethyl sulfide in the biogenic sulfur cycle. The concentration of CH₂OO was monitored in real‐time via its mid‐infrared absorption band at about 1,286 cm⁻¹ (Q branch of the ν₄ band) with a high‐resolution quantum cascade laser spectrometer. The 298 K bimolecular rate coefficient was determined to be k₂₉₈ = (2.3 ± 0.3) × 10⁻¹² cm³/s at 30 Torr with an Arrhenius activation energy of −3.9 ± 0.2 kcal/mol and a weak pressure dependence for pressures higher than 30 Torr (k₂₉₈ = (2.8 ± 0.3) × 10⁻¹² cm³/s at 100 Torr). The reaction is speculated to undergo a five‐membered ring intermediate, analogous to that of CH₂OO with SO₂. The negative activation energy indicates that the rate‐determining transition state is submerged. The magnitude of the reaction rate coefficient lies in between those of CH₂OO reactions with (CH₃)₂CO and with SO₂.

中文翻译：

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最简单的Criegee中间体与二甲亚砜的温度依赖性动力学

Criegee中间体被认为在大气化学中起作用，包括OH自由基的形成，SO ₂，NO ₂等的氧化。CH ₂ OO是最简单的Criegee中间体，其反应性一直是热门话题。在这里，我们研究了在278–349 K和10–150 Torr下CH ₂ OO与二甲亚砜（DMSO）反应的动力学。DMSO是生物成因硫循环中二甲基硫醚氧化过程中形成的重要物种。CH的浓度₂ OO在实时经由其中红外吸收带在约1286厘米监测^-1（的Q分支ν ₄波段）和高分辨率量子级联激光光谱仪。298 K双分子速率系数经确定为在30 Torr时为k ₂₉₈ =（2.3±0.3）×10 ^-12 cm ³ / s，Arrhenius活化能为-3.9±0.2 kcal / mol，对较高压力的压力依赖性较弱。大于30托（100托时k ₂₉₈ =（2.8±0.3）×10 ^-12 cm ³ / s）。推测该反应会经历五元环中间体，类似于CH ₂ OO与SO _2的反应。负激活能表示确定速率的过渡状态已被淹没。反应速率系数的大小介于与（CH ₃）₂ CO和SO ₂进行的CH ₂ OO反应之间。