Evaluating Computational and Structural Approaches to Predict Transformation Products of Polycyclic Aromatic HydrocarbonsShow others and affiliations
2019 (English)In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 53, no 3, p. 1595-1607Article in journal (Refereed) Published
Abstract [en]
Polycyclic aromatic hydrocarbons (PAHs) undergo transformation reactions with atmospheric photochemical oxidants, such as hydroxyl radicals (OH center dot), nitrogen oxides (NOx), and ozone (O-3). The most common PAH-transformation products (PAH-TPs) are nitrated, oxygenated, and hydroxylated PAHs (NPAHs, OPAHs, and OHPAHs, respectively), some of which are known to pose potential human health concerns. We sampled four theoretical approaches for predicting the location of reactive sites on PAHs (i.e., the carbon where atmospheric oxidants attack), and hence the chemoselectivity of the PAHs. All computed results are based on density functional theory (B3LYP/6-31G(d) optimized structures and energies). The four approaches are (1) Clar's prediction of aromatic resonance structures, (2) thermodynamic stability of all OHPAH adduct intermediates, (3) computed atomic charges (Natural Bond order, ChelpG, and Mulliken) at each carbon on the PAH, and (4) average local ionization energy (ALIE) at atom or bond sites. To evaluate the accuracy of these approaches, the predicted PAH-TPs were compared to published laboratory observations of major NPAH, OPAH, and OHPAH products in both gas and particle phases. We found that the Clar's resonance structures were able to predict the least stable rings on the PAHs but did not offer insights in terms of which individual carbon is most reactive. The OHPAH adduct thermodynamics and the ALIE approaches were the most accurate when compared to laboratory data, showing great potential for predicting the formation of previously unstudied PAH-TPs that are likely to form in the atmosphere.
Place, publisher, year, edition, pages
American Chemical Society (ACS), 2019. Vol. 53, no 3, p. 1595-1607
National Category
Environmental Sciences
Identifiers
URN: urn:nbn:se:oru:diva-72760DOI: 10.1021/acs.est.8b05198ISI: 000458220600058PubMedID: 30571095Scopus ID: 2-s2.0-85061030676OAI: oai:DiVA.org:oru-72760DiVA, id: diva2:1291428
Note
Funding Agencies:
National Institute of Environmental Health Sciences (NIEHS) P30ES00210 P42ES016465
National Institutes of Health (NIH)
National Science Foundation (NSF) AGS-1411214
OSU Stone Family
NSF CHE-1352663
Johnson Research Fellowship
OSU Department of Chemistry through the Dorothy Ramon Barnes Fellowship
NIEHS T32ES007060
2019-02-252019-02-252019-02-25Bibliographically approved