Quantum chemical study on ·Cl-initiated degradation of ethyl vinyl ether in atmosphere

Abstract

ABSTRACT A theoretical investigation on oxidation reaction of ethyl vinyl ether (EVE) and .Cl are carried out in this paper. By employing M06-2x/6-31 + g(d,p)//6-311++g(3df,2p) method, complex reaction mechanisms are assumed on the basis of thermodynamic data. All the .Cl-addition reactions are dominant channels. The corresponding major products, such as ethyl formate, acetaldehyde and several chloro compounds, are generated from .Cl-addition to double bond of EVE. These products play an important role in the formation of secondary organic aerosol. By employing MESMER grogram, rate coefficients of the primary reactions are computed in the temperature range of 200–400 K and the pressure range of 500–2000 Torr. Combined with the kinetic data and temperature, an Arrhenius equation is fitted as k EVE+Cl = 1.54 × 10−10 exp (121.9/T). Also, the rate constant at 298 K and 760 Torr is calculated to be 2.17 × 10−10 cm3 molecule−1 s−1. Furthermore, the atmospheric lifetime of EVE with respect to .Cl is estimated to be 4.3–11.9 h in different regions. The short lifetime indicates that ·Cl-initiated oxidation is competitive in the degradation of EVE in some special areas. This work could confirm the experimental investigation and serve as the supplement of our previous theoretical studies.