Atmospheric Oxidation Mechanism of Furfural Initiated by Hydroxyl Radicals.
Atmospheric Oxidation Mechanism of Furfural Initiated by Hydroxyl Radicals.
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DOI：
10.1021/acs.jpca.7b00506
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发表时间：
2017-04
期刊：
影响因子：
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通讯作者：
Xiaocan Zhao;Liming Wang
中科院分区：
文献类型：
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作者：
Xiaocan Zhao;Liming Wang
糠醛被排放到大气中，因为其作为来自生物质、工业用途和生物质燃烧的烷烃燃料的中间体的潜在应用。糠醛化学的动力学和机理信息对于评估糠醛在大气中的归宿及其对空气质量的影响是必要的。本文采用量子化学和动力学计算方法研究了OH自由基引发糠醛大气氧化的机理。OH与糠醛的反应主要是通过OH加成到C2和C5位，形成R2和R5加合物而引发的，R2和R5加合物可分别快速开环形成R2 B和R5 B。我们的计算表明，这些中间自由基与O2在大气条件下反应相当缓慢，因为O2添加到这些自由基中仅轻微放热且高度可逆。或者，这些自由基将直接与O3、NO2、HO 2/RO 2等反应。也就是说，糠醛的大气氧化不太可能导致臭氧形成。在典型的大气条件下，OH引发的糠醛氧化的主要产物包括2-氧代-3-戊烯-1，5-二醛、5-羟基-2（5 H）-呋喃酮、4-氧代-2-丁烯酸和2，5-呋喃二酮。这些化合物可能会留在气相中，并受到进一步的光氧化。
Furfural is emitted into the atmosphere because of its potential applications as an intermediate to alkane fuels from biomass, industrial usages, and biomass burning. The kinetic and mechanistic information on the furfural chemistry is necessary to assess the fate of furfural in the atmosphere and its impact on the air quality. Here we studied the atmospheric oxidation mechanisms of furfural initiated by the OH radicals using quantum chemistry and kinetic calculations. The reaction of OH and furfural was initiated mainly by OH additions to C2 and C5 positions, forming R2 and R5 adducts, which could undergo rapid ring-breakage to form R2B and R5B, respectively. Our calculations showed that these intermediate radicals reacted rather slowly with O2 under the atmospheric conditions because the additions of O2 to these radicals are only slightly exothermic and highly reversible. Alternatively, these radicals would react directly with O3, NO2, HO2/RO2, etc. Namely, the atmospheric oxidation of furfural would unlikely result in ozone formation. Under typical atmospheric conditions, the main products in OH-initiated furfural oxidation include 2-oxo-3-pentene-1,5-dialdehyde, 5-hydroxy-2(5H)-furanone, 4-oxo-2- butenoic acid, and 2,5-furandione. These compounds will likely stay in the gas phase and are subject to further photo-oxidation.