Hakala Jani P, Donahue Neil M
Center for Atmospheric Particle Studies , Carnegie Mellon University , 5000 Forbes Avenue , Pittsburgh , Pennsylvania 15213 , United States.
Institute for Atmospheric and Earth System Research, Department of Physics , University of Helsinki , P.O. Box 64, Helsinki , 00014 , Finland.
J Phys Chem A. 2018 Dec 13;122(49):9426-9434. doi: 10.1021/acs.jpca.8b09650. Epub 2018 Nov 30.
We explore the pressure dependence of a stabilized Criegee Intermediate (sCI) formation from a sequence of trans-alkene ozonolysis reactions. To study the effect of carbon chain length on the stabilization, we select five symmetric trans-alkenes ranging from trans-2-butene (C) through trans-7-tetradecene (C). We measure the pressure falloff curves for each alkene from 50 to 900 Torr in a flow reactor using conversion of SO to HSO with and without an OH scavenger, and subsequent detection of HSO with a nitrate chemical ionization mass spectrometer to constrain sCI yields. As the length of the carbon chain increases, we observe a systematic increase in Criegee Intermediate stabilization at a given pressure, along with a systematic decrease in the low-pressure limit. Our results also suggest that for these symmetrical systems the anticonformer of the Criegee Intermediate stabilizes before (at lower pressure than) the syn conformer.
我们通过一系列反式烯烃臭氧化反应来探究稳定态Criegee中间体（sCI）形成的压力依赖性。为了研究碳链长度对稳定性的影响，我们选择了五种对称反式烯烃，范围从反式-2-丁烯（C）到反式-7-十四碳烯（C）。我们在流动反应器中，使用有和没有OH清除剂时SO向HSO的转化率，并随后用硝酸化学电离质谱仪检测HSO来确定sCI产率，测量了每种烯烃在50至900托压力下的压力衰减曲线。随着碳链长度的增加，我们观察到在给定压力下Criegee中间体稳定性有系统性增加，同时低压极限有系统性降低。我们的结果还表明，对于这些对称体系，Criegee中间体的反式构象异构体比顺式构象异构体先稳定（在更低压力下）。
