THE ASSOCIATION REACTION C2H3++CO AND INTERSTELLAR PROPYNAL

Two different C3H3O+ ions were generated in a selected-ion flow tube o perating at room temperature. C-2 protonated propadienone, H2C=CHCO+, was produced by the association reaction between C2H3+ and CO. Protona ted propynal, HC=C-CHOH+, was produced by proton transfer to propynal, HC-C-CHO. The ions were identified by their proton transfer reactions with C2H5NH2, CH3NH2, C4H5N, NH3, (n-C4H9)(2)O, (C2H5)(2)CO, C6H10O, C6H6 and C2H5I. Rate coefficients and branching ratios are reported fo r these reactions. The implications of this work for the synthesis of HC=C-CHO in interstellar clouds are discussed.