A kinetic study of the reactions of OH radicals with fluoroethanes. Estimates of C—H bond strengths in fluoroalkanes

1983 ◽  
Vol 61 (5) ◽  
pp. 861-865 ◽  
Author(s):  
Jean-Pierre Martin ◽  
George Paraskevopoulos
Keyword(s):  
Kinetic Study ◽  
Gas Phase ◽  
Rate Constants ◽  
Flash Photolysis ◽  
Oh Radicals ◽  
Bond Dissociation Energies ◽  
Time Resolved ◽  
Dissociation Energies ◽  
Bond Strengths ◽  
Vacuum Uv

A kinetic study of the reactions of OH radicals with a series of fluoroethanes in the gas phase is presented. OH radicals were generated by flash photolysis of H2O vapor in the vacuum uv (λ > 165 nm) and were monitored in absorption by time-resolved attenuation of resonance radiation at 308.15 nm [OH(A2Σ+ → X2Π)]. The following absolute rate constants (in units of 109 cm3mol−1 s−1 at the 95% confidence limit) were determined at [Formula: see text][Formula: see text][Formula: see text][Formula: see text][Formula: see text]From a linear correlation of the present and previously published rate constants with bond dissociation energies, the following quantities (in kcal mol−1 at 298 K) were estimated to be: D(CH3CHF—H) = 96.3 ± 1.5, D(CH2FCHF—H = 98.8 ± 1.0, D(CF3CHF—H) = 103.5 ± 1.0, D(CHF2CF2—H) = 103.0 ± 1.5, and [Formula: see text][Formula: see text]

The bond dissociation energies of SO3—X– (X = F, Cl, Br, and I)

2005 ◽  
Vol 83 (11) ◽  
pp. 2013-2019 ◽  
Author(s):  
Changtong Hao ◽  
Thomas M Gilbert ◽  
Lee S Sunderlin
Keyword(s):  
Gas Phase ◽  
Lewis Acids ◽  
Basis Sets ◽  
Collision Induced Dissociation ◽  
Bond Dissociation Energies ◽  
Flowing Afterglow ◽  
Bond Dissociation ◽  
Dissociation Energies ◽  
Upper Limit ◽  
Bond Strengths

The gas-phase strengths of the SO3—X- bonds (X = Cl, Br, and I) have been determined to be 222 ± 13, 179 ± 11, and 161 ± 9 kJ/mol, respectively, by measuring thresholds for collision-induced dissociation in a flowing afterglow-tandem mass spectrometer. An upper limit of D(SO3—F–) ≤ 488 ± 19 kJ/mol was also determined. The periodic trends in the halide affinities of SO3 closely parallel those for SO2 and other Lewis acids. Bond strengths computed using the B3LYP, MP2, QCISD(T), and other models with several basis sets are generally lower than experiment.Key words: bond dissociation energies, computational chemistry, Lewis acids, superacids, halide affinities.

Rates of OH radical reactions. VII. Reactions of OH and OD radicals with n-C4H10, n-C4D10, H2 and D2, and of OH with neo-C5H12 at 297 K

1980 ◽  
Vol 58 (20) ◽  
pp. 2146-2149 ◽  
Author(s):  
George Paraskevopoulos ◽  
Wing S. Nip
Keyword(s):  
Gas Phase ◽  
Rate Constants ◽  
Room Temperature ◽  
Kinetic Isotope Effect ◽  
Flash Photolysis ◽  
Deuterium Atom ◽  
Oh Radicals ◽  
Confidence Limits ◽  
Kinetic Isotope ◽  
Absorption Technique

Absolute rate constants of hydrogen and deuterium atom abstraction by OH and OD radicals from n-C4H10, n-C4D10, H2 and D2, and by OH radicals from neo-C5H12 have been measured at room temperature in the gas phase using the flash photolysis-resonance absorption technique. The rate constants in units of cm3 mol−1 s−1 were found to be:[Formula: see text]The quoted errors are the 95% confidence limits. A kinetic isotope effect was observed when hydrogen was replaced by deuterium in the paraffin and H2, whereas there was no significant effect when OH was replaced by OD.

Rates of OH Radical Reactions. I. Reactions with H2, CH4, C2H6, and C3H8 at 295 K

1975 ◽  
Vol 53 (22) ◽  
pp. 3374-3382 ◽  
Author(s):  
R. P. Overend ◽  
G. Paraskevopoulos ◽  
R. J. Cvetanović
Keyword(s):  
Gas Phase ◽  
Rate Constants ◽  
Flash Photolysis ◽  
Hydrogen Abstraction ◽  
Resonance Absorption ◽  
Oh Radicals ◽  
Oh Radical ◽  
Absolute Rate ◽  
Absorption Spectrophotometry ◽  
Secondary Reactions

A fast flash photolysis kinetic spectrophotometer capable of measuring rates of up to 105 s−1 is described. The rates of hydrogen abstraction from H2, CH4, C2H6, and C3H8 by OH radicals at 295 ± 2 K, have been measured in the gas phase by hydroxyl resonance absorption spectrophotometry. The influence of secondary reactions on the measured rates and the derivation of the absolute rate constants is discussed in detail.The absolute rate constants in units of cm3 mol−1 s−1 were found to be: [Formula: see text][Formula: see text][Formula: see text] and [Formula: see text]

Rate constants for the gas–phase reactions of OH radicals with ethylene and halogenated ethylene compounds

1976 ◽  
Vol 65 (11) ◽  
pp. 4771-4777 ◽  
Author(s):  
Carleton J. Howard
Keyword(s):  
Gas Phase ◽  
Rate Constants ◽  
Oh Radicals ◽  
Gas Phase Reactions

Rate constants of the gas-phase reactions of OH radicals withtrans-2-hexenal,trans-2-octenal, andtrans-2-nonenal

2009 ◽  
Vol 41 (7) ◽  
pp. 483-489 ◽  
Author(s):  
Tingting Gao ◽  
Jean M. Andino ◽  
Carlos C. Rivera ◽  
Misaela Francisco Márquez
Keyword(s):  
Gas Phase ◽  
Rate Constants ◽  
Oh Radicals ◽  
Gas Phase Reactions

Rate constants for the gas-phase reaction of OH radicals with a series of ketones at 299 ± 2 K

1982 ◽  
Vol 14 (8) ◽  
pp. 839-847 ◽  
Author(s):  
Roger Atkinson ◽  
Sara M. Aschmann ◽  
William P. L. Carter ◽  
James N. Pitts
Keyword(s):  
Gas Phase ◽  
Rate Constants ◽  
Oh Radicals ◽  
Phase Reaction ◽  
Gas Phase Reaction
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