Photodegradation mechanisms of 1-nitropyrene, an environmental pollutant: the effect of organic solvents, water, oxygen, phenols, and polycyclic aromatics on the destruction and product yields.
Photodegradation mechanisms of 1-nitropyrene, an environmental pollutant: the effect of organic solvents, water, oxygen, phenols, and polycyclic aromatics on the destruction and product yields.
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DOI：
10.1021/jp2126416
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发表时间：
2012-04-12
期刊：
影响因子：
--
通讯作者：
Arce R
中科院分区：
文献类型：
--
作者：
García-Berríos ZI;Arce R
这项工作描述了1-硝基芘（1-NO2Py）在由有机溶剂和气溶胶粒子的已知成分组成的化学模型系统中的光降解机制的研究。利用HPLC和HPLC- ms技术鉴定了1-羟基芘（1- ohpy）、1-羟基-x-硝基芘（1- oh -x- no2py）、1-亚硝基芘和1,6-和1,8-芘二酮等光产物，它们的量子产率与溶剂类型有显著的相关性。1-NO2Py的光降解量子产率φ(−1−NO2Py)在甲苯、苯和极性质子溶剂（10−3）中大于非极性和极性非质子溶剂（10−4）。在具有可提取氢原子的溶剂中，生成的产物产率较高的是1-OHPy和1-OH-x-NO2Py。这代表了60 - 80%的光破坏产率，是由氨基氧基自由基的提取和重组反应产生的，氨基氧基是一种中间产物，被认为是硝基芳烃中硝基-亚硝酸盐重排的结果。小O2对光降解产率的影响和azulene的猝灭实验表明，3（π,π*）态在1-NO2Py光反应中的贡献很小。在这些条件下没有观察到亚硝基甲苯的产物，证明了3（π,π*）态参与了它的形成。在各种酚类气溶胶成分存在的情况下，在所有溶剂中的光降解率提高了10倍。这种效应部分归因于3（π,π*）态与苯酚的反应。水的作用导致1-NO2Py的光降解率及其光产物的降低。研究了1-NO2Py在黏性溶剂十六烷中的光降解，并确定该介质不抑制其光降解。
This work describes studies of the photodegradation mechanism of 1-Nitropyrene (1-NO2Py) in a chemical model system consisting of an organic solvent and known constituents of an aerosol particle. Photoproducts such as 1-hydroxypyrene (1-OHPy), 1-hydroxy-x-nitropyrenes (1-OH-x-NO2Py), 1-nitrosopyrene and 1,6- and 1,8-pyrenediones were identified by HPLC and HPLC-MS techniques and their quantum yields show a significant dependence on the type of solvent. The photodegradation quantum yield of 1-NO2Py, ϕ(−1−NO2Py), was larger in toluene, benzene and polar protic solvents (10−3) in comparison with nonpolar and polar aprotic solvents, where the yield is in the order of 10−4. In solvents with an abstractable hydrogen atom the products formed in higher yields were 1-OHPy and 1-OH-x-NO2Py. These represent 60 to 80% of the photodestruction yield and result from abstraction and recombination reactions of the pyrenoxy radical, an intermediate postulated to be formed as a result of a nitro-nitrite rearrangement in nitroaromatics. The small O2 effect in the photodegradation yield and the quenching experiments with azulene demonstrate the small contribution of the 3(π,π*) state in the 1-NO2Py photoreaction. The nitrosopyrene product was not observed under these conditions, demonstrating the participation of the 3(π,π*) state in its formation. In the presence various phenols aerosol constituents the photodegradation yield increased by ten fold in all solvents. This effect is partly ascribed by the reaction of 3(π,π*) state with the phenol. The effect of water resulted in the reduction of the 1-NO2Py photodegradation yield and of its photoproducts. The phototodegradation of 1-NO2Py was also studied in a viscous solvent, hexadecane, and it was determined that this medium does not inhibit its photodecay.
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影响因子：
11.4
作者：
Feilberg, A;Nielsen, T
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影响因子：
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