Rate of recombination of ethyl radicals in the gas phase

1972 ◽  
pp. 764 ◽  
Author(s):  
R. M. Marshall ◽  
J. H. Purnell
Keyword(s):  
Gas Phase ◽  
Ethyl Radicals

The mercury (63P1) photosensitized hydrogenation of ethylene. Kinetics of the reaction C2H5 + H2 = C2H6 + H

1968 ◽  
Vol 46 (20) ◽  
pp. 3275-3281 ◽  
Author(s):  
L. E. Reid ◽  
D. J. Le Roy
Keyword(s):  
Gas Phase ◽  
Molecular Hydrogen ◽  
Mercury Vapor ◽  
Experimental Conditions ◽  
Working Pressure ◽  
Extinction Coefficients ◽  
Secondary Reactions ◽  
Ethyl Radicals ◽  
Kinetics Of ◽  
Hydrogenation Of Ethylene

A quantitative study has been made of the reaction of ethyl radicals with molecular hydrogen in the gas phase in the temperature range 240 to 320 °C. The mercury (63Pi) photosensitized decomposition of hydrogen in the presence of ethylene was used to generate ethyl radicals. Extinction coefficients for the absorption of 2537 Å by mercury vapor were measured and Beer's law was shown to be obeyed under the experimental conditions used. The corrections required to allow for the nonuniformity of radical concentrations in the cell were small. After delineating the experimental conditions necessary to minimize secondary reactions, the rate constant (cm3 mole−1 s−1) for the reaction C2H5 + H2 = C2H6 + H was found to be given by log10k = 12.57 − 13.7/θ. Experiments in the presence of added carbon dioxide showed the absence of hot radical effects at the working pressure of 92 Torr of hydrogen.

Spin relaxation of muonium‐substituted ethyl radicals (MuCH2ĊH2) in the gas phase

1996 ◽  
Vol 105 (17) ◽  
pp. 7517-7535 ◽  
Author(s):  
Donald G. Fleming ◽  
James J. Pan ◽  
Masayoshi Senba ◽  
Donald J. Arseneau ◽  
Robert F. Kiefl ◽  
...  
Keyword(s):  
Gas Phase ◽  
Spin Relaxation ◽  
Ethyl Radicals

Temperature Dependence of Disproportionation–Combination Ratios for Alkyl Radicals in Liquid Methane

1971 ◽  
Vol 49 (17) ◽  
pp. 2861-2867 ◽  
Author(s):  
Hugh A. Gillis
Keyword(s):  
Activation Energy ◽  
Temperature Dependence ◽  
Gas Phase ◽  
Rate Constants ◽  
Room Temperature ◽  
Transition States ◽  
Alkyl Radicals ◽  
Liquid Methane ◽  
Ethyl Radicals

The ratios of rate constants for disproportionation to combination have been measured for ethyl radicals and for i-propyl radicals in liquid methane between −181 and −94 °C. The radicals were generated by γ-radiolysis of dilute methane solutions of ethylene-d4 or propylene-d6. The activation energy for combination was found to exceed that for disproportionation by 290 ± 30 cal mol−1 for ethyl radicals and by 255 ± 25 cal mol−1 for i-propyl radicals. In both cases the disproportionation—combination ratio in the liquid, extrapolated to room temperature, is greater than that in the gas phase by a factor of about 2.5. These results are interpreted as indicating that disproportionation and combination reactions proceed by way of different transition states.

Reactions of thiyl radicals. XII. Triplet mercury photosensitized decomposition of ethyl sulfide in the gas phase

1976 ◽  
Vol 54 (8) ◽  
pp. 1290-1295 ◽  
Author(s):  
Conrad S. Smith ◽  
Arthur R. Knight
Keyword(s):  
Quantum Yield ◽  
Gas Phase ◽  
Quantum Yields ◽  
Second Step ◽  
Primary Process ◽  
Reaction Products ◽  
Process Comparison ◽  
Thiyl Radicals ◽  
Ethyl Radicals ◽  
High Sulfide

The triplet mercury photosensitized decomposition of ethyl sulfide vapour has been studied at 25 °C. The reaction products include C2H4 (Φ0 = 0.075), C2H6 (Φ0 = 0.043), C4H10 (Φ0 = 0.011), C2H5SH (Φ0 = 0.068), 4-methyl-3-thiahexane (Φ0 = 0.011), and C2H5SSC2H5 (Φ0 = 0.175). The overall decomposition quantum yield is 0.38 at high sulfide pressures. The initial decomposition gives principally ethyl radicals and ethylthiyl radicals; a second step which yields ethylene and ethanethiol may account for up to 20% of the primary process. Comparison of the direct and sensitized decompositions indicates that both likely originate in the triplet manifold of ethyl sulfide.Primary decomposition quantum yields have been accurately redetermined for the direct, 254 nm, photolysis of methyl sulfide (0.51), methylethyl sulfide (0.46), and ethyl sulfide (0.49).

Effect of Water Vapor on the Combination and Disproportionation of Ethyl Radicals in the Gas Phase

2004 ◽  
Vol 108 (10) ◽  
pp. 1638-1639 ◽  
Author(s):  
Pui-Teng Howe ◽  
Askar Fahr ◽  
Allan H. Laufer
Keyword(s):  
Water Vapor ◽  
Gas Phase ◽  
Effect Of Water ◽  
Ethyl Radicals

The Temperature Dependence of the Ratio kd/kc for Ethyl Radicals

1975 ◽  
Vol 53 (8) ◽  
pp. 1237-1244 ◽  
Author(s):  
D. G. Hooper ◽  
M. Simon ◽  
M. H. Back
Keyword(s):  
Liquid Phase ◽  
Transition State ◽  
Gas Phase ◽  
Rate Constants ◽  
Low Temperatures ◽  
Experimental Error ◽  
Hydrogen Atoms ◽  
Direct Photolysis ◽  
Temperature Range ◽  
Ethyl Radicals

The ratio of the rate constants for disproportionation and combination for ethyl radicals, kd/kc[Formula: see text]has been measured over the temperature range 298–173 K in the gas phase. Ethyl radicals were produced by direct photolysis of ethylene followed by addition of hydrogen atoms to ethylene. At low temperatures the only important reactions of the radicals were combination and disproportionation. The ratio kd/kc was obtained from measurements of the rates of formation of ethane, butane, and butene. No change in the ratio kd/kc was observed over the temperature range studied, leading to the conclusion that Ed − Ec = 0, within the experimental error. The significance of this result is discussed in relation to other measurements in both gas and liquid phase and to the nature of the transition state for this reaction.

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