Pressure Stabilization of Criegee Intermediates Formed from Symmetric trans-Alkene Ozonolysis,The Journal of Physical Chemistry A

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Pressure Stabilization of Criegee Intermediates Formed from Symmetric trans-Alkene Ozonolysis
The Journal of Physical Chemistry A ( IF 2.7 ) Pub Date : 2018-11-16 00:00:00 , DOI: 10.1021/acs.jpca.8b09650
Jani P. Hakala _{1,

2} , Neil M. Donahue _{1,

2}

Affiliation

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 (C₄) through trans-7-tetradecene (C₁₄). We measure the pressure falloff curves for each alkene from 50 to 900 Torr in a flow reactor using conversion of SO₂ to H₂SO₄ with and without an OH scavenger, and subsequent detection of H₂SO₄ 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.

中文翻译：

由对称反式烯烃臭氧分解形成的中间体中间体的压力稳定

我们探讨了从一系列反烯烃臭氧分解反应中稳定的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，我们选择了五个对称的反式烯烃，范围从反式2-丁烯（C ₄）到反式7-十四碳烯（C ₁₄）。我们在使用和不使用OH清除剂的情况下，将SO ₂转化为H ₂ SO ₄，并随后检测H ₂ SO ₄，在流动反应器中测量了50至900 Torr每种烯烃的压力下降曲线。用硝酸盐化学电离质谱仪限制sCI收率。随着碳链长度的增加，我们观察到在给定压力下，Criegee中级稳定系统地增加，同时低压极限也有系统地降低。我们的结果还表明，对于这些对称系统，Criegee Intermediate的反构象异构体在合成构象异构体之前（在比同构构象异构体低的压力下）稳定下来。

更新日期：2018-11-16

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