Oxidation of ethanol vapors in negative atmospheric corona discharge

Ethanol vapors were oxidized in negative atmospheric corona discharge of double wires-to-planes geometry using three diameters of coronating wires and three power levels. Acetaldehyde, formaldehyde, CH₃COOH, and CO were detected as intermediate gaseous products of oxidation, and CO₂ was the final product. Comparison was made with the results of the previous work on oxidation of acetone. The lowest energy cost for oxidation was at the thickest electrode ø 0.8 mm, lowest discharge power 15 W, and equaled 1.1 kWh/g for acetone and 0.33 kWh/g for ethanol. In contrast to acetone, the ethanol molecule is oxidized directly by ozone with the rate constant 2.9 × 10^-20 cm³/s. Concentrations of intermediate products acetaldehyde and formaldehyde remain at the same levels at all power levels and wire diameters used. Scheme of chemical transformation is proposed for acetone and ethanol vapor oxidation, which suggests that reactions are initiated by interaction with atomic oxygen, ozone, and hydroxyl radicals.