Nitrosamine Formation in Amine-Based CO2 Capture in the Absence of NO2: Molecular Modeling and Experimental Validation
Nitrosamine Formation in Amine-Based CO2 Capture in the Absence of NO2: Molecular Modeling and Experimental Validation
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无 NO2 时胺基 CO2 捕集中亚硝胺的形成：分子模型和实验验证
DOI：
10.1021/acs.est.6b05601
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Max Ball
中科院分区：
文献类型：
--
作者：
Huancong Shi;Teeradet Supap;Raphael Idem;Don Gelowitz;Colin Campbell;Max Ball
使用计算化学方法来阐明和验证不同的亚硝胺形成机制和途径。这些包括在存在 NO、O2、SO2 和 CO2 且不含 NO2 的酸性或碱性环境下形成亚硝胺。结果清楚地表明，亚硝胺可以通过两种不同类型的机制在没有 NO2 的情况下形成，即分别在质子转移之前加成和消除形成 N−N 键和在 N−N 键形成之前质子转移。这项工作中确定的这些机制的本质是需要两个反应步骤来完成使用不同亚硝化剂的两种反应机制。如果要完成亚硝胺形成反应，两个步骤都是必要的，两个步骤都不能被忽视。对每组反应的反应物、中间体、过渡态和产物进行的计算模拟也验证了所提出的机制。实验还从二乙胺与NO、SO2、O2和CO2在液相和气相中的反应中检测到亚硝胺。因此，NO2 并不是 CO2 捕获系统中亚硝胺形成所必需的。
A computational chemistry approach was used to elucidate and verify the different nitrosamine formation mechanisms and pathways. These included nitrosamine formation under acid or basic environments in the presence of NO, O2, SO2 and CO2 without NO2. The results clearly showed that nitrosamine could be formed without NO2 via 2 different types of mechanisms, namely, addition and elimination forming N−N bond before proton transfer and proton transfer before N−N bond formation, respectively. The essence of these mechanisms identified in this work was that two reaction steps were required to complete both reaction mechanisms with different nitrosating agents. Two steps were both necessary neither of which could be neglected, if the nitrosamine formation reaction was to be completed. Computational simulation performed on the reactant, intermediate, transition state, and product for each set of reactions also validated the proposed mechanisms. Experiment also detected nitrosamine from the reaction of diethylamine and NO, SO2, O2, and CO2 in both liquid and gas phase. Thus, NO2 is not necessary for nitrosamine formation to occur in the CO2 capture system.