Reactions of trifluoromethyl and methyl radicals with ethylene oxide

1970 ◽  
Vol 48 (22) ◽  
pp. 3601-3604 ◽  
Author(s):  
S. H. Jones ◽  
E. Whittle
Keyword(s):  
Activation Energy ◽  
Ethylene Oxide ◽  
Published Data ◽  
Methyl Radicals ◽  
Kcal Mole ◽  
Arrhenius Parameters

The reaction between CF3 radicals and ethylene oxide was studied in the range 60–228 °C using CF3I as a radical source. For the reactions,[Formula: see text]we obtain[Formula: see text]where θ = 2.3 RT kcal mole−1Published data of Phibbs and Darwent on the reaction[Formula: see text]have been re-calculated and it is suggested that both the original and re-calculated values of the activation energy E5 are too low. The Arrhenius parameters for the reactions of CF3 and CH3 radicals with ethylene oxide are compared with those for related reactions.

THE REACTION OF METHYL RADICALS WITH FORMALDEHYDE

1959 ◽  
Vol 37 (9) ◽  
pp. 1462-1468 ◽  
Author(s):  
A. R. Blake ◽  
K. O. Kutschke
Keyword(s):  
Activation Energy ◽  
Kinetic Analysis ◽  
Addition Reactions ◽  
Methyl Radicals ◽  
Kcal Mole ◽  
A Value ◽  
Abstraction Reaction ◽  
Butyl Peroxide

The pyrolysis of di-t-butyl peroxide has been reinvestigated and used as a source of methyl radicals to study the abstraction reaction between methyl radicals and formaldehyde. At low [HCHO]/[peroxide] ratios the system was simple enough for kinetic analysis, and a value of 6.6 kcal/mole was obtained for the activation energy. At higher [HCHO]/[peroxide] ratios the system became very complicated, possibly due to the increased importance of addition reactions.

THE VAPOR PHASE PHOTOLYSIS OF HEXAFLUOROACETONE IN THE PRESENCE OF METHANE AND ETHANE

1955 ◽  
Vol 33 (5) ◽  
pp. 743-749 ◽  
Author(s):  
P. B. Ayscough ◽  
J. C. Polanyi ◽  
E. W. R. Steacie
Keyword(s):  
Activation Energy ◽  
Vapor Phase ◽  
Activation Energies ◽  
Methyl Radicals ◽  
Kcal Mole ◽  
Photolytic Decomposition

The photolytic decomposition of hexafluoroacetone by light of wavelength 3130 Å has been used to produce trifluoromethyl radicals for a study of their reactions with methane and ethane. It has been shown that these radicals abstract hydrogen with greater facility than do methyl radicals. The activation energies for the two reactions[Formula: see text]and[Formula: see text]are found to be 10.3 ± 0.5 kcal./mole and 7.5 ±0.5 kcal./mole respectively, if one can assume zero activation energy for the recombination of trifluoromethyl radicals.

THE GAS PHASE REACTION OF METHYL RADICALS WITH HEXAFLUOROACETONE

1957 ◽  
Vol 35 (10) ◽  
pp. 1216-1224 ◽  
Author(s):  
G. O. Pritchard ◽  
E. W. R. Steacie
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Gas Phase ◽  
Steric Factor ◽  
Phase Reaction ◽  
Methyl Radicals ◽  
Kcal Mole ◽  
Gas Phase Reaction

The photolytic and thermal decomposition of azomethane in the presence of hexafluoroacetone produces small amounts of fluorinated products, mainly fluoroform. The mechanism of this and related reactions is discussed. It is concluded that the proposed reaction.[Formula: see text]has an activation energy of about 6 kcal./mole, with a steric factor of about 10−5.

THE PYROLYSIS OF TRIMETHYLTHALLIUM

1965 ◽  
Vol 43 (7) ◽  
pp. 1961-1967 ◽  
Author(s):  
M. G. Jacko ◽  
S. J. W. Price
Keyword(s):  
Activation Energy ◽  
Rate Constant ◽  
Total Pressure ◽  
Flow System ◽  
Total Darkness ◽  
Methyl Radicals ◽  
Kcal Mole ◽  
Homogeneous Process ◽  
Carrier Flow ◽  
Reaction Proceeds

The pyrolysis of trimethylthallium has been studied in a toluene carrier flow system from 458 to 591 °K using total pressures from 5.6 to 33.0 mm. The progress of the reaction was followed by measuring the amount of methane, ethane, ethylene, and ethylbenzene formed and, in 21 runs, by direct thallium analysis. All preparative and kinetic work was carried out in total darkness where possible. A shielded 10 W lamp was used when some illumination was necessary.The decomposition is approximately 80% heterogeneous in an unconditioned vessel and 14–27% heterogeneous in a vessel pretreated with hot 50% HF for 10 min. The reaction proceeds by the simple consecutive release of three methyl radicals. The rate constant depends only slightly on the total pressure in the system so that the activation energy of the homogeneous process, 27.4 kcal/mole, may be equated to D[(CH3)2Tl—CH3].

THE REACTION OF METHYL RADICALS WITH FORMALDEHYDE

1959 ◽  
Vol 37 (4) ◽  
pp. 672-678 ◽  
Author(s):  
S. Toby ◽  
K. O. Kutschke
Keyword(s):  
Activation Energy ◽  
Methyl Radicals ◽  
Kcal Mole ◽  
Formyl Radical ◽  
Temperature Range ◽  
Abstraction Reaction

Azomethane was photolyzed in the presence of up to 30 mole per cent formaldehyde and formaldehyde-d2 at temperatures from 80 °C to 180 °C. The value of the activation energy for the abstraction reaction with methyl radicals was found to be 6.2 kcal mole−1 for CH2O and 7.9 kcal mole−1 for CD2O. The results indicated that the formyl radical was stable over the temperature range studied.

