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Chlorine/UV treatment of anatoxin-a by activation of the secondary amine functional group
Environmental Science: Water Research & Technology ( IF 3.5 ) Pub Date : 2020-03-17 , DOI: 10.1039/c9ew01112a
Moshan Chen 1, 2, 3, 4 , Ernest R. Blatchley 1, 2, 3, 4, 5
Affiliation  

Studies of the combined application of chlorine and UVC radiation (Cl/UV) have generally focused on target compound degradation by the combined effects of direct photolysis and reactions with radical intermediates. However, prechlorination also has the potential to impart structural changes on molecules that increase their sensitivity to direct photolysis. Specifically, the prechlorination of amines leads to formation of their N-chlorinated derivatives, which is important because the N–Cl bond is photolabile. The Cl/UV process was examined for degradation of the secondary amines anatoxin-a (ANTX-a) and dimethylamine. ANTX-a and dimethylamine were both shown to undergo rapid N-chlorination. The first-order rate constant for photodecomposition of N-chlorodimethylamine at 254 nm was estimated to be 1.13 ± 0.05 × 10−3 cm2 mJ−1, while dimethylamine does not absorb UV254 radiation. The photodegradation of Cl-ANTX-a was also observed to be faster than direct photolysis of ANTX-a. For comparison, a first-order rate constant for photodegradation of Cl-ANTX-a of 1.86 ± 0.05 × 10−3 cm2 mJ−1 at 254 nm was estimated for N-chlorinated anatoxin-a, as compared 1.19 ± 0.02 × 10−3 cm2 mJ−1 for anatoxin-a. The observed increase in first-order rate of photodegradation illustrated activation of anatoxin-a toward photolysis by prechlorination.

中文翻译:

活化仲胺官能团的氯/紫外线处理抗毒素a

氯和UVC辐射(Cl / UV)联合应用的研究通常集中于目标化合物的降解,包括直接光解和与自由基中间体反应的联合作用。但是,预氯化还可能赋予分子以结构改变的作用,从而增加其对直接光解的敏感性。特别是,胺的预氯化作用会导致其N-氯化衍生物的形成,这很重要,因为N-Cl键具有光不稳定性。检查了Cl / UV工艺中仲胺类抗毒素a-毒素(ANTX-a)和二甲胺的降解情况。ANTX-a和二甲胺都显示出快速的N-氯化反应。N光分解的一阶速率常数在254nm处的-氯二甲基胺估计为1.13±0.05×10 -3 cm 2 mJ -1,而二甲基胺不吸收UV 254辐射。还观察到Cl-ANTX-a的光降解比ANTX-a的直接光解更快。为了进行比较,对于CL-ANTX-A的1.86±0.05×10光降解的一级速率常数-3厘米2毫焦耳-1在254nm估计为Ñ -chlorinated类毒素-A,与1.19±0.02×10 −3 cm 2兆焦−1用于抗毒素-a。观察到的一级光降解速率的增加说明了抗毒素a通过预氯化作用向光解的活化。
更新日期:2020-03-17
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