Ion–molecule reactions in carbonyl sulfide – hydrocarbon mixtures

1970 ◽  
Vol 48 (4) ◽  
pp. 664-673 ◽  
Author(s):  
I. Džidić ◽  
A. Good ◽  
P. Kebarle
Keyword(s):  
Mass Spectrometer ◽  
Cross Sections ◽  
Rate Constants ◽  
Carbonyl Sulfide ◽  
Independent Set ◽  
Graphical Analysis ◽  
Ion Molecule Reactions ◽  
Product Ions ◽  
The Individual ◽  
Approximate Rate

The major ion–molecule reactions occurring in pure COS and in mixtures of COS with methane, methyl iodide, ethane, and ethylene were investigated in a Nier-type mass spectrometer. In cases where two or more reactions could be postulated to account for the observed product ions, appearance potential data and graphical analysis were used to evaluate the contributions of the individual reactions. Phenomenological cross sections were obtained for the reactions studied and approximate rate constants were then calculated.An independent set of measurements were carried out in a high-pressure pulsed-beam mass spectrometer, in which the absolute rate constants for reactions occurring in COS were measured, using nitrogen as a carrier gas. The rate constants thus obtained were used to verify the validity of the rate constants calculated from the measured cross sections.

Ion–molecule reactions in the binary mixture of acetaldehyde and trioxane. II. Mechanism for the reaction of acetaldehyde molecular ion with trioxane

1978 ◽  
Vol 56 (4) ◽  
pp. 533-537 ◽  
Author(s):  
Minoru Kumakura ◽  
Kazuo Arakawa ◽  
Toshio Sugiura
Keyword(s):  
Binary Mixture ◽  
Mass Spectrometer ◽  
Rate Constants ◽  
Positive Charge ◽  
Time Of Flight ◽  
Intermediate Complex ◽  
Hydrogen Atoms ◽  
Flight Mass Spectrometer ◽  
Ion Molecule Reactions ◽  
Product Ions

The ionic reaction of CH3CHO+with trioxane in acetaldehyde–trioxane mixtures has been studied using a time-of-flight mass spectrometer. The product ions, C3H5O2+, C3H6O2+, and C3H7O2+, were formed by condensation–elimination reactions, which involve the elimination of aformaldehyde molecule. The dissociation of the intermediate-complex, CH3CHO(CH2O)3+*, leads to the formation of the product ions. The structure of the complex is linear with localized positive charge. Rearrangement of hydrogen atoms occurs in the complex but not extensive scrambling. From the distribution of the isotopic product ions in acetaldehyde-d4–trioxane mixtures it was proposed that the origins of the product ions are the acetaldehyde molecule (reactant ion) and fragments from trioxane. The rate constants for the product ions formed in acetaldehyde (or acetaldehyde-d4)–trioxane mixtures were obtained.

Thermal Ion-Molecule Reactions in Oxygen-Containing Molecules. Condensation-Elimination Reactions in Dimethyl Ether-Trioxane Mixtures

1977 ◽  
Vol 32 (12) ◽  
pp. 1533-1540 ◽  
Author(s):  
Minoru Kumakura ◽  
Toshio Sugiura
Keyword(s):  
Isotope Effect ◽  
Dimethyl Ether ◽  
Mass Spectrometer ◽  
Rate Constants ◽  
Linear Structure ◽  
Ionization Efficiency ◽  
Ion Molecule Reactions ◽  
Fragment Ions ◽  
Product Ions ◽  
Elimination Reactions

Abstract Thermal ion-molecule reactions in dimethyl ether - trioxane mixtures have been studied with a time-of-flight mass spectrometer. The appearance potentials and ionization efficiency curves of product and major fragment ions were measured by an RPD technique. The product ions, having a linear structure such as CH3OCH3(CH2O)n+, CH3OCH3(CH2O)nH+, CH3OCH2(CH2O)n+, and CH3OCH2(CH2O)nH+ (n = 1 - 3), are formed by condensation-elimination reactions of CH3OCH3+ and CH3OCH2+ with trioxane. The formation of the product ions involves the dissociation of an intermediate-complex, which has a linear structure. It was found that homo-elimination of neutral products occurs preferentially from the trioxane molecule site in the complex. Extensive scrambling does not take place. The rate constants for the ions formed in dimethyl ether (or dimethyl-d6 ether) - trioxane mixtures are obtained, and a small isotope effect is observed. The rate constants of the condensation-elimination reactions of CH3OCH2+ with trioxane are compared with those with dimethyl ether.

