Dalton Evan Z, Hoffmann Erik H, Schaefer Thomas, Tilgner Andreas, Herrmann Hartmut, Raff Jonathan D
Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States.
Atmospheric Chemistry Department, Leibniz Institute for Tropospheric Research, 04318 Leipzig, Germany.
J Am Chem Soc. 2023 Jul 26;145(29):15652-15657. doi: 10.1021/jacs.3c03112. Epub 2023 Jul 18.
Halogen atoms are important atmospheric oxidants that have unidentified daytime sources from photochemical halide oxidation in sea salt aerosols. Here, we show that the photolysis of nitrate in aqueous chloride solutions generates nitryl chloride (ClNO) in addition to Cl and HOCl. Experimental and modeling evidence suggests that O(P) formed in the minor photolysis channel from nitrate oxidizes chloride to Cl and HOCl, which reacts with nitrite to form ClNO. This chemistry is different than currently accepted mechanisms involving chloride oxidation by OH and could shift our understanding of daytime halogen cycling in the lower atmosphere.
卤素原子是重要的大气氧化剂，其白天的来源不明，源于海盐气溶胶中光化学卤化物氧化。在此，我们表明，氯化物水溶液中硝酸盐的光解除了产生氯和次氯酸外，还生成硝酰氯（ClNO₂）。实验和模型证据表明，硝酸盐光解次要通道中形成的O(P)将氯化物氧化为氯和次氯酸，后者与亚硝酸盐反应生成ClNO₂。这种化学过程不同于目前公认的涉及OH氧化氯化物的机制，可能会改变我们对低层大气中白天卤素循环的理解。
