Selected ion flow tube studies of the reactions of H3O+, NO+, and O2+ with some chloroalkanes and chloroalkenes

We describe the results of a selected ion flow tube study of the reactions of H3O+, NO+, and O-2(+) with the chloromethanes CH3Cl, CH2Cl2, CHCl3, and CCl4, the chloroethanes CH2ClCH2Cl, CH3CHCl2, CH3CCl3, and CHCl2CHCl2, and the chloroethylenes CHClCCl2 and C2Cl4. The H3O+ reactions with these molecules, M, are mostly rapid but unusually varied, the most evident processes being direct proton transfer producing MH+ ions, ion/molecule association producing H3O+. M ions, HCl elimination from the protonated molecule producing (M-Cl)(+) ions, and even incorporation of H2O into the ion with the elimination of one or two HCl molecules. The NO+ reactions are generally slow and proceed largely via ion/molecule association producing NO+.M ions. Only one of the reactions, that of CH3CCl3, is fast and proceeds via Cl- transfer producing CH3CCl2+: and an NOCl molecule. The O-2(+) reactions are apparently all fast and proceed via charge transfer producing the parent cations M+ and via dissociative charge transfer with the elimination of Cl atoms and HCl molecules. In only one of these O-2(+) reactions (that with CHCl2CHCl2) is the carbon-carbon bond broken. (C) 1999 Elsevier Science B.V.