Computational study on the relative stability and formation distribution of 76 polychlorinated naphthalene by density functional theory

Zhai, Zhicai; Wang, Zunyao

doi:10.1016/j.theochem.2005.03.029

Cited by 33 publications

(28 citation statements)

References 13 publications

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“…The larger charge difference between the C atoms ) of 75 polychlorinated naphthalenes using DFT that were heavily dependent on the number and position of the chlorine atoms. 25 In this study, the calculated TE, ΔH f 0 , and ΔG f 0 of CN-73 are lower than those of CN-74. The isomers that featured chlorine atoms at either set of positions i.e., 1 and 8, or 4 and 5 were determined as nonstable.…”

Section: ■ Results and Discussionmentioning

confidence: 51%

“…27 The TE, ΔH f 0 , and ΔG f 0 of CN-66/67 and CN-52/60 were the lowest among those obtained for the HxCNs and PeCNs isomers. 25 On the basis of the steric effect viewpoint, the isomers with fewer chlorine atoms substituted at the orthopositions were more stable. As observed in Figure 2b and c, the content of the thermodynamically stabilized CN-66/67 amounted to ∼91.5% of the total content of the HxCN isomers and CN-52/60 amounted to ∼81.1% of the total content of PeCN isomers at a reaction time of 5 min.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Thermal Degradation of Octachloronaphthalene over As-Prepared Fe₃O₄ Micro/Nanomaterial and Its Hypothesized Mechanism

Lü

Zhang

et al. 2014

Environ. Sci. Technol.

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Decomposition of octachloronaphthalene (CN-75) featuring fully substituted chlorines was investigated over asprepared Fe 3 O 4 micro/nanomaterial at 300°C. It conforms to pseudo-first-order kinetics with k obs = 0.10 min −1 as comparable to that of hexachlorobenzene and decachlorobiphenyl. Analysis of the products indicates that the degradation of CN-75 proceeds via two competitive hydrodechlorination and oxidation pathways. The onset of hydrodechlorination producing lower chlorinated naphthalenes (CNs) is more favored on α-position than β-position. Higher amounts of CN-73, CN-66/67, CN-52/60, and CN-8/11 isomers were found, while small content difference was detected within the tetrachloronaphthalene and trichloronaphthalene homologues, which might be attributed to lower energy principle and steric effects. The important hydrodechlorination steps, leading to CN-73 ≫ CN-74 in two heptachloronaphthalene isomers contrary to that in technical PCN-mixtures, were specified by calculating the charge of natural bond orbitals in CN-75 and the energy of two heptachloronaphthalene radicals. On the basis of the molecular electrostatic potential of CN-75, the nucleophilic O 2− , and eletrophilic O 2 − and O − , present on the Fe 3 O 4 surface, might attack the carbon atom and π electron cloud of naphthalene ring, producing naphthol species with Mars−van Krevelen mechanism, and formic and acetic acids.

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Section: ■ Results and Discussionmentioning

confidence: 51%

Section: ■ Results and Discussionmentioning

confidence: 99%

Thermal Degradation of Octachloronaphthalene over As-Prepared Fe₃O₄ Micro/Nanomaterial and Its Hypothesized Mechanism

Lü

Zhang

et al. 2014

Environ. Sci. Technol.

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“…Congeners such as CN-23, CN-46, and CN-59 have relatively high Gibbs free energies compared with other congeners with the same numbers of chlorine atoms, and therefore generally been found at lower concentrations than other congeners [42]. However, high CN-23, CN-46, and CN-59 concentrations have been found in samples collected during thermal processes and in samples from the natural environment [42][43][44]. CN-23, CN-46, and CN-59 made larger contributions to the PCN patterns in the kiln head zone samples from Series 1 than to the patterns in the other Series 1 samples.…”

Section: Congener Profiles Of Pcns In the Solid Samplesmentioning

confidence: 99%

Variations and factors that influence the formation of polychlorinated naphthalenes in cement kilns co-processing solid waste

Jin

Zhan

Liu

et al. 2016

Journal of Hazardous Materials

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h i g h l i g h t s• PCN destruction efficiencies of cement kilns were derived.• Factors influencing PCN variation and formation were identified.• Major pathways for PCN formation and decomposition in cement kiln were discussed.• PCN indicators for sources involved with coal burning were proposed. a r t i c l e i n f o b s t r a c tPilot studies of unintentionally produced pollutants should be performed before waste being coprocessed in cement kilns. Polychlorinated naphthalene (PCN) formation and emission from cement kilns co-processing sorted municipal solid waste, sewage sludge, and waste acid, however, have not previously been studied. Here, PCNs were analyzed in stack gas samples and solid samples from different stages of three cement production runs. PCN destruction efficiencies were higher when waste was coprocessed (93.1% and 88.7% in two tests) than when waste was not co-processed (39.1%), so co-processing waste would not increase PCN outputs. The PCN concentrations were higher in particle samples from the C1 preheater and stages at back end of kiln than in particle samples from other stages, suggesting that cyclone preheater and back end of kiln should be focused for controlling PCN emissions. Besides that, based on the variation of PCN concentrations and corresponding operating conditions in different stages, the temperature, feeding materials, and chlorine content were suggested as the main factors influencing PCN formation. The PCN homologue and congener profiles suggested chlorination and dechlorination were the main PCN formation and decomposition pathways, and congeners CN-23, CN-46, and CN-59 appear to be appropriate indicators of PCNs emitted from coal-burning sources.

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“…It has been suggested, from theoretical calculations and experimental studies, that chlorination occurs much more easily at the b positions than at the a positions of a PCN molecule (Luijk et al, 1994;Zhai and Wang, 2005;Jansson et al, 2008). The main difference between the PCN congener patterns found in samples from the head and back ends of the kilns was that…”

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confidence: 99%

Distributions, profiles and formation mechanisms of polychlorinated naphthalenes in cement kilns co-processing municipal waste incinerator fly ash

et al. 2016

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Computational study on the relative stability and formation distribution of 76 polychlorinated naphthalene by density functional theory

Cited by 33 publications

References 13 publications

Thermal Degradation of Octachloronaphthalene over As-Prepared Fe₃O₄ Micro/Nanomaterial and Its Hypothesized Mechanism

Thermal Degradation of Octachloronaphthalene over As-Prepared Fe₃O₄ Micro/Nanomaterial and Its Hypothesized Mechanism

Variations and factors that influence the formation of polychlorinated naphthalenes in cement kilns co-processing solid waste

Distributions, profiles and formation mechanisms of polychlorinated naphthalenes in cement kilns co-processing municipal waste incinerator fly ash

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Computational study on the relative stability and formation distribution of 76 polychlorinated naphthalene by density functional theory

Cited by 33 publications

References 13 publications

Thermal Degradation of Octachloronaphthalene over As-Prepared Fe3O4 Micro/Nanomaterial and Its Hypothesized Mechanism

Thermal Degradation of Octachloronaphthalene over As-Prepared Fe3O4 Micro/Nanomaterial and Its Hypothesized Mechanism

Variations and factors that influence the formation of polychlorinated naphthalenes in cement kilns co-processing solid waste

Distributions, profiles and formation mechanisms of polychlorinated naphthalenes in cement kilns co-processing municipal waste incinerator fly ash

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Thermal Degradation of Octachloronaphthalene over As-Prepared Fe₃O₄ Micro/Nanomaterial and Its Hypothesized Mechanism

Thermal Degradation of Octachloronaphthalene over As-Prepared Fe₃O₄ Micro/Nanomaterial and Its Hypothesized Mechanism