Mechanism for the Oxidation of SO₂ in the Atmosphere by the Intermediate Formed in Ozone-Olefin Reactions Reaction of the Adduct with Water Vapor

Abstract

Oxidation of SO₂ in the ozone-ethylene reaction system was investigated in both the absence and the presence of water vapor by use of HCOOH as an indicator of reaction pathway. In the absence of SO₂, the yield of HCOOH increased with the increase of water vapor. On the contrary, it decreased with water vapor in the presence of SO₂, although absolute yield was much higher than that in the absence of SO₂. These phenomena are in accord with the mechanism we reported previously; the reaction proceeds via formation of the CH₂OO+SO₂ adduct. The ratio of the rate constants, k(Adduct+H₂O)/k(Adduct+SO₂) w as estimated to be 6.0x10-3.