The Impact of pH and NaCl and CaCl2 Salts on the Speciation and Photochemistry of Pyruvic Acid in the Aqueous Phase.
The Impact of pH and NaCl and CaCl2 Salts on the Speciation and Photochemistry of Pyruvic Acid in the Aqueous Phase.
复制标题
pH 值以及 NaCl 和 CaCl2 盐对水相中丙酮酸的形态和光化学的影响。
DOI：
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发表时间：
2020
影响因子：
2.9
通讯作者：
V. Grassian
中科院分区：
文献类型：
--
作者：
Man Luo;D. Shemesh;M. N. Sullivan;M. R. Alves;Meishi Song;R. Gerber;V. Grassian
最近的研究表明，在水相中照射后，藜芦酸可以产生更高分子量的化合物。这些化合物可有助于形成二次有机气溶胶。有几个以前的研究，离子强度的影响，光化学中的藻酸，然而，他们很少调查的影响，海洋相关的盐，如NaCl和CaCl 2。研究了NaCl和CaCl_2，即含有配位阳离子Na ~+和Ca ~（2+）的NaCl和CaCl_2，在不同pH值的水溶液中，对藜芦酸的形态、吸附性质和光反应性的影响。NMR结果表明，Ca ~（2+）和Na ~+都使藜芦酸进一步去质子化，使藜芦酸的二醇酮比比在相同pH值的纯水中降低，特别是在更酸性的pH（pH小于4）下。在NaCl/CaCl_2溶液中，葡糖酸的n → π ~* 跃迁的吸收峰发生了明显的红移。与单价阳离子（Na+）相比，这种依赖性对于二价阳离子（Ca 2+）更加显著。垂直激发能计算表明，在Ca ~（2+）存在下，丙酮酸的n → π ~* 跃迁峰也发生了同样的红移。此外，NaCl/CaCl 2的存在下抑制的光分解速率的甜菜酸，这可能是由于去质子化的甜菜酸的阳离子和较低的光化学反应性的丙酮酸，去质子化的形式。
Recent studies have shown that pyruvic acid can produce higher-molecular-weight compounds upon irradiation in the aqueous phase. These compounds can contribute to the formation of secondary organic aerosols. There have been several previous studies on the effect of ionic strength on the photochemistry of pyruvic acid, however; few of them investigated the effects of marine relevant salts such as NaCl and CaCl2. In this study, we examine the effect of NaCl and CaCl2, namely the containing coordinating cations Na+ and Ca2+, on the speciation, absorption properties and photoreactivity of pyruvic acid in aqueous solutions of varying pH. NMR shows that both Ca2+ and Na+ further deprotonate pyruvic acid and decrease the diol to ketone ratio of pyruvic acid than in pure water at the same pH, especially at more acidic pH (pH less than 4). The absorption spectrum shows a strong red shift in the peak maxima for the n → π* transition of pyruvic acid in NaCl/CaCl2 solutions. This dependence is much more pronounced for divalent cations (Ca2+) compared to monovalent cations (Na+). Vertical excitation energy calculations of the anionic ketone form of pyruvic acid confirm the same red shift on the n → π* transition peak in the presence of Ca2+. In addition, the presence of NaCl/CaCl2 suppress the photolysis rate of pyruvic acid, which could be due to the deprotonation of pyruvic acid by the cations and the lower photochemical reactivity for pyruvate, the deprotonated form.
影响因子：
15
作者：
Rapf RJ;Perkins RJ;Yang H;Miyake GM;Carpenter BK;Vaida V
通讯作者：
Vaida V
影响因子：
3.4
作者：
Ezell, Michael J.;Wang, Weihong;Finlayson-Pitts, Barbara J.
通讯作者：
Finlayson-Pitts, Barbara J.
影响因子：
4.6
作者：
Eugene, Alexis J.;Guzman, Marcelo I.
通讯作者：
Guzman, Marcelo I.