50457-58-4Relevant articles and documents
Dissociative proton transfer reactions of H3+, N2H+, and H3O+ with acyclic, cyclic, and aromatic hydrocarbons and nitrogen compounds, and astrochemical implications
Milligan, Daniel B.,Wilson, Paul F.,Freeman, Colin G.,Meot-Ner (Mautner), Michael,McEwan, Murray J.
, p. 9745 - 9755 (2007/10/03)
A flowing afterglow-selected ion flow drift tube has been used to measure the rate coefficients and product ion distributions for reactions of H3O+, N2H+, and H3+ with a series of 16 alkanes, alkenes, alkynes, and aromatic hydrocarbons as well as acrylonitrile, pyrrole, and pyridine. Exothermic proton transfer generally occurs close to the collision rate. The reactions of H3O+ are mostly nondissociative and those of H3+ are mostly dissociative, but many reactions, especially those of N2H+, have both dissociative and nondissociative channels. The dissociative channels result mostly in H2 and/or CH4 loss in the small hydrocarbons and in toluene, loss of C2H2 from acrylonitrile, and loss of HCN from pyrrole. Only nondissociative proton transfer is observed with benzene, pyridine, and larger aromatics. Drift tube studies of N2H+ reactions with propene and propyne showed that increased energy in the reactant ion enhances fragmentation. Some D3+ reactions were also investigated and the results suggest that reactions of H3+ with unsaturated hydrocarbons B proceed through proton transfer that forms excited (BH+)* intermediates. Pressure effects suggest that a fraction of the (BH+)* intermediates decomposes too rapidly to allow collisional stabilization in the flow tube (t -8 s). The other low-energy (BH+)* intermediates are formed by the removal of up to 40% of the reaction exothermicity as translational energy, and these intermediates result in stable BH+ products. The results suggest that, in hydrogen-dominated planetary and interstellar environments, the reactions of H3+ can convert C2-C6 hydrocarbons to smaller and less saturated molecules, but polycyclic aromatics are stable against decomposition by this mechanism. The dissociative reactions of H3+ can therefore favor the accumulation of small unsaturated hydrocarbons and aromatics in astrochemical environments.
Gas-phase measurements of the kinetics of BF2(+)-induced polymerization of olefinic monomers
Forte, Leonard,Lien, Min H.,Hopkinson, Alan C.,Bohme, Diethard K.
, p. 1576 - 1583 (2007/10/02)
The initial steps in the BF2(+)-induced polymerization of the monomers of ethylene, propylene, cis-2-butene, isobutene, and styrene have been observed in the gas phase at room temperature using the Selected-Ion Flow Tube (SIFT) technique.Rate constants and product distributions have been determined for the initiation of the polymerization in each case.All five initiation reactions were found to be rapid (k >/= 5.0*10-10 cm3 molecule-1 s-1).The primary product ions that propagate polymerization have been identified and sequential addition reactions have been followed in all five systems.For ethylene the energetics of the initial steps have been followed using ab initio molecular orbital theory.Reaction of BF2+ with the vapours of water and benzene have also been characterized. Key words: ion-induced polymerization; alkenes; kinetics; gas phase ion chemistry
The Study of Ion-Molecule Reactions in the Gas Phase using a Triple Quadrupole Mass Spectrometer. Part 1. The Reactions of CH3+, CD3+, and C2H5+ with Simple Olefins
Batey, Jonathan H.,Tedder, John M.
, p. 1263 - 1268 (2007/10/02)
A triple quadrupole mass spectrometer has been used to study the reactions of simple carbocations with low molecular weight olefins in the gas phase at relatively high pressures (1E-3-1E-4 Torr).In each case a high energy 'addition complex' is formed which fragments spontaneously to give daughter ions, the extent of fragmentation depending to some extent on the pressure and on the translational energy of the primary ions.Also formed are 'second generation' ions due to reactions of the predominant daughter ions with the olefin.Ions with the same mass as the high energy 'addition complexes' have been fragmented by collision (C.I.D.) with inert molecules (N2) to yield similar daughter ions to those found from the 'addition complexes'.In the reactions, involving CD3+ ions, deuterium is widely, but not completely randomly, distributed among the daughter ions.
