Adam Mickiewicz University, Faculty of Chemistry, Department of Water Treatment Technology, ul. Drzymały 24, 60-613 Poznań, Poland.
J Hazard Mater. 2012 Aug 30;229-230:340-5. doi: 10.1016/j.jhazmat.2012.06.009. Epub 2012 Jun 21.
The paper concerns formation of N-nitrosodimethylamine (NDMA) upon ozonation of dimethylamine (DMA) aqueous solutions. According to current hypothesis ozonated DMA is oxidized to N-dimethylhydroxylamine (DMHA), then to N-methylhydroxylamine (MHA) and finally to hydroxylamine (HA). HA subsequently reacts with the remain part of DMA to form unsymmetrical dimethylhydrazine (UDMH). Finally UDMH undergoes oxidation with ozone to form NDMA. HA is thought to be an important by-product that increases the NDMA formation. We decided to verify the hypothesis by an ozonation of DMA aqueous solutions in the presence of DMHA, MHA and HA. We have clearly proved that ozonation of DMA in the presence of DMHA and/or MHA does not increase NDMA formation. These results do not exclude the possibility of HA formation during DMA ozonation, but unambiguously show that even if HA is formed during this reaction, it does not have any impact on NDMA formation. In authors opinion the formation of MHA and HA is however doubtful since both compounds seem to be rather products of reduction than oxidation. Therefore HA-DMA reaction cannot be responsible for the formation of NDMA when DMA aqueous solution is ozonized.
本文研究了臭氧氧化二甲胺（DMA）水溶液时生成 N-亚硝基二甲胺（NDMA）的情况。根据目前的假设，臭氧氧化 DMA 会先生成 N-二甲基羟胺（DMHA），然后是 N-甲基羟胺（MHA），最后是羟胺（HA）。HA 随后与 DMA 的剩余部分反应生成不对称二甲肼（UDMH）。最后，UDMH 与臭氧氧化生成 NDMA。HA 被认为是一种重要的副产物，会增加 NDMA 的生成。我们决定通过在 DMHA、MHA 和 HA 的存在下对 DMA 水溶液进行臭氧化来验证这一假设。我们已经清楚地证明，在 DMHA 和/或 MHA 存在的情况下对 DMA 进行臭氧化不会增加 NDMA 的形成。这些结果并不排除在 DMA 臭氧化过程中形成 HA 的可能性，但明确表明，即使在该反应中形成了 HA，它对 NDMA 的形成也没有任何影响。作者认为，MHA 和 HA 的形成是值得怀疑的，因为这两种化合物似乎更像是还原产物而不是氧化产物。因此，当臭氧氧化 DMA 水溶液时，HA-DMA 反应不能负责 NDMA 的形成。
