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  

Ab initio Calculation and Kinetic Investigation of Monacid-catalyzed Decomposition of Sulfurous Acid

作　　者：方升[1] 刘静静[1] 段雪梅[1] 陶福明[2] 刘靖尧[1] 

机构地区：[1]吉林大学理论化学研究所理论化学计算实验室,长春130023 [2]加州州立大学富勒尔顿分校化学与生物化学系,美国加利福尼亚92834

出　　处：《高等学校化学学报》2017年第8期1390-1398,共9页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金(批准号:21373098)资助~~

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.The mechanism of decomposition of sulfurous acid to sulfur dioxide and water catalyzed by formic acid, acetic acid, propionic acid and nitric acid, respectively, was investigated by ab initio calculations at the CCSD（T）/aug-cc-pVDZ//MP2/aug-cc-pVDZ level of theory herein. The computational results showed that all the four acids presented catalytic effect for the decomposition of sulfurous acid. The reduction extent of the energy barrier was in the order propionic acid〉acetic acid〉formic acid〉nitric acid. Furthermore, the energy barrier of propionic acid-catalyzed reaction decreased dramatically from 99. 84 kJ/mol of naked reaction to 27.24 kJ/mol. The rate constants of the catalyzed reactions in the temperature range of 200--320 K had been calculated. In addition, the effective rate constants were also calculated in combination with the atmospheric concentrations of these acids. The results indicated that the acetic acid had the most effective catalytic effect in the atmospheric environment, and the lifetime of sulfurous acid was only 0.02 s with the appearance of acetic acid.

关 键 词：亚硫酸 一元酸 催化 从头算 速率常数 

分 类 号：O641[理学—物理化学]