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.

Synthesis of Sic Fine Particles by Gas-Phase Reaction Under Short-Time Microgravity

1992 ◽  
Vol 286 ◽  
Author(s):  
Takeshi Okutani ◽  
Yoshinori Nakata ◽  
Masaakt Suzuki ◽  
Yves Maniette ◽  
Nobuyoshi Goto ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Heat Source ◽  
Size Distribution ◽  
Gas Phase ◽  
Fine Particles ◽  
Rapid Heating ◽  
Exothermic Reaction ◽  
Phase Reaction ◽  
Gas Phase Reaction ◽  
Short Time

ABSTRACTSiC fine particles were synthesized by the gas-phase thermal decomposition of tetramethylsilane (Si(CH3)4) in hydrogen under microgravity of 10−4G for 10 sec. Rapid heating to the temperature over 800°C which is required for thermal decomposition of Si(CH3)4) under short-time microgravity was attained using a chemical oven where the heat of exothermic reaction of combustion synthesis of Ti-A1-4B composites was used as the heat source. Monodisperse and spherical SiC fine particles were synthesized under microgravity, whereas aggregates of SiC fine particles were synthesized under 1 G gravity. The SiC particles synthesized under microgravity (150-200 nm) were bigger in size and narrower in size distribution than those under 1 G gravity (100-150 nm).

Direct time-resolved study of the kinetics of the gas-phase reaction of germylene with triethylgermane: a negative activation energy for the Ge–H insertion process

1997 ◽  
Vol 7 (3) ◽  
pp. 87-88 ◽  
Author(s):  
Rosa Becerra ◽  
Sergei E. Boganov ◽  
Mikhail P. Egorov ◽  
Oleg M. Nefedov ◽  
Robin Walsh
Keyword(s):  
Activation Energy ◽  
Gas Phase ◽  
Phase Reaction ◽  
Time Resolved ◽  
Gas Phase Reaction ◽  
Kinetics Of ◽  
Insertion Process

scholarly journals On Apparent Activation Energy of Solid-Catalyzed Gas-Phase Reaction

1971 ◽  
Vol 35 (4) ◽  
pp. 455-461,a1
Author(s):  
Shigeaki Kasaoka ◽  
Yusaku Sakata
Keyword(s):  
Activation Energy ◽  
Apparent Activation Energy ◽  
Gas Phase ◽  
Phase Reaction ◽  
Gas Phase Reaction

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.

Bestimmung der Bildungsenthalpie von Nitroxychlorid (Chlornitrat, NO3Cl) als Beitrag zur Deutung der Kinetik des thermischen NO3Cl-Zerfalls in der Gasphase und in der Lösungsphase / Determination of the Enthalpy of Formation of nitroxy Chloride (Chlorine Nitrate, NO3Cl). A Contribution to the Interpretation of the Kinetics of the Thermal Decomposition of NO3Cl in the Gas Phase and in Solution

1974 ◽  
Vol 29 (2) ◽  
pp. 200-210 ◽  
Author(s):  
H.-D. Knauth ◽  
H. Martin ◽  
W. Stockmann
Keyword(s):  
Thermal Decomposition ◽  
Gas Phase ◽  
Enthalpy Of Formation ◽  
Standard Enthalpy Of Formation ◽  
Phase Reaction ◽  
Chlorine Nitrate ◽  
Chain Reactions ◽  
Gas Phase Reaction ◽  
Inert Solvent

The dissociation energy values ⊿H0298(ClO- NO2) = 25.87 kcal mol-1 and ⊿H00(ClO-NO2),0 = 24.8 kcal mol-1 were derived from the standard enthalpy of formation of nitroxy chloride (NO3CI) ⊿Hf0 = 6.28 kcalmol-1 which has been determined from the reaction enthalpy of the gas phase reaction NOCI + NO3CI = 2 NO2 + Cl2. With the help of these data it was possible to show that in the thermal decomposition of NO3Cl, for which the overall reaction is NO3Cl = NO2 +½O2 + ½Cl2. at temperatures around 100 °C the equilibrium NO3Cl ⇄ NO2 + OCl is established. At the beginning of the reaction, there exists such a high OCl concentration that the decomposition occurs practically exclusively by the reactions OCl + OCl + M ⇄Cl2O2 + M, Cl2O2 + M → Cl2 + O2+M and OCl + OCl → Cl + OOCl, the last of which is followed by Cl-consuming reaction steps, e.g. CI + NO3CI → NO3 + Cl2, apparently initiating chain reactions. The reaction step NO2 + NO3Cl → NO3 + NO2Cl, postulated from an investigation of the kinetics in a nono-polar inert solvent, and its daughter reactions probably occur for the gas phase reaction as well.

