title: Linear free energy relationships on rate constants for the gas-phase reactions of hydroxyl radicals with PAHs and PCDD/Fs.
abstract: Polyparameter linear free energy relationships (LFERs) on rate constants (kOH) for gas-phase reactions of hydroxyl radicals with polycyclic aromatic hydrocarbons (PAHs) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were developed. Quantum chemical descriptors and partial least squares (PLS) regression were used for model development. Acenaphthylene was found to be an outlier and was excluded in the final model development. The cumulative variance of the dependent variable explained by the PLS components and determined by cross-validation (Q2(cum)), for the optimal model, is 0.97, indicating good robustness and predictive power of the model. The main molecular structural factor governing kOH values of PAHs and PCDD/Fs is molecular ability to donate electrons, as described by the energy of the highest occupied molecular orbital (E(HOMO)), the average of net atomic charges on hydrogen atoms (qH(+)), and the average of net atomic charges on carbon atoms (qC). PAH and PCDD/F molecules with high E(HOMO) and low qH(+) and qC values tend to have high log kOH values. The LFER model indicates the temperature dependence of log kOH is weak.
authors.affiliation: Department of Environmental Science and Technology, Dalian University of Technology, Linggong Road 2, Dalian Liaoning Province 116024, PR China.
authors.forename: Chunli
authors.initials: C
authors.lastname: Yan
authors.forename: Jingwen
authors.initials: J
authors.lastname: Chen
authors.forename: Liping
authors.initials: L
authors.lastname: Huang
authors.forename: Guanghui
authors.initials: G
authors.lastname: Ding
authors.forename: Xiaoying
authors.initials: X
authors.lastname: Huang
mesh_terms: D001572:Benzofurans / Q000737:chemistry*; D000072338:Dibenzofurans, Polychlorinated; D005740:Gases / Q000737:chemistry; D017665:Hydroxyl Radical / Q000737:chemistry*; D016014:Linear Models; D008956:Models, Chemical; D000072317:Polychlorinated Dibenzodioxins / Q000031:analogs & derivatives* / Q000737:chemistry; D011084:Polycyclic Aromatic Hydrocarbons / Q000737:chemistry*; D011237:Predictive Value of Tests; D013329:Structure-Activity Relationship; D013696:Temperature
chemical_list: D001572:Benzofurans; D000072338:Dibenzofurans, Polychlorinated; D005740:Gases; D000072317:Polychlorinated Dibenzodioxins; D011084:Polycyclic Aromatic Hydrocarbons; D017665:Hydroxyl Radical