Kinetic and mechanistic studies of atmospheric degradation of diethyl pyrocarbonate initiated by OH radicals and chlorine atoms

The atmospheric reactivity of dicarbonyl compounds is becoming an increasing environmental concern due to the growth in their emissions, tracked by their usage as solvents and industrial additives during the last decades. In this paper, the gas phase degradation of diethyl pyrocarbonate (DEPC) initiated by both hydroxyl radicals and chlorine atoms was studied. The rate coefficients for the reaction between DEPC with OH radicals (k(OH)) and chlorine atoms (k(Cl)) were determined, being k(OH) = 1.2 x 10(-)(12) cm(3) molec(-1) s(-1) and k(Cl) = 3.4 x 10(-12) cm(3) molec(-1) s(-1). The analysis of the photo-oxidation products and the reaction mechanism were both experimentally determined by infrared spectroscopy and supported by theoretical calculations. Formations of dicarbonyl compounds (CH3CH2OC(O)OC(O)CH3, CH3CH2OC(O)OC(O)H), acetic acid, formic acid, formaldehyde, carbon monoxide, and carbon dioxide were observed. Finally, environmental implications are concluded based on the atmospheric lifetime of DEPC.

Automated summary

The study investigated the gas phase degradation of diethyl pyrocarbonate initiated by hydroxyl radicals and chlorine atoms, determining the rate coefficients for the reactions. Analysis of photo-oxidation products and reaction mechanism were conducted using infrared spectroscopy and theoretical calculations. The formation of dicarbonyl compounds and other products were observed, leading to conclusions on environmental implications based on the atmospheric lifetime of DEPC.