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Mechanistic and kinetic study on the reaction of the·Cl‐initiated atmospheric degradation of CFCl 2 O 2
Author(s) -
Zhang Yunju,
Bing He,
Song Ruojing
Publication year - 2021
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.4130
Subject(s) - chemistry , reaction rate constant , singlet state , reaction mechanism , rrkm theory , density functional theory , kinetic energy , basis set , singlet oxygen , computational chemistry , photochemistry , kinetics , excited state , atomic physics , oxygen , physics , quantum mechanics , organic chemistry , catalysis
The gas‐phase reaction between CFCl 2 O 2 and Cl was researched by means of quantum chemical methods. B3LYP method with the 6‐311++G(d,p) basis set were employed to obtain the geometrical parameters of all stationary points including in the reaction. The singlet and triplet potential energy surfaces (PESs) were characterized at the Multicoefficient Correlation Method (BMC‐CCSD)//B3LYP/6‐311++G(d,p) level. Addition/elimination and S N 2 displacement reaction mechanisms were identified on the singlet PES, and only S N 2 displacement reaction mechanism was located on the triplet PES. The dominant reaction takes place on the singlet PES, and the primary pathways are CFCl 2 O 2 + Cl → IM1 (CFCl 2 OOCl) → P1 (ClClO + CFClO) and CFCl 2 O 2 + Cl → IM1 (CFCl 2 OOCl) → IM3 (CFCl (OCl) 2 ) → P2 (ClOCl + CFClO). Rice–Ramsperger–Kassel–Marcus (RRKM) theory was used to calculate rate constants, which is consistent with the experimental data. The atmospheric lifetime of CFCl 2 O 2 in Cl is about 4.9 h in the marine boundary layer. Time dependent density functional theory (TDDFT) computations imply that IM1 (CFCl 2 OOCl), IM2 (CFCl 2 OClO), IM3 (CFCl (OCl) 2 ), IM4 (FOCCl 2 OCl) will photolyze under the sunlight.