Gas-phase organic reactions of the atomic oxygen radical cation

Reactivity of ground-state oxygen radical cation, 0(center dot+)(S-4), has been studied with several organic compounds for the first time. Rate constants and product distributions have been measured for the ion-neutral reactions of 0(center dot+) with acetaldehyde, acetic acid, acetone, dimethyl ether, methanol, and methyl formate at 300 K in a flowing-afterglow-selected ion flow tube (FA-SIFT). The reactions observed proceed efficiently, occurring above 50% of the collision rate in each case. We observed highly exothermic charge transfer reactions which lead to dissociation in some cases. Other interesting trends in reactivity include attack on methyl groups, and for some reactions, 0(center dot+) replaces the methyl radical. (C) 2013 Elsevier B.V. All rights reserved.