Ion–Molecule Reactions in Methyl Fluoride and Methyl Chloride

1971 ◽  
Vol 49 (13) ◽  
pp. 2217-2222 ◽  
Author(s):  
A. A. Herod ◽  
A. G. Harrison ◽  
N. A. McAskill
Keyword(s):  
Kinetic Energy ◽  
Methyl Chloride ◽  
Molecular Ions ◽  
Rate Coefficients ◽  
Minor Importance ◽  
Methyl Fluoride ◽  
Ion Molecule Reactions ◽  
Fragment Ions ◽  
Ion Energies ◽  
Ion Kinetic Energy

The reactions of the molecular ion have been studied as a function of the ion kinetic energy for methyl fluoride and methyl chloride. The following reactions are observed[Formula: see text]For methyl fluoride (X = F) reactions c and d have kinetic energy thresholds and become significant at high ion energies. For CH3Cl (X = Cl) reaction a is not observed and reactions c and d are of only minor importance at high ion energies. Rate coefficients for the molecular ions and a number of fragment ions as well as rate coefficients for further reaction of CH4X+ are reported.

Termolecular ion–molecule reactions involving C3H5+

1970 ◽  
Vol 48 (22) ◽  
pp. 3549-3553 ◽  
Author(s):  
A. G. Harrison ◽  
A. A. Herod
Keyword(s):  
Kinetic Energy ◽  
Molecular Size ◽  
Order Rate Constant ◽  
Second Order ◽  
Rate Coefficients ◽  
Third Order ◽  
Order Rate ◽  
Ion Molecule Reactions ◽  
Similar Dependence ◽  
Ion Kinetic Energy

The reaction of C3H5+ with C2D4 to produce C5H5D4+ is shown to be second order in C2D4. The rate coefficients are in the range 10−24 to 10−25 cm6 molecule−2 s−1 but decrease markedly with increasing ion kinetic energy. This decrease reflects the effect of the ion kinetic energy on the lifetime of the initial collision complex. Small differences in rate coefficients are observed depending on the source of the C3H5+ ion but these are insufficient to distinguish between possibly different ionic structures. The reaction of C3H5+ with C2H3F forms C5H7+ in a reaction second order in C2H3F. The rate coefficients are also in the range 10−24 to 10−25 cm6 molecule−1 s−1 and show a similar dependence on ion kinetic energy. These high third order rate constants are compared with data for other termolecular reactions and are shown to be consistent with the effect of molecular size on the third order rate constant.

Rearrangements in the Molecular Ions of Some ortho-Substituted Schiff Bases

1993 ◽  
Vol 46 (6) ◽  
pp. 895 ◽  
Author(s):  
T Blumenthal ◽  
M Dosen ◽  
RG Gillis ◽  
QN Porter
Keyword(s):  
Kinetic Energy ◽  
Schiff Bases ◽  
Molecular Ions ◽  
Energy Spectra ◽  
Supporting Evidence ◽  
Deuterium Labelling ◽  
Methyl Group ◽  
Molecular Ion ◽  
Fragment Ions ◽  
Ion Kinetic Energy

Under electron ionization conditions, the ortho-substituted Schiff bases N-benzylidene-o-toluidine (1a), N-(o-methylbenzylidene)aniline (1b), N-salicylideneaniline (1c) and N-(o-methoxybenzylidene)aniline (1d) give fragment ions which have been shown by collision-activated mass-analysed ion kinetic energy spectra to have the structure of the protonated molecular ions of indole (2), benzofuran (3), and 1,2-benzisoxazole (4). The molecular ion of N-(o-methylbenzylidene)-o-toluidine (1f) gives as fragment ions not only the protonated molecular ion (2) of indole and the tropylium ion but also the molecular ion of anthracene. Attempts to find supporting evidence for a mechanism for this rearrangement by deuterium labelling of a methyl group in (1b), such as (1g), have been unsuccessful.

Ion-molecule reactions in uranium hexafluoride

1975 ◽  
Vol 28 (9) ◽  
pp. 1879 ◽  
Author(s):  
NA McAskill
Keyword(s):  
Kinetic Energy ◽  
Gas Phase ◽  
Mass Spectrometer ◽  
Uranium Hexafluoride ◽  
Ion Source ◽  
Rate Coefficients ◽  
Medium Pressure ◽  
Ion Molecule Reactions ◽  
Ion Kinetic Energy

The ion-molecule reactions of UF6 in the gas phase were studied in a mass spectrometer fitted with a medium-pressure ion source. The main reactions were the collision-stabilized formation of U2F11+ from UF5+, U2F10+ from UF4+ and U3F16+ from U2F10+. Rate coefficients for the reactions of UF5+ and UF4+ with UF6 and the distribution of their products were found to depend upon the ion kinetic energy.

