丁烯氟虫腈光降解反应过程及机理

摘要

考察了乙腈/水混合溶液中丁烯氟虫腈的光解速率及水体中主要溶解性物质对其光解的影响,通过产物鉴定及模拟计算判定了丁烯氟虫腈光降解反应机理.结果表明,模拟日光下丁烯氟虫腈快速发生光降解,纯水中反应半衰期为17.34 min.腐殖酸通过竞争光吸收来抑制丁烯氟虫腈的光解,NO3-和Cl-对其光解无影响.丁烯氟虫腈光解反应位点位为亚砜基团上的硫原子,主要产物为脱硫化物(MW 442.0),砜化物(MW 506.0)及2种硫化物(MW 473.9和405.8).键级和键长分析也证实丁烯氟虫腈硫原子连接的化学键不稳定,易发生断裂重排反应,生成上述转化产物.%Photolysis of butylene fipronil was investigated, including reaction kinetics, transformation product identification and theoretical computation analysis. Photolysis of butylene fipronil under simulated sunlight was well fitted to first-order kinetic model with a half-life of 17.34min. Humic acids significantly reduced photoactivity of the insecticide, due to competitive light absorption, while NO3-and Cl-, didn't affect its photolysis. Major transformation products were identified as desulfinyl derivative (MW 442.0), sulfone derivative (MW 506.0) and sulfide derivatives (MW 473.9 and 405.8). The proposed pathway of the insecticide was further confirmed by bond order and bond length analysis. The bonds round sulfur atom were easily broken and rearranged to form the transformation products.