Chattopadhyay Aparajeo, Chatterjee Piyali, Chakraborty Tapas
Department of Physical Chemistry, Indian Association for the Cultivation of Science, 2A Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India.
J Phys Chem A. 2015 Jul 23;119(29):8146-55. doi: 10.1021/acs.jpca.5b04905. Epub 2015 Jun 30.
Acetone photo-oxidation in synthetic air under exposure of 311 nm ultraviolet light has been studied, and the photo-oxidation products are identified by means of infrared spectroscopy. Analysis reveals that formic acid is one of the major products, although there have been debates in the past concerning the authenticity of formation of this acid in synthetic air via the photo-oxidation pathway. The quantum yield of formation of this acid is similar to that of other major photoproducts like methanol, formaldehyde, and carbon monoxide. The reaction yield, however, decreases with an increase in total air pressure in the reaction cell, but it is still significant at pressures relevant to tropospheric conditions. A kinetic model has been used to simulate the measured reaction kinetics, and the quantum yields predicted by the model are found to be consistent with the measured yields for different durations of light exposure. The same model has also been used to investigate the effect of atmospheric nitric oxide on the fate of formation of this acid in the troposphere. Although nitric oxide is known to be a quencher of peroxy radicals, the precursors of formaldehyde and formic acid in acetone photo-oxidation, but our model predicts that this oxide plays a positive role in the overall reaction kinetics for production of this acid in the troposphere.
研究了在311 nm紫外光照射下，丙酮在合成空气中的光氧化反应，并通过红外光谱对光氧化产物进行了鉴定。分析表明，甲酸是主要产物之一，尽管过去对于通过光氧化途径在合成空气中形成这种酸的真实性存在争议。这种酸的生成量子产率与甲醇、甲醛和一氧化碳等其他主要光产物的量子产率相似。然而，反应产率随着反应池中总气压的增加而降低，但在与对流层条件相关的气压下仍然显著。已使用动力学模型来模拟测量的反应动力学，并且发现该模型预测的量子产率与不同光照时间下的测量产率一致。同一模型还用于研究大气一氧化氮对对流层中这种酸生成命运的影响。尽管一氧化氮已知是过氧自由基的淬灭剂，而过氧自由基是丙酮光氧化中甲醛和甲酸的前体，但我们的模型预测，这种氧化物在对流层中该酸生成的整体反应动力学中起积极作用。
