The kinetics of elementary reactions involving the oxides of sulphur I. The nature of the sulphur dioxide afterglow

Abstract

Studies of the sulphur dioxide afterglow in the products of a weak discharge through sulphur dioxide and argon show that the main active species are O and SO. The chemiluminescent combination of these species produces the sulphur dioxide after glow, the intensity of which is proportional to [O] [SO]. Sulphur monoxide reacts rapidly with nitrogen dioxide SO + NO 2 = SO 2 + NO + 59 kcal/mole. (3) Titration of the sulphur dioxide afterglow with nitrogen dioxide yields the sum of the O and SO concentrations, since reaction (2) is also fast, O + NO 2 = NO + O 2 + 46 kcal/mole. (2) The ratio k 2 / k 3 was found to be 0·67 ± 0·07 at 298°K. Klein & Herron’s (1964) value of k 2 yields k 3 = 5 x 10 12 cm 3 mole -1 s -1 at 298°K.