<br>揭示氨基甲醇 (NH2CH2OH) 的化学动力学：深入了解 OH 和 O2 光氧化反应以及甲酰胺的优势,Frontiers in Chemistry

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揭示氨基甲醇 (NH2CH2OH) 的化学动力学：深入了解 OH 和 O2 光氧化反应以及甲酰胺的优势
Frontiers in Chemistry ( IF 3.8 ) Pub Date : 2024-05-30 , DOI: 10.3389/fchem.2024.1407355
Naga Venkateswara Rao Nulakani ₁ , Mohamad Akbar Ali _{1,

2}

Affiliation

氨基甲醇通过各种来源释放到大气中，包括生物质燃烧。在这项研究中，我们阐述了氨基甲醇在羟基自由基引发的反应途径中的化学动力学（氧˙ H) 借助从头开始//密度泛函理论（DFT） IE , 耦合簇理论 (CCSD(T))//混合 DFT (M06-2X/6-311++G (3df, 3pd)。我们已经探索了各种可能的方向氧˙氨基甲醇上的 H 自由基，以及独特的预反应复合物的形成。我们的计算结果表明，H 转移需要来自 –CH 的活化能范围为 4.1 至 6.5 kcal/mol 2基团，3.5–6.5 kcal/mol，来自 –NH 2基团和 7-9.3 kcal/mol 来自三个旋转构象异构体的 -OH 基团。 H从-CH转移2 ,-NH 2 -OH 表现出估计的总速率常数（ k哦）约为 1.97 × 10 −11厘米3分子−1 s −1 300 K 时。支化分数分析表明以 C 为中心的 NH 占显着优势2 C ˙ HOH自由基好感度高达77%，超越N中心自由基氮˙六六六六2 OH (20%) 和 O 中心 NH 2 CH 2氧˙ (3%) 自由基。此外，我们的研究深入研究了备受青睐的碳中心 NH 的氧化2 C ˙ HOH 自由基通过与大气氧分子的相互作用而产生。有趣的是，我们的研究结果表明甲酰胺（NH 2 CHO) 成为 NH 的主要产品2 C ˙羟基+ 3氧2反应，使其他结果黯然失色，例如氨基甲酸（NH 2 COOH) 和甲亚胺酸 (HN = C(H)-OH)。在与对流层相关的大气条件下，甲酰胺形成的支化分数值约为 99%，速率常数为 5.5 × 10 −12厘米3分子−1 s −1 。最后，我们仔细研究了甲酰胺对大气的有害影响。甲酰胺与大气中的羟基自由基相互作用可能会产生潜在危险的化合物，例如 HNCO。另外，未反应的氮˙六六六六2 OH自由基与痕量N-氧化物（即NO和NO）反应时可能引发致癌亚硝胺的形成2 ）。这反过来又加剧了环境风险因素。

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Unveiling the chemical kinetics of aminomethanol (NH2CH2OH): insights into O.H and O2 photo-oxidation reactions and formamide dominance

Aminomethanol is released into the atmosphere through various sources, including biomass burning. In this study, we have expounded the chemical kinetics of aminomethanol in the reaction pathways initiated by the hydroxyl radical (O˙H) with the aid of ab initio//density functional theory (DFT) i.e., coupled-cluster theory (CCSD(T))//hybrid-DFT (M06-2X/6-311++G (3df, 3pd). We have explored various possible directions of the O˙H radical on aminomethanol, as well as the formation of distinct pre-reactive complexes. Our computational findings reveal that the H transfer necessitates activation energies ranging from 4.1 to 6.5 kcal/mol from the –CH2 group, 3.5–6.5 kcal/mol from the –NH2 group and 7–9.3 kcal/mol from the –OH group of three rotational conformers. The H transfer from –CH2, –NH2 and –OH exhibits an estimated total rate constant (kOH) of approximately 1.97 × 10−11 cm3 molecule−1 s−1 at 300 K. The branching fraction analysis indicates a pronounced dominance of C-centered NH2C˙HOH radicals with a favorability of 77%, surpassing the N-centered N˙ HCH2OH (20%) and O-centered NH2CH2O˙ (3%) radicals. Moreover, our investigation delves into the oxidation of the prominently favored carbon-centered NH2C˙HOH radical through its interaction with atmospheric oxygen molecules. Intriguingly, our findings reveal that formamide (NH2CHO) emerges as the predominant product in the NH2C˙HOH + 3O2 reaction, eclipsing alternative outcomes such as amino formic acid (NH2COOH) and formimidic acid (HN = C(H)-OH). At atmospheric conditions pertinent to the troposphere, the branching fraction value for the formation of formamide is about 99%, coupled with a rate constant of 5.5 × 10−12 cm3 molecule−1 s−1. Finally, we have scrutinized the detrimental impact of formamide on the atmosphere. Interaction of formamide with atmospheric hydroxyl radicals could give rise to the production of potentially perilous compounds such as HNCO. Further, unreacted N˙HCH2OH radicals may initiate the formation of carcinogenic nitrosamines when reacting with trace N-oxides (namely, NO and NO2). This, in turn, escalates the environmental risk factors.

更新日期：2024-05-30

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