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.

Ion–molecule reactions in vinyl chloride and vinyl bromide

1969 ◽  
Vol 47 (4) ◽  
pp. 647-653 ◽  
Author(s):  
J. A. Herman ◽  
J. J. Myher ◽  
A. G. Harrison
Keyword(s):  
Vinyl Chloride ◽  
Rate Coefficient ◽  
Order Reaction ◽  
Second Order ◽  
Third Order ◽  
Vinyl Bromide ◽  
Ion Molecule Reactions ◽  
Fragment Ions ◽  
Product Distributions ◽  
Energy Formula

The following ion–molecule reactions involving fragment ions in vinyl chloride have been studied and rate constants measured for ions of 2.4 eV exit energy.[Formula: see text]The reaction of the C2H3Cl+ molecule-ion produces C3H4Cl+, C4H5Cl+, and C4H6Cl+ both in a second order and a third order reaction. The apparent rate coefficient for the second order reaction is approximately 1 × 10−11 cm3 molecule−1 s−1 while that for the third order reaction is approximately 1 × 10−25 cm6 molecule−2 s−1. The product distributions from both the second and third order reactions have been determined.In vinyl bromide the C2H3+ ion produces C4H5+, C4H6+, and C2H4Br+ while the C2H3Br+ ion reacts to form C4H6Br+ both in a second order and a third order reaction.

Kinetics of the reaction between hexamethylenediisocyanate and 1-pentanol

1983 ◽  
Vol 48 (11) ◽  
pp. 3279-3286
Author(s):  
Slavko Hudeček ◽  
Miloslav Bohdanecký ◽  
Ivana Hudečková ◽  
Pavel Špaček ◽  
Pavel Čefelín
Keyword(s):  
Liquid Chromatography ◽  
Rate Constants ◽  
Reversed Phase ◽  
Order Reaction ◽  
Second Order ◽  
Second Order Reaction ◽  
Reversed Phase Liquid Chromatography ◽  
Consecutive Reactions ◽  
Phase Liquid ◽  
Kinetics Of

The reaction between hexamethylenediisocyanate and 1-pentanol in toluene was studied by means of reversed-phase liquid chromatography. By employing this method, it was possible to determine all components of the reaction mixture including both products, i.e. N-(6-isocyanate hexyl)pentylcarbamate and N,N'-bis(pentyloxycarbonyl)hexamethylenediamine. Relations for the calculation of kinetic constants were derived assuming a competitive consecutive second-order reaction. It was demonstrated that the reaction involved in this case is indeed a second-order reaction, and the rate constants of the first and second consecutive reactions were determined.

Partial methylation of methyl α-D- and β-D-threofuranoside

1990 ◽  
Vol 55 (7) ◽  
pp. 1777-1782 ◽  
Author(s):  
Jiří Jarý ◽  
Miroslav Marek ◽  
Ivan Raich
Keyword(s):  
Sodium Hydroxide ◽  
Methyl Iodide ◽  
Rate Constants ◽  
Relative Rate ◽  
Hydroxyl Groups ◽  
Partial Methylation ◽  
Methylation Rate ◽  
Consecutive Reactions ◽  
Relative Rate Constants ◽  
The Individual

The methylation rate of hydroxyl groups of the title glycosides I and II has been studied in their reaction with methyl iodide and sodium hydroxide in acetonitrile. From the relative rate constants determined for the side and consecutive reactions taking place the differences in methylation rate of the individual hydroxyl groups have been deduced and are discussed from the standpoint of possible steric and polar effects.

Kinetics of Methylation of Methyl 5-Deoxy-α/β-D-xylofuranosides

2004 ◽  
Vol 69 (10) ◽  
pp. 1877-1888
Author(s):  
Mária Oščendová ◽  
Jitka Moravcová
Keyword(s):  
Sodium Hydroxide ◽  
Methyl Iodide ◽  
Rate Constants ◽  
Reaction Rate ◽  
Steric Effect ◽  
Order Reaction ◽  
Half Time ◽  
First Order ◽  
Consecutive Reactions ◽  
Kinetics Of

The kinetics of methylation of methyl 5-deoxy-α-D-xylofuranoside (1), methyl 5-deoxy-β-D-xylofuranoside (2) and their partly methylated derivatives with methyl iodide in the presence of sodium hydroxide in acetonitrile was studied. The reaction rate was independent of the base concentration during the first half-time only and the methylation proceeded as a first-order reaction. The rate constants of all side and consecutive reactions were calculated and the influence of both polar and steric effect is discussed. The methylation of 1 was highly regioselective giving almost exclusively 5-deoxy-2-O-methyl-α-D-xylofuranoside.

