The Atmospheric Photo-Oxidation of Diethyl Carbonate: Kinetics, Products, and Reaction Mechanism

RIMONDINO, GUIDO N; PELAEZ, WALTER J; MALANCA, FABIO E

JOURNAL OF PHYSICAL CHEMISTRY A

AMER CHEMICAL SOC

Año: 2019

1089-5639

he rate coefficient for the gas-phase of diethyl carbonate with chlorine atoms has been determined at 298 K using a relative method, employing ethyl formate and ethyl acetate as reference compounds. The experimental value, (1.0 ± 0.2) × 10−11 cm3 molecule-1 s-1, is in good correlation with the one estimated by the SAR (Structure-Activity Relationship) method.The photo-oxidation mechanism of diethyl carbonate initiated by chlorine atoms was also studied at 298 K and atmospheric pressure as a function of the oxygen partial pressure. The main products identified by infrared spectroscopy were: CH3CH2OC(O)OCHO, CH3CH2OC(O)OCH2CHO, CH3CH2OC(O)OC(O)CH3, CO2, CO, HCOOH, and CH3COOH. The results reveal that the oxidation process occurs by the abstraction of a hydrogen atom from the methyl (43%) and methylene (57%) groups. The relative importance of each reaction path from the primary radicals formed in photo-oxidation and the identity of CH3CH2OC(O)OCHO, CH3CH2OC(O)OC(O)CH3, and CH3CH2OC