Negative Ionen durch Elektronenstoß aus organischen Nitroverbindungen, Äthylnitrit und Äthylnitrat

1967 ◽  
Vol 22 (5) ◽  
pp. 700-704
Author(s):  
K. Jäger ◽  
A. Henglein
Keyword(s):  
Electron Impact ◽  
Negative Ions ◽  
Molecular Ions ◽  
Ion Source ◽  
Negative Ion ◽  
Electron Affinities ◽  
Low Intensity ◽  
Ion Molecule Reactions ◽  
Fragment Ions ◽  
Product Ions

Negative ion formation by electron impact has been studied in nitromethane, nitroethane, nitrobenzene, tetranitromethane, ethylnitrite and ethylnitrate. Appearance potentials, ionization efficiency curves and kinetic energies of negative ions were measured by using a Fox ion source. The electron affinities of C2H5O and of C (NO2)3 are discussed as well as the energetics of processes which yield NO2-. The electron capture in nitrobenzene and tetranitromethane leads to molecular ions [C6H5NO2~ in high, C (NO2)4 in very low intensity] besides many fragment ions. A number of product ions from negative ion-molecule reactions has also been found.

Unimolecular Gas-Phase Reactions of Diethyl Phthalate, Isophthalate, and Terephthalate upon Electron Ionization

2003 ◽  
Vol 56 (5) ◽  
pp. 473 ◽  
Author(s):  
Susumu Tajima ◽  
Masashi Mamada ◽  
Satoshi Nakajima ◽  
Yutaka Takahashi ◽  
Nico M. M. Nibbering
Keyword(s):  
Gas Phase ◽  
Molecular Ions ◽  
Ion Source ◽  
Electron Ionization ◽  
Diethyl Phthalate ◽  
Gas Phase Reactions ◽  
Fragment Ions ◽  
Metastable Fragmentation ◽  
Primary Fragmentation ◽  
Ion Kinetic Energy

Unimolecular gas-phase reactions of diethyl phthalate (1), isophthalate (2), and terephthalate (3), upon electron ionization, have been investigated by use of mass-analyzed ion kinetic energy (MIKE) spectrometry and deuterium labelling. The metastable molecular ions (1)+ decompose to give exclusively the ions m/z 176 ([M – CH3CH2OH]+) and not the ions by the loss of CH3CH2O as proposed earlier in the literature. The metastable molecular ions (2)+ and (3)+ fragment differently from (1)+ and lead not only to the formation of the major fragment ions m/z 194 ([M − CH2CH2]+) via a McLafferty rearrangement but also to minor fragment ions m/z 193 ([M – CH2CH3]+).Yet, molecular ions decomposing in the ion source all show as primary fragmentation channel the loss of CH3CH2O to give the ions at m/z 177, which further dissociate to give the ions at m/z 149 through the loss of C2H4 or CO, indicating the resulting ions are +COC6H4COOH and +C6H4COOCH2CH3. The +COC6H4COOH ions decompose into the m/z 121, 93, and 65 ions by the consecutive losses of three carbon monoxide molecules, respectively. Prior to the second CO loss, a migration of the OH group to the benzene ring occurs. During the metastable fragmentation of the +C6H4COOCH2CH3 ions no ethoxy migration occurs, in contrast to the methoxy migration taking place in the metastable decomposition of the lower homologue +C6H4COOCH3 ions.

ION–MOLECULE REACTIONS IN METHYL ALCOHOL AND METHYL-d3 ALCOHOL

1966 ◽  
Vol 44 (14) ◽  
pp. 1655-1661 ◽  
Author(s):  
J. C. J. Thynne ◽  
F. K. Amenu-Kpodo ◽  
A. G. Harrison
Keyword(s):  
Methyl Alcohol ◽  
Rate Constants ◽  
Hydrogen Transfer ◽  
Rate Coefficients ◽  
Collision Complex ◽  
Ion Molecule Reactions ◽  
Ion Energies ◽  
Hydroxyl Hydrogen

The rate constants for the hydrogen-transfer ion-molecule reactions[Formula: see text]have been measured at thermal ion energies and found to be 12 × 10−10 cm3 molecule−1 s−1 and 8.0 × 10−10 cm3 molecule−1 s−1 respectively. The rate coefficients at higher ion energies (3.7 eV ion exit energy) show little change from these values. Reactions [a] and [b] have also been studied using CD3OH and it is found that in reaction [a] the hydroxyl hydrogen is transferred 2.5 times more readily at low ion energies and 1.8 times more readily at high ion energies than a methyl hydrogen. This rather small specificity would appear to preclude formation of a "locked-in" collision complex even at low ion energies.

Ion–molecule reactions in gaseous methyl amine

1967 ◽  
Vol 45 (24) ◽  
pp. 3119-3128 ◽  
Author(s):  
E. G. Jones ◽  
A. G. Harrison
Keyword(s):  
Rate Coefficients ◽  
Ion Energy ◽  
Methyl Amine ◽  
Ion Molecule Reactions ◽  
Ion Energies ◽  
Theoretical Predictions

The ion–molecule reactions in gaseous methyl amine have been studied. The following reactions have been identified and their rate coefficients (all in cm3 molecule−1 s−1 units) determined for ions of 3.4 eV ion exit energy. [Formula: see text]Reactions [a] and [c] were also studied at thermal ion energies and little variation of the rate coefficients with ion energy was found in contrast with theoretical predictions.

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