Rate Constants for the Gas Phase Reactions of Ozone with Diethylamine and Triethylamine

Abstract

Kinetics of the reactions of ozone with diethylamine (DEA) and triethylamine (TEA) were investigated in a self-made Teflon chamber.Experiments were conducted under pseudo-first-order decay conditions using excess DEA and TEA.Cyclohexane was added to the reactor to quench OH radicals.At (298±1) K and 1.01×105 Pa, the measured absolute rate constants were (1.33±0.15)×10-17 cm3·molecule-1·s-1 for DEA and (8.20±1.01)×10-17 cm3·molecule-1·s-1 for TEA.Comparing our results with data for the reactions of analogous amines with ozone, we propose that the amines react with ozone probably through an electrophilic reaction mechanism.In addition, the reactions of trialkylamines with ozone are all much faster than those of dialkylamines with ozone, which may explain the intriguing finding in several field studies where higher concentrations of dialkylammonium were detected in aerosol samples.The atmospheric lifetimes of DEA and TEA were also estimated based on the measured rate constants and the ambient tropospheric concentration of ozone, which indicates that the reaction with ozone is an important loss pathway for these amines in the atmosphere, especially in polluted areas.