Details

Autor(en) / Beteiligte

• Zou, Meijun
• Liu, Tianlin
• Vansco, Michael F.
• Sojdak, Christopher A.
• Markus, Charles R.
• Almeida, Raybel
• Au, Kendrew
• Sheps, Leonid
• Osborn, David L.
• Winiberg, Frank A. F.
• Percival, Carl J.
• Taatjes, Craig A.
• Klippenstein, Stephen J.
• Lester, Marsha I.
• Caravan, Rebecca L.

Titel

Bimolecular Reaction of Methyl-Ethyl-Substituted Criegee Intermediate with SO2

Ist Teil von

• The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory, 2023-11, Vol.127 (43), p.8994-9002

Ort / Verlag

United States: American Chemical Society

Erscheinungsjahr

2023

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Methyl-ethyl-substituted Criegee intermediate (MECI) is a four-carbon carbonyl oxide that is formed in the ozonolysis of some asymmetric alkenes. MECI is structurally similar to the isoprene-derived methyl vinyl ketone oxide (MVK-oxide) but lacks resonance stabilization, making it a promising candidate to help us unravel the effects of size, structure, and resonance stabilization that influence the reactivity of atmospherically important, highly functionalized Criegee intermediates. We present experimental and theoretical results from the first bimolecular study of MECI in its reaction with SO2, a reaction that shows significant sensitivity to the Criegee intermediate structure. Using multiplexed photoionization mass spectrometry, we obtain a rate coefficient of (1.3 ± 0.3) × 10–10 cm3 s–1 (95% confidence limits, 298 K, 10 Torr) and demonstrate the formation of SO3 under our experimental conditions. Through high-level theory, we explore the effect of Criegee intermediate structure on the minimum energy pathways for their reactions with SO2 and obtain modified Arrhenius fits to our predictions for the reaction of both syn and anti conformers of MECI with SO2 (k syn = 4.42 × 1011 T–7.80exp­(−1401/T) cm3 s–1 and k anti = 1.26 × 1011 T–7.55exp­(−1397/T) cm3 s–1). Our experimental and theoretical rate coefficients (which are in reasonable agreement at 298 K) show that the reaction of MECI with SO2 is significantly faster than MVK-oxide + SO2, demonstrating the substantial effect of resonance stabilization on Criegee intermediate reactivity.