Rapf Rebecca J, Perkins Russell J, Dooley Michael R, Kroll Jay A, Carpenter Barry K, Vaida Veronica
Department of Chemistry and Biochemistry and Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado 80309, United States.
School of Chemistry and the Physical Organic Chemistry Centre, Cardiff University, Cardiff CF10 3AT, United Kingdom.
ACS Cent Sci. 2018 May 23;4(5):624-630. doi: 10.1021/acscentsci.8b00124. Epub 2018 Apr 18.
Sunlight can initiate photochemical reactions of organic molecules though direct photolysis, photosensitization, and indirect processes, often leading to complex radical chemistry that can increase molecular complexity in the environment. α-Keto acids act as photoinitiators for organic species that are not themselves photoactive. Here, we demonstrate this capability through the reaction of two α-keto acids, pyruvic acid and 2-oxooctanoic acid, with a series of fatty acids and fatty alcohols. We show for five different cases that a cross-product between the photoinitiated α-keto acid and non-photoactive species is formed during photolysis in aqueous solution. Fatty acids and alcohols are relatively unreactive species, which suggests that α-keto acids are able to act as radical initiators for many atmospherically relevant molecules found in the sea surface microlayer and on atmospheric aerosol particles.
阳光可通过直接光解、光敏化及间接过程引发有机分子的光化学反应，这通常会导致复杂的自由基化学过程，进而增加环境中的分子复杂性。α-酮酸可作为本身无光活性的有机物种的光引发剂。在此，我们通过丙酮酸和2-氧代辛酸这两种α-酮酸与一系列脂肪酸和脂肪醇的反应来证明这种能力。我们展示了在五种不同情况下，光引发的α-酮酸与非光活性物种之间的交叉产物在水溶液光解过程中形成。脂肪酸和醇是相对不活泼的物种，这表明α-酮酸能够作为在海面微层和大气气溶胶颗粒中发现的许多与大气相关分子的自由基引发剂。
