大气中相关的二级有机气溶成分的解离常数
Agata Kołodziejczyk1, Aleksandra Wróblewska1, Mariusz Pietrzak1
1Institute of Physical Chemistry, Polish Academy of Sciences, ul. Kasprzaka 44/52, 01-224, Warsaw, Poland.
Chemosphere
|January 15, 2024
概括
这项研究确定了来自烯的二次有机气溶成分的酸度常数 (pKa). 实验pKa值与其他方法有很好的相关性,但与in silico预测的相关性较低.
科学领域:
- 环境化学环境化学
- 大气化学 大气化学
- 有机化学 有机化学
背景情况:
- 二次有机气溶 (SOA) 显著影响空气质量和气候.
- 了解SOA组件的化学特性,如酸度,对于大气建模至关重要.
- 烯是生物性挥发性有机化合物和随后的SOA形成的丰富前体.
研究的目的:
- 合成和确定丰富的烯的关键碳酸氧化产物的酸度常数 (pKa).
- 将实验pKa值与计算方法预测的值进行比较.
- 根据文献数据验证实验方法.
主要方法:
- 合成精选的烯氧化产物 (碳素酸).
- 使用H NMR定位,pH-计量定位和贝茨-施瓦森巴赫光谱测量来确定pKa.
- 使用Marvin 21.17.0软件进行pKa值的计算,用于in silico比较.
主要成果:
- 测定化合物的实验pKa值在3.51 ± 0.01到5.18 ± 0.06之间.
- 1H NMR定位结果显示与电位计和紫外线光谱方法有很强的相关性 (R2 = 0.92).
- 使用马文软件的in silico预测显示出较低的相关性 (R2 = 0.66) 和系统地低估了实验值.
结论:
- 对基衍生SOA组件的pKa值的实验性确定是可靠的,并且在多种方法中一致.
- 像马文软件这样的计算方法需要进一步的细化,以准确地预测这些复杂的有机酸的pKa.
- 准确的pKa数据对于改善大气模型中SOA过程的表示至关重要.
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