New mechanistic pathways for the formation of organosulfates catalyzed by ammonia and carbinolamine formation catalyzed by sulfuric acid in the atmosphere
New mechanistic pathways for the formation of organosulfates catalyzed by ammonia and carbinolamine formation catalyzed by sulfuric acid in the atmosphere
复制标题
大气中氨催化有机硫酸盐形成和硫酸催化甲醇胺形成的新机制途径
DOI：
10.1039/c9cp06297a
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发表时间：
2020
影响因子：
3.3
通讯作者：
Long Bo
中科院分区：
文献类型：
--
作者：
Tan Xing-Feng;Zhang Lin;Long Bo
在二次有机气溶胶的形成过程中，探索成核前体的形成过程对于理解二次有机气溶胶的形成具有重要意义。本文利用接近CCSD(T)/CBS精度的高水平W2X//QCISD/cc-pV(T+d)Z方法，结合多结构变分过渡态理论的双能级动力学策略，在M08-SO/ maugg -cc- pvtz水平上包含小曲率隧道效应，在W2X//QCISD/cc-pV(T+d)Z水平上采用传统过渡态理论，以及扭转非调和性，报道了大气气相中有机硫酸盐和碳胺形成的新机制途径。然而，先前提出的一种机制表明，这些仅在非均相大气化学过程中形成。此外，我们发现在某些大气条件下，氨只对HCHO + H2SO4反应产生有机硫酸盐起催化作用，而硫酸能显著促进HCHO + NH3反应，从而在大气中生成碳胺。这些计算结果还表明，氨催化甲醛与硫酸的反应对甲醛的损失有重要作用，硫酸催化甲醛与氨的反应在某些大气条件下也会导致氨的损失。理论上，已经设计了详细的计算策略来获得这里研究的反应的定量速率常数。由于重交效应，HCHO和H2SO4⋯NH3之间的反应速率常数也显著降低。此外，计算结果表明，M08-SO官能团可以提供可靠的结果来描述所研究的反应，无符号误差条小于1 kcal mol−1。
In the secondary organic aerosol formation, exploring the formation of nucleation precursors is of paramount importance for understanding the secondary organic aerosol formation. Here, we report new mechanistic pathways for the formation of organosulfates and carbinolamine in the atmospheric gas phase by utilizing a high-level W2X//QCISD/cc-pV(T+d)Z method close to CCSD(T)/CBS accuracy, dual level kinetics strategy by combining multistructural variational the transition state theory, containing small-curvature tunneling at the M08-SO/maug-cc-pVTZ level with the conventional transition state theory at the W2X//QCISD/cc-pV(T+d)Z level, and torsional anharmonicity. However, a previously suggested mechanism indicated that these are only formed in the heterogeneous atmospheric chemical processes. Furthermore, we find that ammonia only exerts a catalytic role in the HCHO + H2SO4 reaction responsible for the formation of organosulfates under some atmospheric conditions, whereas sulfuric acid can significantly promote the HCHO + NH3 reactions, resulting in the formation of carbinolamine in the atmosphere. These calculated results also show that the ammonia-catalyzed reaction of formaldehyde with sulfuric acid can play an important role in the loss of formaldehyde and the sulfuric acid-catalyzed reaction of formaldehyde with ammonia can also contribute towards the loss of ammonia under some atmospheric conditions. In theory, detailed computational strategies have been designed to obtain quantitative rate constants for the reactions investigated here. A remarkable decrease in the rate constant of the reaction between HCHO and H2SO4⋯NH3 is also observed due to recrossing effects. In addition, the calculated results show that M08-SO functional can provide reliable results for describing the reactions studied here with unsigned error bars of less than 1 kcal mol−1.