A selected ion flow tube study of the reactions of various nitrogen containing ions with formic acid, acetic acid, and methyl formate

The possibility of forming organic molecules, such as the amino acid, glycine, from interstellar species through the ion-molecule reactions of ionized amine fragment compounds with neutral carboxylic acid and ester species has been investigated in a selected ion flow tube (SIFT) at 298 K. An earlier study showed that reactions of neutral amine species with ionized carboxylic acid or ester fragments does not result in the desired combination of groups but instead results in the fragmentation of the amines [D.M. Jackson, N.J. Stibrich, N.G. Adams, L.M. Babcock, Int. J. Mass Spectrom. 243 (2005) 115-120]. In the present study, the ion product distributions and reaction rate coefficients of the gas phase reactions of HCOOH, CH3COOH, and CH3OCHO with the ions Ar+, N2+, NH2+, NH3+, and HCNH+ have been determined. The ions Ar+ and N2+ fragment the neutral species in dissociative charge transfer, and the reactions of NH2+ and HCNH+ with the neutrals result in dissociative proton transfer. NH3+ reacts with all three species to form NH4+ by H atom abstraction. The reaction rate coefficients were on average within experimental error of the gas kinetic rate and were on the order of 10−9 cm3 s−1.