大气中有机酸强化均相核化机制的理论研究

发布时间：2018-01-06 08:21

本文关键词：大气中有机酸强化均相核化机制的理论研究　出处：《山东大学》2015年硕士论文　论文类型：学位论文

【摘要】：大气中新粒子生成机制和增长特性的研究对于理解区域空气污染和全球气候变化具有十分重要的意义,但到目前为止,没有一种完善的核化理论能够完美解释大气新粒子生成机制。尽管大气气溶胶中已被证明含有有机成分,但有机酸参与成核的化学本质和物理化学过程仍不清楚。本论文对常见有机酸成核效率进行对比确认了催化成核能力强的物种,并研究了其在大气中强化均相核化的机制,为加深对有机物参与成核机制的理解提供参考。本论文采用量子化学密度泛函理论,在PW91PW91/6-311++G(3df,3pd)水平上计算,得到以下有意义的研究结果：(1)对甲酸、乙酸等大气中14种常见的有机酸参与成核的效率进行了对比,发现这14种有机酸与硫酸形成二聚体的稳定性大多接近或超过了硫酸-硫酸二聚体,其中丁二酸、苯甲酸、苯乙酸、乙酸与硫酸形成的二聚体最稳定。甲酸等14种有机酸与氨气、有机胺形成的二聚体不如硫酸-氨气／有机胺稳定,但有机酸、有机胺等在大气中浓度较高,能形成稳定分子团簇并参与较大的复杂多组分分子团簇形成。通过对甲酸等十四种常见的有机酸、硫酸与氨气／甲胺/二甲胺形成稳定分子团簇的效率进行比较,确定了丙二酸、丁二酸和富马酸是对这些有机酸-硫酸-氨气／有机胺分子团簇稳定效果最明显的有机酸。(2)丙二酸、富马酸与有机胺成核效率低于硫酸-有机胺。水化作用会降低丙二酸、富马酸对有机胺反应活性,但能提高有机胺对这两种有机酸的反应活性。丙二酸-二甲胺成核效率高于丙二酸-甲胺成核效率。丙二酸和富马酸对二甲胺的稳定效果相近,丙二酸在大气中浓度通常高于富马酸,因此丙二酸对稳定有机胺形成稳定团簇的贡献大于富马酸。(3)丙二酸、富马酸对大气中多组分成核具有显著的强化效果,且两种有机酸对二甲胺参与的多组分成核催化效率更高。从热力学角度,丙二酸和富马酸在大气中更倾向于与有机胺形成稳定水化分子团簇,协同催化硫酸成核。
[Abstract]:Study on the formation mechanism and growth characteristics of new particles in the atmosphere is of great significance for understanding the regional air pollution and global climate change, but so far, not a perfect nucleation theory can perfectly explain the atmospheric new particle formation mechanism. Although the atmospheric aerosol has been shown to contain organic ingredients, but the organic acid in the chemical and physical and chemical nature of nuclear process remains unclear. In this paper, the common organic acid nucleating efficiency comparison confirmed the catalytic nucleation ability of the species, and to study the enhancement of homogeneous nucleation mechanism in the atmosphere, in order to enhance and provide reference for organic compounds are involved in nucleation mechanism understanding. This thesis is based on the quantum chemical density functional theory, the PW91PW91/6-311++G (3DF, 3pd) on the level of calculation, get the following significant research results: (1) of formic acid, acetic acid in the atmosphere of 14 kinds of common organic Acids are involved in nucleation efficiency were compared, found that 14 kinds of organic acid and sulfuric acid to form two dimer stability are close to or more than two sulfuric acid dimer, including succinic acid, benzoic acid, phenylacetic acid, acetic acid and sulfuric acid to form two dimer is the most stable. 14 kinds of organic acid and formic acid ammonia, organic amine formed two dimers as sulfuric acid and ammonia / organic amine is stable, but the organic acid, organic amine concentration in the atmosphere is higher, can form stable clusters and participate in more complex multicomponent molecular clusters. The acid fourteen kinds of organic acid, comparison the efficiency of sulfuric acid and ammonia / methylamine / two methylamine to form stable molecular clusters, the malonic acid, succinic acid and fumaric acid is the stabilizing effect of these organic acid - sulfuric acid ammonia / organic amine molecular clusters. The most obvious organic acid (2) malonic acid, fumaric acid and organic amine into Nuclear efficiency is lower than the sulfuric acid and organic amine. The hydration will reduce malonic acid, fumaric acid in organic amine reaction activity, but can increase the reaction activity of organic amine on the two kinds of organic acid. Malonic acid - two methylamine nucleation efficiency is higher than that of malonic acid - methylamine nucleation efficiency. Stable effect of malonic acid and fumaric acid on a two amine similar, malonic acid concentration in the atmosphere is usually higher than the fumaric acid, malonic acid to form stable clusters of stable organic amine contributed more than fumaric acid. (3) malonic acid, fumaric acid in the atmosphere of the multispecies nucleus had significant enhancement effect, and two kinds of organic acids in higher catalytic efficiency into nuclear group two different participation. From the view of thermodynamics, malonic acid and fumaric acid in the atmosphere tends to form a stable water molecular cluster and organic amine sulfate, synergistic catalytic nucleation.

【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X513

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