Atmospheric oxidation of ethyl methyl carbonate: Kinetics and reaction mechanism

Ethyl methyl carbonate (EMC, CH3CH2OC(O)OCH3) is used industrially as an electrolyte for lithium-ion batteries and its production and use is expected to increase in the coming years, with a consequent increase in its atmospheric emissions. In this work, the photo-oxidation of EMC initiated by chlorine atoms in the gas phase was studied. The rate coefficient of the reaction between EMC and chlorine atom was determined by the relative method giving a mean value of (6.1 +/- 0.5) x 10-12 cm3 molec-1 s  1. The products resulting from atmospheric photo-oxidation of EMC at 298 K and 760 torr total pressure were identified and quantified by infrared spectroscopy: CH3C(O)OC(O)OCH3 (35 %), CH3OC(O)OC(O)H (14 %), CH3OH (30 %), HC(O)OH (12 %), HC(O)H (6 %), CO2 (84 %), and CO (28 %). Theoretical calculations were performed using the Gaussian09 program to obtain the infrared spectra of the products not available in the literature. Finally, from the kinetic analysis and the observed products, an atmospheric reaction mechanism is here proposed.