Mechanism of Oh-Initiated Oxidation of Β-Diketone at the Acidic Droplet Interface

Abstract

Acetylacetone (AcAc) is a typical class of β-diketones, and its atmospheric photooxidation profoundly impact SOA formation. Hence, we performed molecular dynamics simulations to investigate the oxidation of AcAc at the acidic droplet interface. OH-addition to enol-AcAc is favorable to form OH adducts, and for keto-AcAc, H-abstraction pathway is more important to produce alkyl radicals. Subsequent reactions of these intermediates occur via oxidation by O2/NO, isomerization, and decomposition to yield methylglyoxal and acetic acid, which are important SOA precursors. Our results provide an insight into the interfacial chemistry of β-diketones and their influence on the atmospheric environment.

Keywords: Acetylacetone, Air-water interface, Photooxidation, Reaction mechanism, Molecular dynamics simulations