Computational study on the mechanism and kinetics of Cl-initiated oxidation of vinyl acetate

A comprehensive theoretical study of chlorine-initiated atmospheric oxidation mechanism of vinyl acetate (VAC, CH2CHOC(O)CH3) has been performed by using MPWB1K/6-311 + G(3df,2p)//MPWB1K + G(d,p). Two reaction types (Cl-addition and H-abstraction) and the subsequent reactions for the primary intermediates (IM1 and IM2) have been proposed in the presence of O2 and NO. The calculated results show that the Cl addition–elimination mechanism dominates the reaction between vinyl acetate and Cl. For the Cl addition reactions, the most energetically favorable pathway is the Cl addition to the terminal carbon atom. H-abstraction pathways are not expected to play an important role in the final products formation. The major possible degradation products have been identified. The rate constants and branching ratios of the main reaction channels have been obtained over a wide range of temperatures and pressures by using master equation (ME) calculations. The total rate constants are dependent on pressure and temperature over the whole study range (0.1–10,000 Torr and 200–1000 K). The atmospheric lifetime of vinyl acetate is estimated.