Atmospheric chemistry of enols: A theoretical study of the vinyl alcohol OH O2 reaction mechanism

Abstract

Enols are emerging as trace atmospheric components that may play a significant role in the formation of organic acids in the atmosphere. We have investigated the hydroxyl radical (•OH) initiated oxidation chemistry of the simplest enol, vinyl alcohol (ethenol, CH2=CHOH), using quantum chemical calculations and energy-grained master equation simulations. A lifetime of around 4 h was determined for vinyl alcohol in the presence of tropospheric levels of •OH. The reaction proceeds by •OH addition at both the α (66%) and β (33%) carbons of the π-system, yielding the C-centered radicals •CH 2CH(OH)2, and HOCH2C•HOH, respectively. Subsequent trapping by O2 leads to the respective peroxyl radicals...