THE REACTIONS OF METHYL RADICALS WITH CYCLOPROPANE, ETHYLENE OXIDE, METHANOL, AND DIMETHYL ETHER

1950 ◽  
Vol 28b (7) ◽  
pp. 395-402 ◽  
Author(s):  
M. K. Phibbs ◽  
B. deB. Darwent
Keyword(s):  
Ethylene Oxide ◽  
Dimethyl Ether ◽  
Activation Energies ◽  
Methyl Radicals ◽  
Kcal Mole ◽  
Photochemical Decomposition

The reactions of methyl radicals, produced by the photochemical decomposition of dimethylmercury, with cyclopropane, ethylene oxide, methanol and dimethyl ether have been investigated between 100° and 250 °C. The following activation energies (kcal. mole−1) for the abstraction of hydrogen from the compounds by methyl radicals were found: cyclopropane, 10.2; ethylene oxide 9.6; methanol, 8.2; and dimethyl ether, 8.0. The probability factors have been shown to be about 10−4 for all the compounds investigated.

THE REACTION OF METHYL RADICALS WITH ISOBUTANE

1953 ◽  
Vol 31 (5) ◽  
pp. 505-510 ◽  
Author(s):  
M. H. Jones ◽  
E. W. R. Steacie
Keyword(s):  
Activation Energy ◽  
Energy Of Activation ◽  
Methyl Radicals ◽  
Kcal Mole ◽  
A Value ◽  
Photochemical Decomposition

An investigation is reported of the reaction of methyl radicals, produced in the photochemical decomposition of azomethane, with isobutane. The energy of activation of this process was found to be 6.7 ± 0.8 kcal./mole, assuming that the combination of methyl radicals has an activation energy of zero. From some experiments with n-butane, a value of 9 ± 1 kcal./mole was obtained.

The mechanism of the photolysis of acetamide

1957 ◽  
Vol 239 (1216) ◽  
pp. 1-15 ◽  
Keyword(s):  
Activation Energy ◽  
Steric Factor ◽  
Primary Process ◽  
Methyl Radicals ◽  
Kcal Mole ◽  
Subsequent Reaction

An investigation of the photolysis of acetamide has been made using light in the 2500 Å region of the spectrum. The main primary process is the breakdown of the molecule into CH 3 and CONH 2 radicals, but this is probably accompanied by a second process yielding CH 3 CN and H 2 O. The methyl radicals react both with acetamide and with CONH 2 radicals to give methane and recombine to give ethane. The CONH 2 radicals may decompose both spontaneously and thermally to give CO and NH 2 radicals. The subsequent reaction of the NH 2 radicals with acetamide gives ammonia. With acetone as a source of methyl radicals, the activation energy for the abstraction of hydrogen by this radical was found to be 9⋅2 kcal/mole and the steric factor ~ 4 x 10 -4 .

Abstraction of hydrogen atoms from bicyclo[2.1.1]hexane by methyl radicals and chlorine atoms: photochlorination of 1-methylbicyclo[2.1.1]hexane

1969 ◽  
Vol 47 (10) ◽  
pp. 1627-1631 ◽  
Author(s):  
R. Srinivasan ◽  
F. I. Sonntag
Keyword(s):  
Activation Energy ◽  
Room Temperature ◽  
Methyl Radicals ◽  
Absolute Rate ◽  
Methyl Radical ◽  
Kcal Mole ◽  
Hydrogen Atoms ◽  
Chlorine Atoms ◽  
Exponential Factor ◽  
Highly Strained

Photolysis of acetone has been used as a source of methyl radicals to study the abstraction of hydrogen atoms from bicyclo[2.1.1]hexane by methyl radicals. The reaction was found to have an activation energy of 10.3 kcal/mole and a pre-exponential factor that is typical of other abstraction reactions. The absolute rate of abstraction of hydrogen atoms from bicyclo[2.1.1]hexane by chlorine atoms at room temperature was measured to be 8.1 × 1010 l mole−1 s−1. The photochlorination of 1-methylbicyclo-[2.1.1]hexane in solution gave both the 1-chloromethyl and 2- or 3-chloro-1-methylbicyclohexanes. The relative rates of attack at the methyl and the 2- or 3- position were determined to be 1:2.1. It is pointed out that the rate parameters for the abstraction of an H atom from bicyclo[2.1.1]hexane by a methyl radical are slower than for cyclopentane, as would be expected for a highly strained hydrocarbon, whereas the abstraction by chlorine is slightly faster than the rate for cyclopentane.

The adsorption of ethylene oxide on silver(I) oxide

1967 ◽  
Vol 20 (5) ◽  
pp. 837
Author(s):  
JA Allen ◽  
PH Scaife
Keyword(s):  
Activation Energy ◽  
Ethylene Oxide ◽  
Heat Of Adsorption ◽  
Entire Temperature Range ◽  
Kcal Mole ◽  
High Coverage ◽  
Temperature Range ◽  
Elovich Equation

The adsorption of ethylene oxide on stabilized silver(I) oxide in the temperature range 210-373% comprises two processes: (i) A non-activated process with a heat of adsorption from 10.7 to 6.9 kcal mole-l depending on the coverage, which persists over the entire temperature range; ��� (ii) an activated process with an activation energy at zero coverage of 22.7 kcal mole-1, which occurs at temperatures greater than 250�K. Reaction between adsorbate and adsorbent ensues above 323%. The generalized Elovich equation has been found to apply to the activated process at high coverage, and an explanation for this is proposed.

Sign in / Sign up

Export Citation Format

Share Document