THE GAS PHASE PHOTOLYSIS OF ACETIC AND PROPIONIC ANHYDRIDE

1956 ◽  
Vol 34 (12) ◽  
pp. 1709-1713 ◽  
Author(s):  
P. Ausloos
Keyword(s):  
Activation Energy ◽  
Acetic Anhydride ◽  
Gas Phase ◽  
Temperature Region ◽  
Equal Probability ◽  
Kcal Mole ◽  
Propionic Anhydride ◽  
Abstraction Reaction ◽  
Photochemical Decomposition

The photolysis of acetic anhydride has been reinvestigated in the temperature region from 30 to 195 °C. Two primary processes occur with about equal probability:[Formula: see text]Analogous primary processes have been proposed for the photochemical decomposition of propionic anhydride.The abstraction reaction:[Formula: see text]is of importance, and the results indicate that it has an activation energy of about 9.6 kcal./mole.

POLYMÉRISATION PAR LES RAYONS-X DU CHLORURE DE VINYLE À L'ÉTAT DE VAPEUR

1963 ◽  
Vol 41 (6) ◽  
pp. 1578-1587 ◽  
Author(s):  
Jan A. Herman ◽  
Pierre M. Hupin
Keyword(s):  
Activation Energy ◽  
Gas Phase ◽  
Average Molecular Weight ◽  
Negative Temperature ◽  
Solid Polymer ◽  
X Rays ◽  
Kcal Mole ◽  
Rate Of Polymerization ◽  
G Value ◽  
Termination Process

The polymerization of vinyl chloride in the gas phase by X rays gives a solid polymer of 1140 average molecular weight. The G value of monomer disappearance varies from 100 to 400 and depends on pressure and temperature. From the measure of the rate of polymerization it was possible to deduce the activation energy of the chain propagation steps: 2.5 kcal/mole, and that of the hindered termination process: 7.4 kcal/mole. The negative temperature co-efficient of the polymerization is explained by the importance of this hindered termination process.

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 Langmuir-Hinshelwood Reaction between Oxygen and CO at Ir(111) Surfaces

1979 ◽  
Vol 34 (1) ◽  
pp. 81-88 ◽  
Author(s):  
J. Küppers ◽  
A. Plagge
Keyword(s):  
Activation Energy ◽  
Computer Program ◽  
Apparent Activation Energy ◽  
Gas Phase ◽  
Close Agreement ◽  
Reaction Path ◽  
Kcal Mole ◽  
Reaction Step ◽  
Per Se ◽  
Reaction Processes

Abstract The reaction of oxygen and CO to form CO2 has been investigated using an Ir (111) surface as an acting catalyst. Both instationary and stationary reaction processes have been established via separate gas exposing techniques. The instationary reaction process, achieved from coadsorbed CO and O which per se is an LH reaction is found to be controlled by an apparent activation energy of 10.7 kcal/mole. The stationary reaction with both CO and O2 continuously present in the gas phase has been simulated using a proper computer program, involving both LH and ER reaction steps. By comparison with experimental results, close agreement is found when ruling out any ER reaction step from the reaction path.

Gas phase photochlorination of perfluorocyclohexene

1969 ◽  
Vol 47 (6) ◽  
pp. 1067-1069 ◽  
Author(s):  
J. J. Cosa ◽  
C. A. Vallana ◽  
E. H. Staricco
Keyword(s):  
Activation Energy ◽  
Quantum Yield ◽  
Gas Phase ◽  
Photochemical Reaction ◽  
Total Pressure ◽  
Square Root ◽  
Kcal Mole ◽  
Kinetics Of

The kinetics of the gas phase photochemical reaction between perfluorocyclohexene and chlorine was studied between 10 and 50 °C. The system was irradiated with light of 4360 Å. The rate of the photochlorination was independent of the perfluorocyclohexene pressure and of the total pressure. It was found to be proportional to the first power of the pressure of Cl2 and to the square root of the intensity of absorbed light. At 30 °C, the quantum yield was found to be 200 when the initial Cl2 pressure was 100 Torr, and intensity of light absorbed 9.89 × 10−9 einstein l−1s−1.An activation energy of 5.1 kcal/mole could be assigned to the reaction C6F10Cl + Cl2.

THE THERMAL DECOMPOSITION OF METHYL HYDROPEROXIDE

1965 ◽  
Vol 43 (8) ◽  
pp. 2236-2242 ◽  
Author(s):  
Alexander D. Kirk
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Gas Phase ◽  
Rate Constants ◽  
Dimethyl Phthalate ◽  
Kcal Mole ◽  
First Order ◽  
Methyl Hydroperoxide ◽  
Expected Values ◽  
Homogeneous Decomposition

The thermal decomposition of methyl hydroperoxide has been studied in solution and in the gas phase. The decomposition was found to be partly heterogeneous in solution in dimethyl phthalate and no reliable rate constants were obtained. Use of the toluene carrier method for the gas phase work enabled measurement of the rate constant for the homogeneous decomposition. The first order rate constants obtained range from 0.19 s−1 at 292 °C to 1.5 s−1 at 378 °C, leading to log A, 11± 2, and activation energy, 32 ± 5 kcal/mole. These results are compared with the expected values of log A, 13–14, and activation energy, 42 kcal/mole. The significance of these findings is discussed.

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 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 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.

PHOTOLYSIS OF MERCURY DIMETHYL

1953 ◽  
Vol 31 (7) ◽  
pp. 631-637 ◽  
Author(s):  
Richard E. Rebbert ◽  
E. W. R. Steacie
Keyword(s):  
Activation Energy ◽  
Kcal Mole ◽  
Temperature Range ◽  
Abstraction Reaction

The photolysis of mercury dimethyl was investigated over the temperature range from 125° to 250 °C. The results indicate that methane is formed only by an abstraction reaction and ethane is formed only by recombination, at least under the conditions used in these experiments. It is concluded that the activation energy of the reaction[Formula: see text]is 10.8 ± 0.3 kcal./mole.

Gas phase photochemical decomposition of 1-bromopropane

1981 ◽  
Vol 59 (12) ◽  
pp. 1827-1833 ◽  
Author(s):  
Stuart G. Bayliss ◽  
Robert L. Failes ◽  
Jacob S. Shapiro
Keyword(s):  
Activation Energy ◽  
Light Intensity ◽  
Gas Phase ◽  
Hydrogen Bromide ◽  
Bromine Atom ◽  
Incident Light ◽  
Incident Light Intensity ◽  
Allyl Radical ◽  
Photochemical Decomposition ◽  
Overall Kinetics

The gas phase photochemical decomposition of 1-bromopropane (lbp) was studied over the temperature range 374–483 K and the pressure range10–95 kPa. Within these ranges the overall kinetics are expressed by:[Formula: see text]where I0 is the incident light intensity. The principal propagation step involves the abstraction of the secondary hydrogen by a bromine atom leading to two major products: propene and hydrogen bromide. Termination involving allyl radical is postulated, a feature that sets this photolysis apart from those of ethyl and neopentyl bromides. The overall activation energy is 33.8 ± 0.8 kJ mol−1 and it leads to Arrhenius parameters for the propagation step [3] of Ea = 29.7 kJ mol−1 and log10A = 9.1 (A in dm3 mol−1 s−1).[Formula: see text]

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