Wang Rui, Wen Mingjie, Chen Xu, Mu Ruxue, Zeng Zhaopeng, Chai Guang, Lily Makroni, Wang Zhiyin, Zhang Tianlei
Institute of Theoretical and Computational Chemistry, Shaanxi Key Laboratory of Catalysis, School of Chemical & Environment Science, Shaanxi University of Technology, Hanzhong, Shaanxi 723001, P. R. China.
Key Laboratory for Macromolecular Science of Shaanxi Province, School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi'an, Shaanxi 710062, P. R. China.
J Phys Chem A. 2021 Apr 1;125(12):2642-2652. doi: 10.1021/acs.jpca.1c02006. Epub 2021 Mar 23.
The hydrolysis of CHOO is not only a dominant sink for the CHOO intermediate in the atmosphere but also a key process in the formation of aerosols. Herein, the reaction mechanism and kinetics for the hydrolysis of CHOO catalyzed by the precursors of atmospheric aerosols, including HSO, HSO···HO, and (HSO), have been studied theoretically at the CCSD(T)-F12a/cc-pVDZ-F12//B3LYP/6-311+G(2,2) level. The calculated results show that the three catalysts decrease the energy barrier by over 10.3 kcal·mol; at the same time, the product formation of HOCHOOH is more strongly bonded to the three catalysts than to the reactants CHOO and HO, revealing that small clusters of sulfuric acid promote the hydrolysis of CHOO both kinetically and thermodynamically. Kinetic simulations show that the HSO-assisted reaction is more favorable than the HSO···HO- (the pseudo-first-order rate constant being 27.9-11.5 times larger) and (HSO)- (between 2.8 × 10 and 3.4 × 10 times larger) catalyzed reactions. Additionally, due to relatively lower concentration of HSO, the hydrolysis of CHOO with HSO cannot compete with the CHOO + HO or (HO) reaction within the temperature range of 280-320 K, since its pseudo-first-order rate ratio is smaller by 4-7 or 6-8 orders of magnitude, respectively. However, the present results provide a good example of how small clusters of sulfuric acid catalyze the hydrolysis of an important atmospheric species.
CHOO的水解不仅是大气中CHOO中间体的主要汇，也是气溶胶形成的关键过程。在此，在CCSD(T)-F12a/cc-pVDZ-F12//B3LYP/6-311+G(2,2)水平上对包括HSO、HSO···HO和(HSO)在内的大气气溶胶前体催化CHOO水解的反应机理和动力学进行了理论研究。计算结果表明，这三种催化剂使能垒降低了超过10.3 kcal·mol；同时，HOCHOOH的产物形成与这三种催化剂的结合比与反应物CHOO和HO的结合更强，这表明硫酸小簇在动力学和热力学上都促进了CHOO的水解。动力学模拟表明，HSO辅助反应比HSO···HO-（伪一级速率常数大27.9-11.5倍）和(HSO)-（大2.8×10至3.4×10倍）催化的反应更有利。此外，由于HSO浓度相对较低，在280-320 K的温度范围内，CHOO与HSO的水解不能与CHOO + HO或(HO)反应竞争，因为其伪一级速率比分别小4-7或6-8个数量级。然而，目前的结果为硫酸小簇如何催化一种重要大气物质的水解提供了一个很好的例子。