Negative ion – molecule reactions

1969 ◽  
Vol 47 (10) ◽  
pp. 1815-1820 ◽  
Author(s):  
E. E. Ferguson
Keyword(s):  
Charge Transfer ◽  
Rate Constants ◽  
Reaction Rate ◽  
Reaction Rate Constant ◽  
Negative Ion ◽  
Transfer Reactions ◽  
Ion Molecule Reactions ◽  
Charge Transfer Reactions ◽  
Three Body ◽  
Interchange Reactions

Laboratory reaction rate constant measurements for negative ion – atom interchange reactions, negative ion charge transfer reactions, and negative ion three-body association reactions of aeronomic interest are reviewed and the available data tabulated. The present experimental techniques in use are briefly summarized. Most of the rate constants have been measured only at 300 °K; in a few cases data is available at energies [Formula: see text] as well as at 300 °K, so that an indication of the energy dependence of the rate constants is available.

Flow-tube studies of reactions of selected ions with cyanoacetylene

1985 ◽  
Vol 63 (4) ◽  
pp. 854-861 ◽  
Author(s):  
A. B. Raksit ◽  
D. K. Bohme
Keyword(s):  
Charge Transfer ◽  
Active Role ◽  
Flow Tube ◽  
Interstellar Gas ◽  
Ion Flow ◽  
Ion Molecule Reactions ◽  
Product Distributions ◽  
Selected Ion Flow Tube ◽  
Molecular Synthesis

Rate constants and product distributions have been determined for ion/molecule reactions of cyanoacetylene (HC3N) with He+, C+(2P), CH3+, C2+, C2H+, C2H2+, CN+, C2N+, C2N2+, N2+, CO+, H3+, N2H+, HCO+, C2H3+, H3O+, CH3NO2H+, CH3CNH+, (CH3)2COH+, i-C3H7OH2, C3H+, and C4N+. The measurements were performed with the selected-ion flow-tube (SIFT) technique at 296 ± 2 K. The observed reactions exhibit a variety of pathways including charge transfer, proton transfer, condensation, and association. The condensation and association reactions are suited for molecular growth by ion/molecule reactions. Special consideration is given to the active role of cyanoacetylene in the possible molecular synthesis which occurs in dense interstellar gas clouds by ion/molecule reactions.

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.

The formation and reactions of aromatic dimer cations in a high pressure photoionization source

1980 ◽  
Vol 58 (16) ◽  
pp. 1666-1672 ◽  
Author(s):  
John A. Stone ◽  
Margaret S. Lin
Keyword(s):  
High Pressure ◽  
Charge Transfer ◽  
Ionization Potential ◽  
Rate Constants ◽  
Aromatic Compounds ◽  
Third Order ◽  
Order Rate ◽  
Lower Ionization Potential ◽  
The Difference

Aromatic dimer cations (M2+) have been generated for a series of aromatic compounds in a high pressure photoionization source. Relative third order rate constants for formation of M2+ have been obtained for benzene (1.0), benzene-d6 (2.7), toluene (0.8), o-xylene (1.5), p-xylene (0.7), fluorobenzene (0.3), m-fluorotoluene (0.5), m-chlorotoluene (0.7), p-chlorotoluene (0.5), and o-methoxytoluene (0.4). These values are consistent with and supplement previous data for such systems. Reagent ion monitoring has been used to determine the relative rates of reaction of both M2+ and the monomer ions, M+, with a series of (mainly) aromatic compounds (X). Reaction of C6H6+ is by charge transfer to compounds of lower ionization potential than C6H6. (C6H6)2+ reacts only by charge transfer, if the ionization potential of X is more than 0.5 eV lower than that of benzene. When the difference is smaller, mixed dimer cations are observed which are probably formed in a switching reaction (C6H6)2+ + X → (C6H6•X)+ + C6H6.

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