David Osborne - The effect of N-heteroatoms and CH3 substituents on dissociative electron–ion recombination of protonated single six membered ring compounds at room temperature

Version 1

      Publication Details (including relevant citation   information):

      International Journal of Mass   Spectrometry

        Volume 308, Issue 1, 1 November 2011, Pages 114-117


      Electron–ion dissociative recombination rate constants have been   determined for protonated single six-membered hydrocarbon rings   with varying N-atom substitution in the rings and varying degrees   of methyl substitutions to the rings. The species studied have   been protonated forms of the xylenes   (C8H10; with configurations o, m, and p),   the picolines (C6H7N; with methyl   substitutions located at 2, 3, and 4), mesitylene   (C9H12) and 2, 5-lutidine   (C7H9N). By operating at high reactant   vapor pressures, ternary association has been made to dominate   over recombination to create proton bound dimers and the rate   constants of these species have been determined. The studies were   made at room temperature in a flowing afterglow with a Langmuir   probe to determine the reduction in electron density as a   function of distance along the flow tube. All of the data except   for mesitylene showed a consistent trend with the numbers of   N-atom substitutions and CH3 attached to the rings.   For the protonated species, the rate constants increase with the   number of nitrogens and decreased with number of CH3  substituents attached to the ring. For proton bound dimers, the   rate constants increase with both, the number of N-atoms and   number of CH3 substituents. For the xylene and   picoline isomer's the measurements showed that the rate constants   were independent of isomeric form, and thus, it is not necessary   to study all isomeric forms. The relevance of these studies to   the ionosphere of Titan is discussed.

      Address (URL): http://www.sciencedirect.com/science/article/pii/S1387380611003125