Atmospheric chemistry of CHF2CF2OCH2CF3: Reactions with Cl atoms, fate of CHF2CF2OC•HCF3 radical, formation of OH radical and Criegee Intermediate

• Published in: Atmospheric environment (1994) 2020-12, Vol.242, p.117805, Article 117805
• Main Authors: Lily, Makroni, Baidya, Bidisha, Wang, Wenliang, Liu, Fengyi, Chandra, Asit K.
• Format: Article
• Language: English
• Subjects: CHF2CF2OCHO; Cl atoms; Fluorinated Criegee intermediate; Hydrofluoroethers; M06-2X; OH formation; Variational transition-state theory
• ISSN: 1352-2310; 1873-2844
• DOI: 10.1016/j.atmosenv.2020.117805

The kinetics and mechanism for hydrogen abstraction reactions of CHF2CF2OCH2CF3 with Cl atoms were studied using the DFT-based M06-2X/6-311++G(d,p) quantum chemical method. The thermal rate coefficients for H-abstraction reactions were evaluated by canonical variational transition state theory along with the small curvature tunneling correction over the temperature range of 200–1000 K. A three-parameter model equation has been proposed to describe the temperature variation of rate coefficient as k(CHF2CF2OCH2CF3+Cl) = 5.24 × 10−22T3.2exp(-580/T)(in cm3 molecule−1s−1). Atmospheric lifetime of CHF2CF2OCH2CF3 is estimated to be 3.10 years and global warming potentials at the 100-year time horizon is calculated as 601. The atmospheric fate of generated CHF2CF2OC•HCF3 radical are reported. The rate coefficient values for the reaction of important degradation products like CHF2CF2OCHO and CHF2CF2OOH with OH/Cl are also reported for the first time. Production of OH radicals from the unimolecular decomposition of CHF2CF2OC(OO•)HCF3 peroxy radical and the possible formation of Fluorinated Criegee Intermediate from self-reaction of RO2 radicals are discussed. [Display omitted] •First detailed theoretical studies on the kinetics and mechanism of CHF2CF2OCH2CF3+Cl reaction.•Calculated rate coefficients are in good agreement with the experimental values.•Rate coefficient of CHF2CF2OCHO and CHF2CF2OOH with OH radical and Cl atoms were reported for the first time.•Formation of OH radical and CF2O2 Criegee Intermediate from self-reactions of CHF2O2• radicals were reported.