Computational study of H-abstraction reactions from CH3OCH2CH2Cl/CH3CH2OCH2CH2Cl by Cl atom and OH radical and fate of alkoxy radicals.
Multichannel gas-phase reactions of CH3OCH2CH2Cl/CH3CH2OCH2CH2Cl with chlorine atom and hydroxyl radical have been investigated using ab initio method and canonical variational transition-state dynamic computations with the small-curvature tunneling correction. Further energetic information is refined by the coupled-cluster calculations with single and double excitations (CCSD)(T) method. Both hydrogen abstraction and displacement processes are carried out at the same level. Our results reveal that H-abstraction from the -OCH2- group is the dominant channel for CH3OCH2CH2Cl by OH radical or Cl atom, and from α-CH2of the group CH3CH2- is predominate for the reaction CH3CH2OCH2CH2Cl with Cl/OH. The contribution of displacement processes may be unimportant due to the high barriers. The values of the calculated rate constants reproduce remarkably well the available experiment data. Standard enthalpies of formation for reactants and product radicals are calculated by isodesmic reactions. The Arrhenius expressions are given within 220-1200 K. The atmospheric lifetime, ozone depleting potential (ODP), ozone formation potential (OFP), and global warming potential (GWP) of CH3OCH2CH2Cl/CH3CH2OCH2CH2Cl are investigated. Meanwhile, the atmospheric fate of the alkoxy radicals are also researched using the same level of theory. To shed light on the atmospheric degradation, a mechanistic study is obtained, which indicates that reaction with O2is the dominant path for the decomposition of CH3OCH(O•)CH2Cl, the C-C bond scission reaction is the primary reaction path in the consumption of CH3CH(O•)OCH2CH2Cl in the atmosphere.


CONCLUSIONS
Ab initio method and canonical variational transition-state theory are employed to study the kinetic nature of hydrogen abstraction reactions of CH3OCH2CH2Cl/CH3CH2OCH2CH2Cl with Cl atom and OH radical and fate of alkoxy radicals (CH3OCH(O•)CH2Cl/CH3CH(O•)OCH2CH2Cl).
Faculty of Chemistry, Institute of Functional Material Chemistry, Northeast Normal University, 130024, Changchun, People's Republic of China.
Jin-Ting
JT
Ye
Faculty of Chemistry, Institute of Functional Material Chemistry, Northeast Normal University, 130024, Changchun, People's Republic of China.
Feng-Yang
FY
Bai
Faculty of Chemistry, Institute of Functional Material Chemistry, Northeast Normal University, 130024, Changchun, People's Republic of China. panxm460@nenu.edu.cn.
Xiu-Mei
XM
Pan
D000393:Air Pollutants / Q000737:chemistry; D000397:Air Pollution; D000438:Alcohols / Q000737:chemistry*; D002713:Chlorine / Q000737:chemistry*; D003198:Computer Simulation; D006843:Hydrocarbons, Chlorinated / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry* / Q000302:isolation & purification; D017665:Hydroxyl Radical / Q000737:chemistry*; D007700:Kinetics; D008956:Models, Chemical; D008968:Molecular Conformation; D013816:Thermodynamics
D000393:Air Pollutants; D000438:Alcohols; D006843:Hydrocarbons, Chlorinated; C059688:alkoxyl radical; D017665:Hydroxyl Radical; D002713:Chlorine; D006859:Hydrogen
Alkoxy radicals; Hydrochloroether; Rate constant