Temperature-Dependent Kinetic Study of the Reactions of Hydrogen Atoms with H2S and C2H4S.

A discharge-flow reactor combined with modulated molecular beam mass spectrometry technique was employed to determine the rate constants of H-atom reactions with hydrogen sulfide and thiirane. The rate constants for both reactions were determined at a total pressure of 2 Torr from 220 to 950 K under pseudo-first-order conditions by monitoring either consumption of H atoms in excess of H2S (C4H4S) or the molecular species in excess of atomic hydrogen. For H + H2S reaction, a suggested previously strong curvature of the Arrhenius plot was confirmed: kl = 8.7 × 10-13 × (T/298)2.87 × exp(-125/T) cm3 molecule-1 s-1 with a conservative uncertainty of 15% at all temperatures. Non-Arrhenius behavior was also observed for the reaction of H-atom with C2H4S, with the experimental rate constant data being best fitted to a sum of two exponential functions: k2 = 1.85 × 10-10 exp(-1410/T) + 4.17 × 10-12 exp(-242/T) cm3 molecule-1 s-1 with an independent of temperature uncertainty of 15%.