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The reaction mechanisms for the atmospheric hydroxylation of n-butyl vinyl ether ( n-BVE), iso-butyl vinyl ether ( i-BVE), and tert-butyl vinyl ether ( t-BVE) were investigated by using quantum chemical method in this paper. The geometry optimizations and frequency calculations were carried out at the MPWB1K/6-31+G(d,p) level, and the accurate energetic parameters were obtained by the MPWB1K/6-311++g(3df,2p) method. The reaction mechanisms for the title reactions have been presented. Ten possible reaction channels were discussed for the primary hydroxylation of n-BVE and t-BVE, while fourteen pathways for i-BVE. Three favorable reaction pathways were chosen for each isomer to undergo further investigation. Major products are n-butyl formate, iso-butyl formate, tert-butyl formate, and HCHO. The rate constants of the primary reactions were calculated over the temperature range of 200-400 K and the pressure range of 100-2,000 Torr by employing MESMER program. At 298 K and 760 Torr, the whole rate constants of n-BVE + OH, i-BVE + OH, and t-BVE + OH are 12.3 × 10, 9.32 × 10 and 5.75 × 10cmmolecules, respectively. Additionally, the lifetimes of the three isomers with respect to OH radical are $$\tau$$ = 1.13 h, $$\tau$$ = 1.49 h, and $$\tau$$ = 2.41 h. [ABSTRACT FROM AUTHOR]

Highlights: [•] Reactivation process involves a trigonal bipyramidal structure. [•] The rate-determining step of reactivation process was provided. [•] The H2Oθ-Glu pathway is more feasible for aging process. [•] The electrostatic influences of surrounding amino acids were exhibited. [ABSTRACT FROM AUTHOR]

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Due to its prevalent presence, it is critical to clarify the atmospheric fate of acenaphthylene (Ary). In this paper, the reaction mechanism of the gas-phase ozonolysis of Ary was investigated by using quantum chemistry methods. Possible reaction pathways were discussed, and the theoretical results were compared with the available experimental data. The rate constants of the crucial elementary reactions were determined by the Rice–Ramsperger–Kassel–Marcus (RRKM) theory. The main products include secondary ozonide, naphthalene-1,8-dicarbaldehyde, 1,8-naphthalic anhydride, oxaacenaphthylene-2-one, 1-naphthaldehyde, 2-hydroxy-1-naphthaldehyde, and α-hydroxyhydroperoxide. The reaction of the unsaturated cyclo-pentafused ring with O3 is the dominant pathway. The overall rate constant of the O 3 addition reaction is 5.31 × 10 − 16 cm 3 molecule − 1 s − 1 at 298 K and 1 atm. The atmospheric lifetime of Ary determined by O 3 is about 0.75 h. This work provides a comprehensive investigation of the ozonolysis of Ary and should help to understand its atmospheric fate. [ABSTRACT FROM AUTHOR]

Abstract: The ocimene ozonolysis reaction is one of the most important processes for the formation of secondary organic aerosol (SOA). In this paper, molecular orbital theory has been performed for the reaction of ocimene with O3, and the detailed reaction mechanisms of active intermediates with H2O or NO are also presented. The geometry parameters and vibrational frequencies of the stationary points are calculated at the MPWB1K level with the 6-31G(d,p) basis set. Single-point energy calculations are carried out at the MPWB1K/6-311+G(3df,2p) level. On the basis of the quantum chemical information, the Rice–Ramsperger–Kassel–Marcus (RRKM) theory and the canonical variational transition state theory (CVT) with small-curvature tunneling effect (SCT) are used to calculate the rate constants over the temperature range of 200–800 K. The arrhenius formulas of rate constants with the temperature are fitted, which can provide helpful information for the model simulation study. The atmospheric lifetimes of the reaction species are estimated according to the rate constants. [Copyright &y& Elsevier]