State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Science, Beijing 100012, China.
J Phys Chem A. 2012 Feb 23;116(7):1710-6. doi: 10.1021/jp2100864. Epub 2012 Feb 8.
The reaction of isoprene and methacrolein with ozone was investigated at different stages in the condensed phase at temperatures from 15 to 265 K by IR spectroscopy. The results revealed the following overall reaction process: the generation of primary ozonide (POZ), then its decomposition, and finally conversion into secondary ozonide (SOZ), which supported the Criegee mechanism. In the POZ and SOZ of isoprene, ozone cyclo-added preferentially to the double-bond that is not substituted by the methyl group. For methacrolein, the mainly detected SOZ is claimed to be MACSII formed by recombination of the intermediate CH(2)OO radical with aldehyde carbonyl of methylglyoxal in stead of the ketone carbonyl group. Theoretical calculations were performed at the B3LYP//MP2/6-311++G (2d, 2p) level to analyze the resulting spectrum. The good agreement between the calculated infrared spectra of POZ and SOZ and the experimental spectra supports the above-described findings.
采用红外光谱法在 15 至 265 K 的温度下，研究了异戊二烯和甲基丙烯醛在凝聚相的不同阶段与臭氧的反应。结果表明，该反应的总过程为：生成初级臭氧化物（POZ），然后分解，最后转化为次级臭氧化物（SOZ），这支持了 Criegee 机理。在异戊二烯的 POZ 和 SOZ 中，臭氧优先环加成到未被甲基取代的双键上。对于甲基丙烯醛，主要检测到的 SOZ 被认为是 MACSII，它是由 CH(2)OO 自由基与甲基乙二醛的醛羰基的重组形成的，而不是酮羰基。通过 B3LYP//MP2/6-311++G（2d，2p）水平进行了理论计算，以分析得到的光谱。POZ 和 SOZ 的计算红外光谱与实验光谱之间的良好一致性支持了上述发现。
