大气中一元酸催化亚硫酸分解反应的从头算及动力学研究

发布时间：2018-02-10 13:13

本文关键词： 亚硫酸一元酸催化从头算速率常数　出处：《高等学校化学学报》2017年08期 　论文类型：期刊论文

【摘要】：采用从头算的理论计算方法,在CCSD(T)/aug-cc-p VDZ//MP2/aug-cc-p VDZ水平下,对甲酸、乙酸、丙酸和硝酸催化亚硫酸分解成二氧化硫和水的微观反应机理进行了理论研究.结果表明,这4种一元酸均可使亚硫酸分解反应能垒显著降低,降低幅度由大到小的顺序为丙酸乙酸甲酸硝酸.其中,丙酸甚至使反应能垒从裸反应时的99.84 kJ/mol降至27.24 kJ/mol.在此基础上,计算了200~320 K温度范围内4种一元酸催化亚硫酸分解反应的速率常数,并结合它们在大气中的实际浓度计算了有效速率常数.结果表明,在实际大气环境中,乙酸对亚硫酸分解反应的催化效果最为显著.当乙酸存在时,亚硫酸在室温下的大气寿命仅为0.02 s.
[Abstract]:The microcosmic reaction mechanism of sulfuric acid, acetic acid, propionic acid and nitric acid catalyzed by sulfurous acid to sulfur dioxide and water was studied by ab initio theoretical calculation method at the level of CCSD(T)/aug-cc-p VDZ//MP2/aug-cc-p VDZ. These four monoacids can significantly decrease the energy barrier of sulfurous acid decomposition reaction, and the order of reduction from large to small is nitric acid propionate acetate. Propionic acid even reduces the energy barrier from 99.84 kJ/mol to 27.24 kJ / mol during naked reaction. The rate constants for the decomposition of sulfurous acid catalyzed by four monobarboxylic acids in the temperature range of 200 ~ 320 K have been calculated, and the effective rate constants have been calculated in combination with their actual concentrations in the atmosphere. The results show that, in the actual atmospheric environment, the effective rate constants are calculated. In the presence of acetic acid, the atmospheric lifetime of sulfurous acid at room temperature is only 0.02 s.
【作者单位】：吉林大学理论化学研究所理论化学计算实验室;加州州立大学富勒尔顿分校化学与生物化学系;
【基金】：国家自然科学基金(批准号:21373098)资助~~
【分类号】：O643.32

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