DETERMINATION OF RATE CONSTANTS FOR THE REACTIONS OF THE CH2SH RADICAL WITH O-2, O-3, AND NO2 AT 298-K

Abstract

AbstractCH2SH radicals were produced by the reaction of F atoms with an excess of CH3SH and detected mass spectrometrically at m/e 47 using an electron energy of 9.5 eV. Rate constants for the reactions of CH2SH with the oxidants O2 (k1), O3 (k2) and NO2 (k3) at 298 K were determined by measuring the decay of the radical in the presence of excess oxidants. The following results were obtained: magnified imageThe rate constant for the reaction (4) F + CH3SH → products was determined to be k1 = (2.4 ± 0.4)·10−10 cm3 molecule−1 s−1. The branching into the channels (4a) F + CH3SH → CH2SH + HF and (4b) F + CH3SH → CH3S + HF was investigated by using CD3SH, and k4a/k4 = 0.6 ± 0.1 was obtained.