Laboratory investigations of negative ion molecule reactions of propionic, butyric, glyoxylic, pyruvic and pinonic acids

Abstract We have carried out laboratory measurements of gas-phase ion-molecule-reactions of several negative ion species with propionic, butyric, glyoxylic, pyruvic, and pinonic acids. A flow reactor operating at a temperature of 293 ± 3 K and total gas pressures of 1.5 hPa, 9 hPa, or 40 hPa were used. The negative reagent ion species investigated included CO 3 − , CO 3 − H 2 O, NO 3 − , NO 3 − H 2 O, NO 2 − , NO 2 − H 2 O, and O 3 − . The reactions were found to proceed either via proton transfer, switching, or clustering. A new proton transfer channel leading to alkylperoxy carboxylate radicals (R −H (OO·)COO − ) was observed for propionic, butyric, and pinonic acids.