Formation of nitroanthracene and anthraquinone from the heterogeneous reaction between NO2 and anthracene adsorbed on NaCl particles.
Formation of nitroanthracene and anthraquinone from the heterogeneous reaction between NO2 and anthracene adsorbed on NaCl particles.
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DOI：
10.1021/es501543g
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发表时间：
2014-07
影响因子：
11.4
通讯作者：
Wenyuan Chen;T. Zhu
中科院分区：
文献类型：
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作者：
Wenyuan Chen;T. Zhu
多环芳烃（PAHs）的氧化性衍生物，即硝基多环芳烃和醌类化合物，属于半挥发性有害有机化合物，但其在大气颗粒物上的非均相反应生成机理尚不清楚。在298 K暗条件下，研究了不同相对湿度（RH 0-60%）下，蒽与NO2在NaCl颗粒表面的非均相反应.主要产物9，10-蒽醌（9，10-AQ）和9-硝基蒽（9-NANT）的形成被确定为相对于NO2浓度的二级反应。在低相对湿度（0-20%）条件下，9，10-AQ的生成速率随相对湿度的增加而增加，而在高相对湿度（40-60%）条件下，随着相对湿度的进一步增加，9，10-AQ的生成速率下降。相反，在整个RH范围（0-60%）内，9-NANT的形成速率随着RH的增加而显著降低。两种不同的反应途径分别讨论了9，10-AQ和9-NANT的形成，两者都被认为是耦合到NO2与NaCl底物的主要反应。这些结果表明，相对湿度，控制NaCl颗粒表面吸附水的量，起着重要的作用，在NO2与吸附的多环芳烃的非均相反应。
Oxidative derivatives of polycyclic aromatic hydrocarbons (PAHs), that is, nitro-PAHs and quinones, are classed as hazardous semivolatile organic compounds but their formation mechanism from the heterogeneous reactions of PAHs adsorbed on atmospheric particles is not well understood. The heterogeneous reaction of NO2 with anthracene adsorbed on NaCl particles under different relative humidity (RH 0-60%) was investigated under dark conditions at 298 K. The formation of the major products, 9,10-anthraquinone (9,10-AQ) and 9-nitroanthracene (9-NANT), were determined to be second-order reactions with respect to NO2 concentration. The rate of formation of 9,10-AQ under low RH (0-20%) increased as the RH increased but decreased when the RH was further increased in high RH (40-60%). In contrast, the rate of formation of 9-NANT across the whole RH range (0-60%) decreased significantly with increasing RH. Two different reaction pathways are discussed for the formation of 9,10-AQ and 9-NANT, respectively, and both are considered to be coupled to the predominant reaction of NO2 with the NaCl substrate. These results suggest that relative humidity, which controls the amount of surface adsorbed water on NaCl particles, plays an important role in the heterogeneous reaction of NO2 with adsorbed PAHs.