Temperature-Dependent Kinetics of the Reactions of the Criegee Intermediate CHOO with Aliphatic Aldehydes.

Criegee intermediates, formed by alkene ozonolysis in the troposphere, can react with volatile organic compounds (VOCs). The temperature-dependent kinetics of the reactions between the Criegee intermediate CHOO and three aliphatic aldehydes, RCHO where R = H, CH, and CH (formaldehyde, acetaldehyde, and propionaldehyde, respectively), have been studied using a laser flash-photolysis transient absorption spectroscopy technique. The experimental measurements are supported by calculations at various composite levels of theory that characterize stationary points on the reaction potential and free energy surfaces.

Temperature-Dependent Kinetics of the Reactions of the Criegee Intermediate CHOO with Hydroxyketones.

Though there is a growing body of literature on the kinetics of CIs with simple carbonyls, CI reactions with functionalized carbonyls such as hydroxyketones remain unexplored. In this work, the temperature-dependent kinetics of the reactions of CHOO with two hydroxyketones, hydroxyacetone (AcOH) and 4-hydroxy-2-butanone (4H2B), have been studied using a laser flash photolysis transient absorption spectroscopy technique and complementary quantum chemistry calculations. Bimolecular rate constants were determined from CHOO loss rates observed under pseudo-first-order conditions across the temperature range 275-335 K.