Elucidation of fipronil photodegradation pathways.
Elucidation of fipronil photodegradation pathways.
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DOI：
10.1021/jf9913007
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发表时间：
2000-09
影响因子：
6.1
通讯作者：
K. Ngim;S. Mabury;D. Crosby
中科院分区：
文献类型：
--
作者：
K. Ngim;S. Mabury;D. Crosby
苯基吡唑类杀虫剂氟虫腈(I)在水溶液中光解生成脱硫产物(II)。然而，尚未解决中间氧化为砜中间体(III)的必要性，并且尚未鉴定II的光降解产物。使用 GC-MS、HPLC-UV/vis、电喷雾 MS、(19)F NMR 和 GC-TSD，我们的目标是表征 I 的光降解途径，这将阐明 III 的作用，识别 II 的产物，并解释先前研究中的不平衡质量帐户。研究结果表明，II 是由 I 直接通过光化学作用形成的，III 具有更高的稳定性（t(1/2) 112 h），这证实了这一点，并且 I 连续氧化为 III，然后形成磺酸盐 (IV)，构成了第二条途径。化合物II经历光脱氯、三氟甲基取代氯和吡唑环裂解。这项工作对于了解环境中新型苯基吡唑类农药的光化学具有重要意义。
The phenylpyrazole insecticide fipronil (I) photolyzes to its desthio product (II) in aqueous solution. However, the necessity of an intervening oxidation to a sulfone intermediate (III) has not been resolved, and the photodegradation products of II have not been identified. Using GC-MS, HPLC-UV/vis, electrospray MS, (19)F NMR, and GC-TSD, our objective was to characterize the photodegradation pathways of I, which would clarify the role of III, identify products of II, and explain unbalanced mass accounts in previous studies. Findings showed that II is formed directly and photochemically from I, confirmed by the greater stability of III (t(1/2) 112 h), and that successive oxidations of I to III and then a sulfonate (IV) comprise a second pathway. Compound II underwent photodechlorination, substitution of chlorine by trifluoromethyl, and pyrazole ring cleavage. This work is significant to understanding the photochemistry of novel phenylpyrazole pesticides in the environment.