Tropospheric chemical degradation of vinyl and allyl acetate initiated by Cl atoms under high and low NOx conditions

Abstract

The products of the reactions of Cl atoms with vinyl acetate (VA) and allyl acetate (AA) have been investigated in a 1080 L chamber using in situ FTIR. The experiments were performed at 296 K and atmospheric pressure of synthetic air in the presence and in the absence of NOx. For the reaction of Cl with VA in the presence of NOx formic acetic anhydride, acetic acid and formyl chloride are the major reaction products. In the absence of NOx, the yields of these products are significantly reduced and formation of the carbon-chain-retaining compound CH3C(O)OC(O)CH2Cl is observed. For the reaction of Cl with AA in the presence of NOx acetoxyacetaldehyde and formaldehyde were observed as the main products. In contrast, without NOx, the observations support that the major reaction pathway is the formation of the carbon-chain-retaining compound CH3C(O)OCH2C(O)CH2Cl. The reaction mechanisms leading to the products are discussed. The formation of the high yields of formyl chloride and formaldehyde in the reactions of Cl with VA and AA, respectively, are at odds with currently accepted mechanistic pathways.