OBSERVATION OF DMSO AND CH3S(O)OH FROM THE GAS-PHASE REACTION BETWEENDMS AND OH

Products and mechanisms have been investigated for the reactions betwe en dimethylsulfide (DMS) and dimethylsulfoxide (DMSO) and the hydroxyl radical (OH) in the presence of NOx. All of the experiments were perf ormed in a 480 L reaction chamber, applying Fourier transform infrared spectroscopy (FT-IR) and ion chromatography as the analytical techniq ues. In addition to the sulfur containing products that are known to b e produced from the gas phase reaction between DMS and OH (SO2, dimeth ylsulfone, methylsulfonyl peroxynitrate, methanesulfonic acid, H2SO4), DMSO and methanesulfinic acid (CH3S(O)OH) were also observed as produ cts. Only SO2, DMSO(2) and methylsulfonyl peroxynitrate were found as sulfur containing products in the reaction between DMSO and OH. Based on these new results we propose a mechanism for the atmospheric oxidat ion of DMS and DMSO by OH radical.