【摘要】 根据分子轨道理论,借助半经验分子轨道计算方法研究吡虫啉可能的的光解途径,发现硝基亚氨基是接受光子能量后最不稳定的位置,并预测了各种可能的光解产物.以300 W中压汞灯(λ>280nm)为光源,实验发现吡虫啉在甲醇溶剂中的光解符合一级动力学规律,其主要降解产物为1-[(6-氯-3-吡啶)甲基]-2-咪唑酮.实验结果与理论预测结果吻合,从而提出了吡虫啉可能的光解途径.更多还原

【Abstract】 In this paper,we predicted the photolysis pathways of imidacloprid by semiempirical molecular orbital theoretical computations.Firstly,we obtained the main transition styles of imidacloprid at λ>280 nm by Configuration Interaction.Then we calculated the value of ΔM in these transition styles.The results showed that the bonds of N14-N15,C13=N14 and C8-N9 of imidacloprid tended to break.On the other hand,photodegradation behaviors of imidacloprid in methanol were studied under irradiation of a 300 W medium pressure mercury lamp(λ>280 nm).The primary degradation of imidacloprid followed a pseudo-first-order kinetics in methanol,and the photodegradation half life of imidacloprid in methol is about 67.9 min.The main photoproduct of imidacloprid was determined as 1-[(6-chloro-3-pyridinyl) methyl]-2-imidazolidone by GC/MS.The results of theoretical prediction agreed well with the experimental conclusions,which suggested that semiempirical molecular orbital theoretical computations could be potentially applied to predict the photolysis pathways of organic contaminations.更多还原