1. Atmospheric Chemistry of CH 2 OO: The Hydrolysis of CH 2 OO in Small Clusters of Sulfuric Acid.
- Author
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Wang R, Wen M, Chen X, Mu R, Zeng Z, Chai G, Lily M, Wang Z, and Zhang T
- Abstract
The hydrolysis of CH
2 OO is not only a dominant sink for the CH2 OO intermediate in the atmosphere but also a key process in the formation of aerosols. Herein, the reaction mechanism and kinetics for the hydrolysis of CH2 OO catalyzed by the precursors of atmospheric aerosols, including H2 SO4 , H2 SO4 ···H2 O, and (H2 SO4 )2 , have been studied theoretically at the CCSD(T)-F12a/cc-pVDZ-F12//B3LYP/6-311+G(2 df ,2 pd ) level. The calculated results show that the three catalysts decrease the energy barrier by over 10.3 kcal·mol-1 ; at the same time, the product formation of HOCH2 OOH is more strongly bonded to the three catalysts than to the reactants CH2 OO and H2 O, revealing that small clusters of sulfuric acid promote the hydrolysis of CH2 OO both kinetically and thermodynamically. Kinetic simulations show that the H2 SO4 -assisted reaction is more favorable than the H2 SO4 ···H2 O- (the pseudo-first-order rate constant being 27.9-11.5 times larger) and (H2 SO4 )2 - (between 2.8 × 104 and 3.4 × 105 times larger) catalyzed reactions. Additionally, due to relatively lower concentration of H2 SO4 , the hydrolysis of CH2 OO with H2 SO4 cannot compete with the CH2 OO + H2 O or (H2 O)2 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.- Published
- 2021
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