理论研究甲胺和二甲胺存在下的二氧化氮的气态水解反应

发布时间：2018-06-16 04:21

本文选题：有机胺 + 反应机理　；参考：《东北师范大学》2017年硕士论文

【摘要】：在大气污染化学中,亚硝酸(HONO)与含氮颗粒物同为典型的二次污染物,两者密不可分。亚硝酸被认为是重要的对流层的痕量气体,它可以经过光照分解而释放大量的OH自由基。尽管亚硝酸的重要性已经被意识到,但是对于它的来源及其形成的化学机理,还没有得到很好地认识和理解。本文研究了甲胺和二甲胺对二氧化氮水解反应的影响,并与氨气进行对比。通过量子化学理论计算了一系列分子簇,包括2NO_2-mH_2O-CH_3NH_2(m=1-3)和2NO_2-mH_2O-(CH_3)_2NH(m=1,2)。具体反应过程如下:2NO_2(g)+ mH_2O(g)+ CH_3NH_2(g)→Products(m=1-3)2NO_2(g)+ mH_2O(g)+(CH_3)_2NH(g)→Products(m=1,2)结果表明,在二氧化氮水解反应过程中,甲胺和二甲胺比氨气具有更大的热力学影响。反应中增加的水分子不仅可以稳定过渡态和产物复合物,并且能促进硝酸盐的形成。当分子簇中存在甲胺时,反应过程中的能垒降低了3.2 kcal mol-1,产物复合物更加稳定。在硝酸的水合作用中,甲胺和二甲胺也比氨气具有更大的影响,随着水分子的增加,物质NH4NO3,CH_3NH_3NO3和(CH_3)_2NH_2NO3都倾向于形成更大的气溶胶分子。同时,本文也研究了复合物HONO-CH_3NH_2和HONO-NH_3的平衡结构,谐波振动频率和强度。计算结果表明,复合物HONO-CH_3NH_2的结合能均强于HONO-NH_3复合物,OH伸缩振动频率和强度是受复合物形成的影响最大的。给受体间作用的NBO分析结果表明,在甲胺和二甲胺存在下的分子簇间的相互作用要大于氨气存在的情况,复合物HONO-CH_3NH_2中存在更大的二阶稳定化能。
[Abstract]:In atmospheric pollution chemistry, HONO2 and N-containing particulates are typical secondary pollutants, which are closely related to each other. Nitrite is considered to be an important tropospheric trace gas, which can release a large amount of OH free radicals by light decomposition. Although the importance of nitrite has been recognized, its source and the chemical mechanism of its formation have not been well understood and understood. The effects of methylamine and dimethylamine on the hydrolysis of nitrogen dioxide were studied and compared with ammonia. A series of molecular clusters have been calculated by quantum chemistry theory, including 2NOS _ 2mH _ 2O-CH3NH _ 2T _ 2M _ 3) and 2NO _ 2-mH _ 2O-T _ 2H _ 2O-T _ 2NH _ m _ 3. The specific process of the reaction is as follows: 2NO2G) mH2Og) Ch 3NH / 2G) Productsm (1 / 3N / 2NO2G) / mH2Og) the results show that methylamine and dimethylamine have a greater thermodynamic effect than ammonia in the process of the hydrolysis of nitrogen dioxide by means of the following steps: CH3NO2G) / mH2OG) / Ch _ 3NO2G) / D _ 2N _ 2H _ 2H _ 2O _ 2g)] the results show that during the hydrolysis of nitrogen dioxide, methylamine and dimethylamine have a greater thermodynamic effect than ammonia in the process of hydrolysis of nitrogen dioxide. The addition of water molecules can not only stabilize the transition state and product complex, but also promote the formation of nitrate. When methylamine is present in the molecular cluster, the energy barrier decreases by 3.2 kcal mol-1 during the reaction, and the product complex is more stable. In the water cooperation of nitric acid, methylamine and dimethylamine also have more influence than ammonia. With the increase of water molecule, the substance NH _ 4NO _ 3 / C _ 3NH _ 3NO _ 3 and Ch _ 3s _ 2NH _ 3NO _ 3 are all inclined to form larger aerosol molecules. At the same time, the equilibrium structure, harmonic vibration frequency and intensity of the composite HONO-CH3NH _ 2 and HONO-NH3 are also studied. The results show that the binding energy of HONO-CH3NH2 is stronger than that of HONO-NH3 complex. The frequency and intensity of OH stretching vibration of HONO-CH3NH2 complex are the most affected by the formation of the complex. The results of NBO analysis for the interaction between the receptors show that the interaction between the clusters in the presence of methylamine and dimethylamine is greater than that in the presence of ammonia, and there is a greater second order stabilization energy in the complex HONO-CH3NHStack2.
【学位授予单位】：东北师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O643.12

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