Department of Quantum Chemistry, Institute of Chemistry, Academy of Sciences of Moldova, Kishinev, Republic of Moldova.
J Environ Sci Health B. 2020;55(10):876-888. doi: 10.1080/03601234.2020.1790965. Epub 2020 Jul 12.
In the present work we have studied photo-induced decomposition of iprodione on silica support with different additions of titanium dioxide. Both the experimental and theoretical (DFT) approaches have been applied. It was found that 16 hours visible light exposure of the samples with 0.1% and 1.0% of TiO leads respectively to 48.28% and 21.05% of residual amounts of iprodione in these samples. A number of intermediates and end products were identified by means of GS-MS and LC-MS chromatography. The iprodione isomer (RP 30228) and its decay product 1-(3,5-dichlorophenyl)-5-isopropyl biuret (RP 36221) were identified among them. Our DFT calculations have revealed the detailed mechanisms of formation of the above products and the mechanism of accelerated proton-induced decomposition of iprodione molecules adsorbed on the TiO surface. Also, the intra-molecular reasons for iprodione stability in acidic media were clarified together with the mechanism of hydantoin cycle opening under the action of hydroxyl anions.
在本工作中，我们研究了在二氧化硅载体上不同添加量的二氧化钛的光诱导异丙菌酮分解。同时采用了实验和理论（DFT）方法。结果发现，在 0.1%和 1.0%TiO2 的样品中，分别进行 16 小时可见光照射，会导致这些样品中残留的异丙菌酮分别为 48.28%和 21.05%。通过 GS-MS 和 LC-MS 色谱鉴定出了一些中间体和终产物。其中包括异丙菌酮异构体（RP 30228）及其降解产物 1-(3,5-二氯苯基）-5-异丙基异氰脲酸酯（RP 36221）。我们的 DFT 计算揭示了上述产物形成的详细机制，以及吸附在 TiO 表面上的异丙菌酮分子在质子诱导下加速分解的机制。同时，还阐明了异丙菌酮在酸性介质中稳定的分子内原因，以及在氢氧根阴离子作用下尿嘧啶环打开的机制。
