Kinetic Studies of Oxidation Reactions of Sulfur Compounds: Reaction SO₂ + OH in the Presence Of O₂, and Reaction IO + DMS

Summary

The reactions of atmospheric interest, SO₂ + OH in the presence of O₂ and IO + DMS, have been studied using the discharge flow method with EPR or mass spectrometric analysis of the species. The following rate constants were measured at room temperature:

$$HOS{O_2} + {O_2} \to H{O_2} + S{O_3}(1)\,\,\,\,\,\,\,\,\,\,{k_1} = (3.5\, \pm \,1)\, \times {10^{ - 13}}$$

$$IO + DMS \to products\,\,\,(4)\,\,\,\,\,\,\,\,\,\,\,\,\,\,{k_4}\, = (1.5\, \pm \,0.5)\,\, \times {10^{ - 11}}$$

$$(units\,are\,c{m^3}\,molecul{e^{ - 1}}\,{s^{ - 1}})$$

The value obtained for k₂ confirms the recent hypothesis concerning the HO_X conservation in the gas phase oxidation of SO₂ in the atmosphere. The value obtained for k₄ indicates that IO is a potential candidate for DMS oxidation in marine atmosphere.