Reductive deactivation of some s-triazine herbicides: Prometryne, desmetryne and terbutryne
| Autor: | Galvin Rrafael Marin, Mellado Jose Miguel Rodriguez, Higuera Maria Jose |
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| Jazyk: | angličtina |
| Rok vydání: | 2002 |
| Předmět: | |
| Zdroj: | Journal of the Serbian Chemical Society, Vol 67, Iss 6, Pp 381-392 (2002) |
| Druh dokumentu: | article |
| ISSN: | 0352-5139 1820-7421 |
| DOI: | 10.2298/JSC0206381G |
| Popis: | The electrochemical behaviour (DC and DPpolarography) of the methylthio-bis(alkylamino) s-triazine herbicides prometryne, desmetryne and terbutryne on mercury electrodes has been studied in the acidity range 2.25MH2SO4 to pH 6.5. Two two-electron irreversible reduction processes were found, complicated with adsorption. At pH values higher than the protonation pKof the triazine ring (ca. 4), this protonation reaction preceded the reduction processes. Reduction mechanisms are proposed for pH < pK and pH > pK. The products obtained in the electroreduction of dilute solutions of the above herbicides show a lower toxicological effect than that of the original compounds (lower aromatic character and cleavage of the –SCH3 group). Thus electrochemical deactivation at pH 3.5 and at potentials around –1.10 V (vs. the Ag/AgCl/KClsat electrode) can be a valid method to deactivate these molecules. Finally, the reductive route can be an alternative environmental degradative process in waters under strong reductive conditions, with pH values equal or lower than 3.5 pH-units, and rich in carbonaceous materials on clays. In these ambients oxidative photolytic detoxification of herbicides cannot occur. |
| Databáze: | Directory of Open Access Journals |
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