Oxidation of Dipropyl Thiosulfinate Initiated by Cl Radicals in the Gas Phase: Implications for Atmospheric Chemistry
Oxidation of Dipropyl Thiosulfinate Initiated by Cl Radicals in the Gas Phase: Implications for Atmospheric Chemistry
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DOI：
10.1021/acsearthspacechem.1c00246
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发表时间：
2021-09
影响因子：
3.4
通讯作者：
Parandaman Arathala;R. Musah
中科院分区：
文献类型：
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作者：
Parandaman Arathala;R. Musah
采用从头算/密度泛函理论电子结构计算方法研究了氯自由基（·Cl）引发的硫代亚磺酸二丙酯（DPTS）气相常压氧化反应机理. DPTS +·Cl反应通过夺氢和取代途径进行。结果表明，Cl自由基与DPTS的亚磺酰基[S（NOO）]上的S原子发生加成反应，随后S（NOO）-S单键断裂，生成丙烷亚磺酰氯和丙烷乙酰基（PTR）.相对于分离的起始反应物，该反应的势垒高度估计为−12.2 kcal mol-1。在200-300 K的大气相关温度范围和1 atm压力下，使用多能阱反应（MESMER）动力学代码的主方程求解器计算所有可能的H-提取和取代路径的速率系数。所有反应路径的速率系数数据表明，DPTS +·Cl反应生成丙烷亚磺酰氯和PTR是主要的反应路径，在298 K和1 atm压力下，该反应的速率系数为1.60 × 10- 10 cm-3 molecule-1 s-1。在298 K时，DPTS +·Cl反应的总速率系数为1.814 × 10- 10 cm-3 molecule-1 s-1。在200 ~ 300 K和1atm的温度范围内，DPTS的大气寿命为103 h。此外，每个反应的分支比分数进行了测定和大气的影响进行了讨论。总体而言，结果表明，虽然DPTS + Cl自由基反应的主要产物是短暂的，但其随后的氧化降解形成的化合物确实有助于全球变暖，并有可能表现出不利的环境影响。
The reaction mechanism for chlorine radical (•Cl)-initiated atmospheric oxidation of dipropyl thiosulfinate (DPTS) in the gas phase was investigated using ab initio/density functional theory electronic structure calculations. The DPTS +•Cl reaction proceeds by H-abstraction and substitution pathways. The results indicate that the Cl radical adds to the S-atom of the sulfinyl [S(═O)] group of DPTS, which is followed by cleavage of the S(═O)–S single bond, leading to the formation of propanesulfinyl chloride and propanethiyl radical (PTR). The barrier height for this reaction was estimated to be −12.2 kcal mol–1relative to the separated starting reactants. The rate coefficients were calculated for all possible H-abstraction and substitution paths using the master equation solver for the multi-energy well reactions (MESMER) kinetic code in the atmospherically relevant temperature range of 200–300 K and at 1 atm pressure. The rate coefficient data for all reaction paths indicate that the formation of propanesulfinyl chloride and PTR from the DPTS +•Cl reaction is the major path. The rate coefficient for this reaction was estimated to be ∼6.00 × 10–10cm3molecule–1s–1at 298 K and 1 atm pressure. The overall rate coefficient for the DPTS +•Cl reaction in the same temperature range was found to be ∼8.14 × 10–10cm3molecule–1s–1at 298 K. The atmospheric lifetime of DPTS was calculated to be ∼3 h in the temperatures between 200 and 300 K and at 1 atm. In addition, the branching ratio fractions for each reaction were determined and the atmospheric implications are discussed. Overall, the results reveal that while the primary products of the DPTS + Cl radical reaction are short-lived, the compounds formed from their subsequent oxidative degradation do contribute to global warming and have the potential to exhibit adverse environmental impacts.