Reactivity of neonicotinoid insecticides with carbonate radicals
The reaction of three chloronicotinoid insecticides, namely Imidacloprid (IMD), Thiacloprid (THIA) and Acetamiprid (ACT), with carbonate radicals (CO·₃⁻) was investigated. The second order rate constants (4 ± 1) × 10⁶, (2.8 ± 0.5) × 10⁵, and (1.5 ± 1) × 10⁵ M⁻¹ s⁻¹ were determined for IMD, THIA and...
Guardado en:
| Autores principales: | , , , , , , |
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| Formato: | Articulo |
| Lenguaje: | Inglés |
| Publicado: |
2012
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| Materias: | |
| Acceso en línea: | http://sedici.unlp.edu.ar/handle/10915/128005 |
| Aporte de: |
| Sumario: | The reaction of three chloronicotinoid insecticides, namely Imidacloprid (IMD), Thiacloprid (THIA) and Acetamiprid (ACT), with carbonate radicals (CO·₃⁻) was investigated. The second order rate constants (4 ± 1) × 10⁶, (2.8 ± 0.5) × 10⁵, and (1.5 ± 1) × 10⁵ M⁻¹ s⁻¹ were determined for IMD, THIA and ACT, respectively. The absorption spectra of the organic intermediates formed after CO·₃⁻ attack to IMD is in line with those reported for α-aminoalkyl radicals. A reaction mechanism involving an initial charge transfer from the amidine nitrogen of the insecticides to CO·₃⁻ is proposed and further supported by the identified reaction products. The pyridine moiety of the insecticides remains unaffected until nicotinic acid is formed. CO·₃⁻ radical reactivity towards IMD, ACT, and THIA is low compared to that of HO• radicals, excited triplet states, and ¹O₂, and is therefore little effective in depleting neonicotinoid insecticides. |
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