COLLISIONS OF LONG-LIVED EXCITED IONS OF OXYGEN AND NITROGEN

1964 ◽  
Vol 42 (11) ◽  
pp. 2086-2101 ◽  
Author(s):  
William McGowan ◽  
Larkin Kerwin
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Ion Beam ◽  
Collision Induced Dissociation ◽  
Ion Molecule Reactions ◽  
Collision Region ◽  
Mean Lifetime ◽  
New States ◽  
Product Ions

The role of some excited ions in laboratory ion–molecule reactions has been investigated, and their possible importance in the upper atmosphere considered. The mass spectrometer techniques of Aston banding and of comparing I.P. curves of parent and product ions have been applied to studies of collision-induced dissociation and charge exchange of oxygen and nitrogen in their parent gas. In every case studied, cross sections depended markedly upon the presence in the ion beam of ions in metastable or long-lived radiative states. In order that an ion reach the collision region, it had to have a mean lifetime greater than 3 μsec.The a 4Πu and b 4Σg excited states of O2+ were identified in the collision[Formula: see text]Higher states of O2+, which have not as yet been identified spectroscopically, were found in the collision[Formula: see text]The thresholds of these new states are 23.9, 27.9, 31.3, and 34.1 eV with an uncertainty ±0.2 eV. From the collision-induced dissociation of N2+, the A 2Πu and the [Formula: see text] states have been identified. Also, the reported transfer of the ν = 3 level of the B [Formula: see text] to the ν = 14 level of the A 2Πu was found.The cross section for 10/01 charged exchange of N2+ in N2 exhibited a marked decrease as excited-state ions diluted the beam. The 10/01 collisions of N+ in N2 and O+ in O2 exhibited an increase in cross section as metastables were added to the parent ion beam. The 10/20 reaction of O2+ in O2 was also observed to depend on excited O2+ ions.

Ion-molecule reactions in ketones

1965 ◽  
Vol 18 (8) ◽  
pp. 1153 ◽  
Author(s):  
Souza BC de ◽  
JH Green
Keyword(s):  
Cross Sections ◽  
Hydrogen Abstraction ◽  
Reaction Cross ◽  
Ion Source ◽  
Principal Mode ◽  
Ion Molecule Reactions ◽  
Elevated Pressures ◽  
Secondary Ions ◽  
Ion Proton ◽  
Approximate Rate

Reactions with gaseous ketones in the ion source of a mass spectrometer at elevated pressures have been studied. Reaction cross sections and approximate rate constants are reported for reactions leading to ions of mass M + 1, where M is the mass of the parent ion. Proton transfer rather than hydrogen abstraction seems to be the principal mode of reaction in the formation of these secondary ions.

Mass Spectra and Ion Chemistry of Methylphosphine, Dimethylphosphine and Dimethyldeuterophosphine, Investigated by Ion Cyclotron Resonance Spectrometry

1975 ◽  
Vol 30 (3) ◽  
pp. 329-339 ◽  
Author(s):  
Karl-Peter Wanczek
Keyword(s):  
Rate Constants ◽  
Cyclotron Resonance ◽  
Mass Spectra ◽  
Ion Cyclotron Resonance ◽  
Exchange Reactions ◽  
Ion Chemistry ◽  
Ion Molecule Reactions ◽  
Ion Cyclotron ◽  
Product Ions ◽  
Ion Cyclotron Resonance Spectrometry

The mass spectra and the ion molecule reactions of methylphosphine, dimethylphosphine and dimethyldeuterophosphine have been studied by ion cyclotron resonance spectrometry. About 50 ion molecule reaction are observed for each compound. The product ions can be classified as ions with two phosphorus atoms: P2R5+, P2R3+, P2R2+ and P2R+ (R = CH3 or H), as phosphonium and phosphinium ions and ions resulting from collision dissociations and charge exchange reactions. Tertiary ions with three phosphorus atoms like CH3P3H2+ (from CH3PH2) and (CH3)4P3H2 (from (CH3)2PH) have also been detected. The mechanisms of the ion molecule reactions, rearrangements, P -H- and C-H-reactivities and product ion structures are discussed, using in the case of dimethylphosphine the results obtained with the deuterated compound. Rate constants of formation of the more abundant product ions from the molecular ion and the CH3P+ ion, both odd electron particles, have been determined. The reactions with dimethylphosphine have much smaller rate constants than the reactions with methylphosphine.

