KINETICS OF THE REACTIONS OF THE IO RADICAL WITH DIMETHYL SULFIDE, METHANETHIOL, ETHYLENE, AND PROPYLENE

The reactions of IO radicals with CH3SCH3, CH3SH, C2H4, and C3H6 have been studied using the discharge flow method with direct detection of IO radicals by mass spectrometry. The absolute rate constants obtained at 298 K are the following: IO + CH3SCH3 --> products (1): k1 = (1.5 +/- 0.2) x 10(-14); IO + CH3SH --> products (2): k2 = (6.6 +/- 1.3) x 10(-16); IO + C2H4 --> products (3): k3 < 2 x 10(-16); IO + C3H6 --> products (4): k4 < 2 x 10(-16) (units are cm3 molecule-1 s-1). CH3S(O)CH3 and HOI were found as products of reactions (1) and (2), respectively. The present lower value of k1 compared to our previous determination is discussed.