The Reactions of H Atoms with H2S and COS

The kinetics of the reactions of H atoms with H₂S and with COS were measured at 298deg;K in a flow system using mass-spectrometric detection. The rate constants were found to be 3.8 × 10^?13 and 2.2 × 10^?14 cm₃ part^?1 sec^?1, respectively, with an estimated accuracy of 25%. At high flow rates of H₂S, 0.5 molecules of H₂S are consumed per H atom originally present. At all flow rates of COS, H₂S is a major product, CO production equals COS consumption, and 0.5 molecules of COS are consumed per H atom. The results are consistent with the reaction HS + HS → H₂S + S being the dominant process for thiyl radicals, and evidence is presented to indicate that its reaction rate is close to collisional frequency.