Gibbs Free Energy of Formation of Chlordecone and Potential Degradation Products: Implications for Remediation Strategies and Environmental Fate
Résumé
Chlordecone (C10Cl10O; CAS number 143-50-0) has been used extensively as an organochlorine insecticide, but is nowadays banned under The Stockholm Convention on Persistent Organic Pollutants (POPs). A search for chlordecone respiring organisms and choosing between reductive versus oxidative remediation tools and strategies to clean up chlordecone polluted environments would benefit from the availability of Gibbs free energy data of chlordecone and its potential dechlorination products. Presently such data are not available. Polycyclic "cage" molecules of which chlordecone is an example contain considerable strain energy. It is not a priory clear how this affects thermodynamic properties of the chlorinated members of this unique class of compounds, and to what extent redox potentials for the halogenated congeners are different from those of other aliphatic and aromatic organohalogens. We have performed ab initio quantum chemical calculations to estimate ΔfHmo and ΔfGmo values of chlordecone and selected dechlorination products, and used these data to calculate their Gibbs free energy and redox potential. With redox potentials in the range of 336 to 413 mV chlordecone has an Eo' value similar to that of other organochlorines. The results indicate that there are no thermodynamic reasons why chlordecone respiring or fermenting organisms should not exist.
Domaines
Bactériologie
Origine : Fichiers produits par l'(les) auteur(s)
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