Accretion product formation in the self-reaction of ethene-derived hydroxy peroxy radicals

Abstract

In this study we revisit one of the simplest reactions: the self-reaction of the ethene-derived hydroxyperoxy radical formed via sequential addition of ˙OH and O2 to ethene. Previous studies of this reaction suggested that the branching to ‘accretion products’, compounds containing the carbon backbone of both reactants, was minimal. Here, CF3O− GC-CIMS is used to quantify the yields of ethylene glycol, glycolaldehyde, a hydroxy hydroperoxide produced from , and a C4O4H10 accretion product. These experiments were performed in an environmental chamber at 993 hPa and 294 K. We provide evidence that the accretion product is likely dihydroxy diethyl peroxide (HOC2H4OOC2H4OH 00000000 00000000 00000000 00000000 11111111 00000000 11111111 00000000 00000000 00000000 ROOR) and forms in the gas-phase with a branching fraction of 23 ± 5%. We suggest a new channel in the chemistry leading directly to the formation of (together with glycolaldehyde and an alkoxy radical). Finally, by varying the ratio of the formation rate of and in our chamber, we constrain the ratio of the rate coefficient for the reaction of to that of and find that this ratio is 0.22 ± 0.07, consistent with previous flash photolysis studies.