Atmospheric chemistry of CH₃CHO: the hydrolysis of CH₃CHO catalyzed by H₂SO₄

Abstract

Elucidating atmospheric oxidation mechanisms and the reaction kinetics of atmospheric compounds is of great importance and necessary for atmospheric modeling and the understanding of the formation of atmospheric organic aerosols. While the hydrolysis of aldehydes has been detected in the presence of sulfuric acid, the reaction mechanism and kinetics remain unclear. Herein, we use electronic structure methods with CCSD(T)/CBS accuracy and canonical variational transition state theory combined with small-curvature tunneling to study the reaction mechanism and kinetics of the hydrolysis of CHCHO. The calculated results show that the hydrolysis of CHCHO needs to overcome an energy barrier of 37.21 kcal mol, while the energy barrier is decreased to -9.79 kcal mol with a sulfuric acid catalyst. In addition, the calculated kinetic results show that the HSOHO + CHCHO reaction is faster than HSO + CHCHOHO. Additionally, the HSOHO + CHCHO reaction can play an important role in the sink of CHCHO below 260 K occurring during the night period when OH, HSO, and HO concentrations are 10, 10, and 10 molecules cm, respectively, because it can compete well with the CHCHO + OH reaction. There are wide implications in atmospheric chemistry from these findings because of the potential importance of the catalytic effect of HSO on the hydrolysis of CHCHO in the atmosphere and in the formation of secondary organic aerosols.

Possible atmospheric source of NH2SO3H: the hydrolysis of HNSO2 in the presence of neutral, basic, and acidic catalysts

“…The values in brackets are from experiments. 10,11,21,28,29,33,34,[58][59][60][61][62][63] lengths (Å) and bond angles. [58][59][60][61][62][63] The mean absolute deviation of bond lengths (Å) and bond angles (1) between the calculations at the M06-2X/6-311+G(2df,2pd) level and the experimental values were less than 0.01 Å and 1.61, respectively.…”

“…These geometrical structures were also in good agreement with earlier findings. 21,28,29,33,34,65 The stabilization energies of (…”

Unexpected quenching effect on new particle formation from the atmospheric reaction of methanol with SO 3

“…Important common atmospheric species (SA, DMA, and H 2 O) have been detected in the atmosphere (14). These species can also act as relatively strong hydrogen-atom donors/acceptors, thereby promoting various proton transfer reactions (35,36), and possibly catalyzing the MO-SO 3 reaction. Therefore, the catalytic effects of SA/DMA/H 2 O on the MO-SO 3 reaction were also investigated.…”

Hydrolysis of Formyl Fluoride Catalyzed by Sulfuric Acid and Formic Acid in the Atmosphere

“…The mechanism for the gas-phase hydrolysis of HFCO catalyzed by H 2 SO 4 is similar to the mechanism for the reaction of HCHO + H 2 O catalyzed by H 2 SO 4 . 43,44 Similarly, the HFCO + H 2 O + H 2 SO 4 reaction proceeds by stepwise mechanistic pathways. However, a fluorine atom substitutes one hydrogen atom in HCHO, which results in the loss of C 2 v symmetry in HFCO.…”