Kinetics of Decomposition of Titanium Tetraiodide

1963 ◽  
Vol 16 (1) ◽  
pp. 66
Author(s):  
KM Bowling
Keyword(s):  
Gas Phase ◽  
Electrical Conductance ◽  
Phase Reaction ◽  
Kcal Mole ◽  
Gas Phase Reaction ◽  
First Order ◽  
Kinetics Of Decomposition ◽  
Vapour Concentration ◽  
Counter Current ◽  
Kinetics Of

����� The rate of growth of an incandescent filament exposed to a steady stream of titanium tetraiodide vapour was determined from changes in the electrical conductance of the filament, and used to calculate the rate of decomposition of titanium tetraiodide at 1100-1500�C and at various vapour pressures. The method used eliminates the effects of titanium evaporation, counter-current gaseous diffusion, and the iodide synthesis reaction, which have influenced previous work.�The results show that the rate of decomposition is proportional to the vapour concentration but independent of the surface area for a given length of filament. The decomposition rate varies with temperature according to an Arrhenius-type relationship, leading to a provisional estimate for the energy of activation of 28.6 kcal/mole. Under suitable conditions high deposition rates are obtained. The decomposition appears to proceed as a first-order, homogeneous, gas-phase reaction in a hot reaction zone around the filament, rather than heterogeneously on the surface.

scholarly journals Thermochemistry Is Not a Lower Bound to the Activation Energy of Endothermic Reactions:  A Kinetic Study of the Gas-Phase Reaction of Atomic Chlorine with Ammonia†

2006 ◽  
Vol 110 (21) ◽  
pp. 6844-6850 ◽  
Author(s):  
Yide Gao ◽  
I. M. Alecu ◽  
P-C. Hsieh ◽  
Brad P. Morgan ◽  
Paul Marshall ◽  
...  
Keyword(s):  
Activation Energy ◽  
Lower Bound ◽  
Kinetic Study ◽  
Gas Phase ◽  
Phase Reaction ◽  
Gas Phase Reaction ◽  
Endothermic Reactions ◽  
Atomic Chlorine

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 .

Activation energy for the gas phase reaction of hydrogen atoms with carbon monoxide

1973 ◽  
Vol 59 (9) ◽  
pp. 5199-5200 ◽  
Author(s):  
H. Y. Wang ◽  
J. A. Eyre ◽  
Leon M. Dorfman
Keyword(s):  
Activation Energy ◽  
Carbon Monoxide ◽  
Gas Phase ◽  
Phase Reaction ◽  
Hydrogen Atoms ◽  
Gas Phase Reaction

The thermal decompositions of carbamates. II. Methyl N-methylcarbamate

1972 ◽  
Vol 25 (7) ◽  
pp. 1453 ◽  
Author(s):  
NJ Daly ◽  
F Ziolkowski
Keyword(s):  
Activation Energy ◽  
Transition State ◽  
Gas Phase ◽  
Rate Constants ◽  
Volume Ratio ◽  
Reaction Vessel ◽  
Phase Reaction ◽  
Methyl Isocyanate ◽  
Gas Phase Reaction ◽  
First Order

Methyl N-methyloarbamate decomposes in the range 370-422� to give methyl isocyanate and methanol. The reaction is first order in carbamate, and the variation of the rate constants with temperature is given by the equation. k = 1012.39 exp(-4806O/RT) (s-l; activation energy in cal mol-l) Rate constants are unaffected by the addition of isobutene or by increase in the surface to volume ratio of the reaction vessel. The addition of alcohols or amines does not reverse the process. The decomposition is considered to be a homogeneous, unimolecular gas-phase reaction, probably proceeding through a four-centred transition state.

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