Formation pathways of DMSO from DMS‐OH in the presence of O2 and NOx: A theoretical study

The relative importance of the reaction pathways and thus the product yields in the dimethyl sulfide (DMS) degradation scheme initiated by the hydroxyl (OH) radical has been said to be influenced by the content of nitrogen oxides (NOx) in chamber experiments. In this study, ab initio and density functional electronic structure calculations of all the possible reaction pathways corresponding to the reaction process initiated by DMS‐OH + oxygen (O2), leading to the formation of the dimethyl sulfoxide (DMSO) product in the presence of NOx (NO and NO2), are carried out for the first time. The results for the different pathways are compared with the objective of inferring their kinetic relevance in the laboratory experiments that measure DMSO formation yields. Our theoretical results clearly show the existence of NOx‐dependent pathways leading to the formation of DMSO in addition to O2‐dependent channels. So then, NOx‐containing conditions would have to modify the relative importance of the addition channel in the DMS oxidation process. © 2008 Wiley Periodicals, Inc. J Comput Chem, 2009

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