Elementary reaction path on polychlorinated biphenyls formation from polychlorinated benzenes in heterogeneous phase using ab initio molecular orbital calculation
| Autor: | Junichi Kato, Akio Fuwa, Mitsuhito Hirota, Hiromitsu Takashita |
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| Rok vydání: | 2003 |
| Předmět: |
Biphenyl
Reaction mechanism Environmental Engineering Bond strength Chemistry Health Toxicology and Mutagenesis Public Health Environmental and Occupational Health Ab initio Free-radical reaction General Medicine General Chemistry Pollution Polychlorinated Biphenyls Dissociation (chemistry) Catalysis chemistry.chemical_compound Models Chemical Computational chemistry Elementary reaction Environmental Chemistry Molecular orbital Environmental Pollutants Copper Forecasting |
| Zdroj: | Chemosphere. 50(4) |
| ISSN: | 0045-6535 |
| Popis: | We have investigated the elementary reaction path on the 3,3′,4,4′,5,5′-hexachlorinated biphenyl (HxCB) formation from two 1,2,3,5-tetrachlorobenzenes (TCBz) and the catalytic role of copper on this formation using ab initio molecular orbital calculation. The elementary reaction path on the 3,3′,4,4′,5,5′-HxCB formation from two 1,2,3,5-TCBzs has been shown to occur as follows: Step 1––the dissociation of Cl atom substituted at 5-position in 1,2,3,5-TCBz, Step 2––the association between Cl atom substituted at 5-position in another 1,2,3,5-TCBz and the Cl radical formed in Step 1, Step 3––the elimination of Cl2 molecule from the intermediate species formed in Step 2, and Step 4––the 3,3′,4,4′,5,5′-HxCB formation from the direct condensation of two 1,2,3-trichlorophenyl radicals formed in Step 1 and Step 3. The geometric factor, which decides the reactivity of this formation, is the C–Cl bond strength of 1,2,3,5-TCBz. The catalytic roles of copper are to stabilize the total energy in the adsorption of 1,2,3,5-TCBz onto the copper surface and to weaken the C–Cl bond strength due to the charge transfer from the 1,2,3,5-TCBz to the copper surface. Moreover, we have achieved the prediction of the minimum energy path on the formation of non- and mono-ortho polychlorinated biphenyls congeners for which TEFs have been determined. |
| Databáze: | OpenAIRE |
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