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.

Third-order rate constants of atmospheric importance

1983 ◽  
Vol 15 (11) ◽  
pp. 1189-1227 ◽  
Author(s):  
Roger Patrick ◽  
David M. Golden
Keyword(s):  
Rate Constants ◽  
Third Order ◽  
Order Rate

Kinetics and Rate Constants of Reactions Leading to Hydration of and in Gaseous Oxygen, Argon, and Helium Containing Traces of Water

1972 ◽  
Vol 50 (14) ◽  
pp. 2230-2235 ◽  
Author(s):  
J. D. Payzant ◽  
A. J. Cunningham ◽  
P. Kebarle
Keyword(s):  
High Pressure ◽  
Electron Beam ◽  
Gas Phase ◽  
Mass Spectrometer ◽  
Rate Constants ◽  
Gas Phase Reactions ◽  
Third Order ◽  
Gaseous Oxygen ◽  
Time Resolved ◽  
Pulsed Electron Beam

The rate constants for the forward and reverse components of gas phase reactions:[Formula: see text]were measured with a pulsed electron beam, time resolved detection high pressure mass spectrometer at 300 °K. O2, Ar, and He at pressures from 1–7 Torr were used as third gas M. The forward reactions were found to be third order and the reverse reactions second order. Establishment of the equilibria could also be observed.

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.

THE KINETICS OF THE DECOMPOSITION REACTIONS OF THE LOWER PARAFFINS: III. PROPANE

1938 ◽  
Vol 16b (11) ◽  
pp. 411-419 ◽  
Author(s):  
E. W. R. Steacie ◽  
I. E. Puddington
Keyword(s):  
Thermal Decomposition ◽  
High Pressure ◽  
Excellent Agreement ◽  
Rate Constants ◽  
Initial Pressure ◽  
First Order ◽  
Decomposition Reactions ◽  
Order Rate ◽  
Products Of Reaction ◽  
Kinetics Of

The kinetics of the thermal decomposition of propane has been investigated over a temperature range from 551° to 602 °C. The limiting high pressure first order rate constants are given by[Formula: see text]The first order rate constants fall off strongly with increasing percentage decomposition, and the rate decreases with decreasing pressure in a manner similar to the rate decrease in the decomposition of the butanes.Analyses of the products of reaction at various stages show them to be independent of temperature over the range examined, but to be affected by the initial pressure. This effect is undoubtedly due to the secondary hydrogenation of some of the initial products. The analytical results are in excellent agreement with those of Frey and Hepp.

CHARGE TRANSFER IN THE RADIOLYSIS OF BINARY HYDROCARBON MIXTURES

1966 ◽  
Vol 44 (10) ◽  
pp. 1175-1182 ◽  
Author(s):  
J. A. Stone ◽  
A. R. Quirt ◽  
O. A. Miller
Keyword(s):  
Charge Transfer ◽  
Ionization Potential ◽  
Ionization Potentials ◽  
Liquid Hydrocarbons ◽  
General Phenomenon ◽  
Saturated Hydrocarbons ◽  
Hydrocarbon Mixtures ◽  
Solvent Interaction ◽  
Lower Ionization Potential ◽  
Solute Solvent Interaction

The radiolysis of dilute solutions of ethane-dε, propane-d8, and n-butane-d10 in liquid hydrocarbons at 195 °K results in the production of D2 and HD in amounts which are determined by the relative ionization potentials of solvent and solute. Solvents of higher ionization potential enhance the production of D2 and HD from deuterated solutes of lower ionization potential. When the ionization potentials are in the reverse order the yields are diminished. This solute–solvent interaction, which is ionic in nature, is a general phenomenon in the radiolysis of mixtures of saturated hydrocarbons in the liquid phase and is consistent with charge transfer between solvent and solute.

Rate constants for the gaseous reactions OH + C2H4 and OH + OH

1980 ◽  
Vol 33 (7) ◽  
pp. 1425 ◽  
Author(s):  
GK Farquharson ◽  
RH Smith
Keyword(s):  
Mass Spectrometer ◽  
Hydroxyl Radicals ◽  
Rate Constant ◽  
Rate Constants ◽  
Order Rate Constant ◽  
Resonance Fluorescence ◽  
Flow Tube ◽  
Third Order ◽  
Order Rate ◽  
Wall Loss

The rate of disappearance of hydroxyl radicals (generated by H+NO2 → OH+NO) along a discharge flow tube both with and without ethene present was measured by resonance fluorescence. Stoichiometry was simultaneously measured with a mass spectrometer, the leak into which was located downstream of the resonance fluorescence cell. After allowing for loss of hydroxyl by known homogeneous reactions and for wall loss (when applicable) it was found that for OH+C2H4 the low pressure limiting third-order rate constant kter was (3.1 � 0.5)x 10-29 cm6 s-1 at approximately 298 K. In addition an estimate for the second- order rate constant for OH+OH was obtained, namely (1.7 � 0.2) × 10-12 cm3 s-1. These results are discussed in relation to previous measurements.

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