CONCURRENT ION–MOLECULE REACTIONS IN ETHYLENE AND PROPYLENE

1963 ◽  
Vol 41 (2) ◽  
pp. 236-242 ◽  
Author(s):  
A. G. Harrison
Keyword(s):  
Field Strength ◽  
Mass Spectrometer ◽  
Cross Sections ◽  
High Pressures ◽  
Ion Source ◽  
Molecule Reaction ◽  
Ion Molecule Reactions ◽  
Secondary Ions ◽  
The Cross

The ion–molecule reactions occurring in ethylene and in propylene at high pressures in the mass spectrometer ion source have been studied. It has been shown that two of the six secondary ions in ethylene and four of the nine secondary ions studied in propylene are products of more than one ion–molecule reaction. The cross sections for the separate reactions at 10 v/cm field strength are reported.

Ion-molecule reactions of methyl fluoride and methylene chloride

1970 ◽  
Vol 23 (11) ◽  
pp. 2301 ◽  
Author(s):  
NA McAskill
Keyword(s):  
High Pressure ◽  
Gas Phase ◽  
Mass Spectrometer ◽  
Cross Sections ◽  
Main Product ◽  
Methylene Chloride ◽  
Reaction Cross ◽  
Rate Coefficients ◽  
Ion Molecule Reactions ◽  
Reaction Cross Sections

The ion-molecule reactions of CH3F and CH2Cl2 were examined in the gas phase using a high-pressure mass spectrometer. The ionic products of CH3F were mainly CH2F+, C2H6F+, and CH4F+. In the CH2Cl2 system the main product was CHCl2+ together with smaller amounts of CH2Cl+, CH3Cl2+, and several condensation ions. The ionic reactivity of the two compounds was compared to that of other halomethanes. Rate coefficients and reaction cross sections for many primary reactant ions were measured as a function of the ion exit energy.

Concurrent ion–molecule reactions. III. Reactions in mixtures of HCl and HCN with D2 and CD4

1967 ◽  
Vol 45 (12) ◽  
pp. 1321-1327 ◽  
Author(s):  
A. G. Harrison ◽  
J. C. J. Thynne
Keyword(s):  
Field Strength ◽  
Cross Sections ◽  
Rate Constants ◽  
The Self ◽  
Ion Molecule Reactions ◽  
Ion Energies

The concurrent ion–molecule reactions in mixtures of HCl and HCN with D2 and CD4 have been studied by the ratio plot method. The following reactions have been detected in mixtures with HCN and their cross sections determined at 10.5 V cm−1 repeller field strength. [Formula: see text]In mixtures of D2 and CD4 with HCl the following reactions have been detected and cross sections determined. [Formula: see text]Rate constants for the self-reactions in HCN and HCl have been measured both at 10.5 V cm1 repeller field and at thermal ion energies.

Ion–molecule reactions in vinyl fluoride

1969 ◽  
Vol 47 (6) ◽  
pp. 957-964 ◽  
Author(s):  
J. A. Herman ◽  
A. G. Harrison
Keyword(s):  
Charge Transfer ◽  
Rate Constants ◽  
Order Reaction ◽  
Third Order ◽  
Vinyl Fluoride ◽  
Ion Molecule Reactions ◽  
Fragment Ions ◽  
Consecutive Reactions ◽  
Product Distributions ◽  
The Individual

The ion–molecule reactions in vinyl fluoride have been studied as a function of pressure and electron energy. The C2H2+ and C2HF+ fragment ions react predominantly by charge transfer while C2H3+ produces C2H4F+ and C4H5+. The C2H2F+ fragment forms C2H4F+, CHF2+, C2H3F2+, C4H4F+, and probably C2H3+. The rate constants for the individual reactions have been measured. The C2H3F+ ion reacts to form C3H5+, C3H4F+, C3H3F2+, and C4H5F+ (in minor yield), both by a second order and by a third order reaction. The rate constants and product distributions from the individual reactions have been evaluated. A number of consecutive reactions have been identified and shown to be third order processes.

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