Rate coefficients for the gas-phase reaction of OH radicals with dimethyl sulfide:: temperature and O2 partial pressure dependence

Rate coefficients for the gas-phase reaction of hydroxyl (OH) radicals with dimethyl sulfide (CH3SCH3, DMS) have been determined using a relative rate technique. The experiments were performed under different conditions of temperature (250-299 K) and O-2 partial pressure (similar to 0 Torr O-2-380 Torr O-2), at a total pressure of 760 Torr bath gas (N-2 + O-2), in a 336 1 reaction chamber, using long path in situ Fourier transform (FTIR) absorption spectroscopy to monitor the disappearance rates of DMS and the reference compounds (ethene, propene and 2-methylpropene). OH was produced by the photolysis of H2O2. The following Arrhenius expressions adequately describe the rate coefficients as a function of temperature (units are cm 3 molecule(-1) s(-1)): k = (1.56 +/- 0.20) x 10(-12) exp[(369 +/- 27)/T], for similar to 0 Torr O-2; (1.31 +/- 0.08) x 10(-14) exp[(1910 +/- 69)/T], for 155 Torr O-2; (5.18 +/- 0.71) x 10(-14) exp[(1587 +/- 24)/T], for 380 Torr O-2. The results are compared with previous investigations.