OH-Initiated Oxidation of Acetylacetone: Implications for Ozone and Secondary Organic Aerosol Formation

Abstract

Acetylacetone (AcAc) is a common atmospheric oxygenated volatile organic compound due to broad industrial applications, but its atmospheric oxidation mechanism is not fully understood. We investigate the mechanism, kinetics, and atmospheric fate of the OH-initiated oxidation for the enolic and ketonic isomers of AcAc using quantum chemical and kinetic rate calculations. OH addition to enol-AcAc is more favorable than addition to keto-AcAc, with the total rate constant of 1.69 × 10 exp(1935/T) cm molecule s over the temperature range of 200-310 K. For the reaction of the enol-AcAc with OH, the activation energies of H-abstraction are at least 4 kcal mol higher than those of OH-addition, and the rate constants for OH-addition are by 2-3 orders of magnitude higher than those for H-abstraction. Oxidation of AcAc is predicted to yield significant amounts of acetic acid and methylglyoxal, larger than those are currently recognized. A lifetime of less than a few hours for AcAc is estimated throughout the tropospheric conditions. In addition, we present field measurements in Beijing and Nanjing, China, showing significant concentrations of AcAc in the two urban locations. Our results reveal that the OH-initiated oxidation of AcAc contributes importantly to ozone and SOA formation under polluted environments.

Preparation of Composite Filters Based on Porous Coordination Polymers by Using a Vacuum Filtration Method for Highly Efficient Removal of Particulate Matters

“…The two metal centers showed similar coordination configuration, which were coordinated by four oxygen atoms from two individual PTAl igands, two nitrogen atom from L ligands and one oxygen atom from the coordinated water molecules, to forming ap entagonal bipyramid coordination sphere ( Figure S2a). The bond lengths of CdÀOr ange from 2.306(6) to 2.558 (7) ,C d-N vary from 2.319(8) to 2.482 (9) ,w hich were all in accord with the reported values. [25] Along a axis, two adjacent Cd 2 + ions were connected through PTAl igands to form a1 Dc hain with ab identate-chelating coordination fashion ( Figure S2b).…”

“…[6] Currently,various methods have been proposed to eliminate common toxic pollutants( particulate mattersa nd gaseous species). [7] For example, He et al reported bio-based air filters which displayed excellente fficiency for PMs removal and good thermal stability. [8] Seo's group designed the hybrid filter by using power activated carbon injection.…”

Computational studies on the gas phase reaction of methylenimine (CH2NH) with water molecules

“…Geometries of all stationary points were optimized using M06-2X method 31 in conjunction with Pople 6-311++G(3df,3pd) basis set 32 . The M06-2X has been shown to be reliable for handling noncovalent interactions between molecules and widely used to locate the transition states of atmospheric and combustion reaction systems 20,[33][34][35] . The optimized structure of reactants, complexes, intermediates, and transition states (TSs) are shown in Supporting Information Figure S1 and the cartesian coordinates are given in Supporting Information Table S1.…”

Mechanism, kinetics, and environmental assessment of OH‐initiated transformation of CTDE in the atmosphere

“…The above methods have been widely used in investigations of the kinetics of similar systems and verified to be accurate in the calculations of similar reactions. [ 14–18 ] The reactants, products, and the relevant transition states were confirmed by intrinsic reaction coordinate (IRC) calculations. [ 19 ] All the electronic structure calculations were carried out using the Gaussian 09 program package.…”