Product yields of stabilized Criegee intermediates in the ozonolysis reactions of cis-2-butene, 2-methyl-2-butene, cyclopentene, and cyclohexene

Abstract

Cavity ring-down spectroscopy (CRDS) was utilized in combination with chemical titration with sulfur dioxide (SO2) to quantify stabilized Criegee intermediates (sCIs) produced at low pressures (4–20 Torr) in ozonolysis reactions of cis-2-butene, 2-methyl-2-butene, cyclopentene, and cyclohexene. The yield of stabilized sCI, acetaldehyde oxide (CH3CHOO), from cis-2-butene ozonolysis decreased with decreasing pressure and reached to 0.05±0.04 at the zero-pressure limit. The nonsymmetric alkene 2- methyl-2-butene produced two stabilized sCIs, CH3CHOO and acetone oxide ((CH3)2COO), and their total yield decreased with decreasing pressure and reached 0.01±0.03 at the zero-pressure limit. For cyclopentene and cyclohexene, the sCI yields were essentially constant near zero, as expected of endocyclic alkenes. The nascent yields of sCI of various alkenes are compared.