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.

Decomposition of BrO studied by kinetic spectroscopy

1970 ◽  
Vol 48 (22) ◽  
pp. 3487-3490 ◽  
Author(s):  
J. Brown ◽  
George Burns
Keyword(s):  
Activation Energy ◽  
Total Pressure ◽  
Reaction Rate ◽  
Second Order ◽  
Kcal Mole ◽  
Kinetic Spectroscopy ◽  
Reaction Proceeds ◽  
One Step ◽  
Kinetics Of ◽  
Activated Complex

Kinetics of BrO decomposition was studied between 293 and 673 °K using the technique of kinetic spectroscopy. At 293 °K the reaction rate is second order with respect to BrO and is independent of [Br2], [O2], and total pressure of diluent gas. The activation energy for decomposition obtained from rate measurements between 293 and 450 °K is 0.65 ± 0.05 kcal/mole. Above 450 °K this activation energy appears to increase to 4.5 kcal/mole. It is shown that, although kinetically the ClO and BrO decompositions are similar, the mechanism for BrO decomposition below 450 °K is much simpler than that of ClO. The reaction proceeds, most likely, via one step: 2 BrO → 2 Br + O2, with Br2O2 being an activated complex, which has either linear or staggered configuration. ClO and BrO decomposition is compared with [Formula: see text] reaction.

Vulcanization of Elastomers. 23. The Chemical Kinetics of Vulcanization Reactions and The Physical Properties of The Vulcanizates. I

1960 ◽  
Vol 33 (2) ◽  
pp. 335-341
Author(s):  
Walter Scheele ◽  
Karl-Heinz Hillmer
Keyword(s):  
Activation Energy ◽  
Physical Properties ◽  
Chemical Kinetics ◽  
Kcal Mole ◽  
First Order ◽  
Equilibrium Swelling ◽  
Kinetics Of ◽  
Kinetics Of Vulcanization ◽  
Limiting Value ◽  
Good Agreement

Abstract As a complement to earlier investigations, and in order to examine more closely the connection between the chemical kinetics and the changes with vulcanization time of the physical properties in the case of vulcanization reactions, we used thiuram vulcanizations as an example, and concerned ourselves with the dependence of stress values (moduli) at different degrees of elongation and different vulcanization temperatures. We found: 1. Stress values attain a limiting value, dependent on the degree of elongation, but independent of the vulcanization temperature at constant elongation. 2. The rise in stress values with the vulcanization time is characterized by an initial delay, which, however, is practically nonexistent at higher temperatures. 3. The kinetics of the increase in stress values with vulcanization time are both qualitatively and quantitatively in accord with the dependence of the reciprocal equilibrium swelling on the vulcanization time; both processes, after a retardation, go according to the first order law and at the same rate. 4. From the temperature dependence of the rate constants of reciprocal equilibrium swelling, as well as of the increase in stress, an activation energy of 22 kcal/mole can be calculated, in good agreement with the activation energy of dithiocarbamate formation in thiuram vulcanizations.

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.

Insect blood-brain barrier: a radioisotope study of the kinetics of exchange of a liposoluble molecule (n-butanol)

1976 ◽  
Vol 64 (1) ◽  
pp. 119-130
Author(s):  
M. V. Thomas
Keyword(s):  
Activation Energy ◽  
Temperature Sensitivity ◽  
Nerve Cord ◽  
Previous Investigation ◽  
Time Course ◽  
Kcal Mole ◽  
Similar Time ◽  
Kinetics Of ◽  
Butanol Concentration ◽  
Good Agreement

About 90% of the butanol uptake by the cockroach abdominal nerve cord washed out with half-times of a few seconds, in good agreement with an electrophysiological estimate, and the temperature sensitivity suggested an activation energy of 3 Kcal mole-1. The remaining activity washed out far more slowly, with a similar time course to that observed in a previous investigation which had not detected the fast fraction. Its size was similar to the non-volatile uptake, and was considerably affected by the butanol concentration and incubation period. It apparently consisted of butanol metabolites, which could be detected by chromatography.

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.

Kinetics of the addition of acids to olefins with and without boron fluoride catalysis

1967 ◽  
Vol 45 (1) ◽  
pp. 11-16 ◽  
Author(s):  
G. A. Latrèmouille ◽  
A. M. Eastham
Keyword(s):  
Activation Energy ◽  
Acetic Acid ◽  
Apparent Activation Energy ◽  
Trifluoroacetic Acid ◽  
Similar Rate ◽  
Ethylene Dichloride ◽  
Kcal Mole ◽  
Rate Law ◽  
Boron Fluoride ◽  
Kinetics Of

Isobutene reacts readily with excess trifluoroacetic acid in ethylene dichloride solution at ordinary temperatures to give t-butyl trifluoroacetate. The rate of the reaction is given, within the range of the experiments, by the expression d[ester]/dt = k[acid]2[olefin], and the apparent activation energy is about 6 kcal/mole. The rate of addition is markedly dependent on the strength of the reacting acid and is drastically reduced in the presence of mildly basic materials, such as dioxane. The boron fluoride catalyzed addition of acetic acid to 2-butene can be considered to follow a similar rate law, i.e. d[ester]/dt = k[acid·BF3]2[olefin], but only if some assumptions are made about the position of the equilibrium [Formula: see text]since only the 1:1 complex is reactive.

Quantum yield and total pressure effect in perfluoroglutaric anhydride photolysis in the gas phase

1985 ◽  
Vol 30 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Gerardo A. Argüello ◽  
Esther R. de Staricco ◽  
Eduardo H. Staricco
Keyword(s):  
Quantum Yield ◽  
Gas Phase ◽  
Total Pressure ◽  
Pressure Effect

Chemical Vapor Deposition of SiO2 from Ozone-Organosilane Mixtures near Atmospheric Pressure

1992 ◽  
Vol 282 ◽  
Author(s):  
K. V. Guinn ◽  
J. A. Mucha
Keyword(s):  
Activation Energy ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Atmospheric Pressure ◽  
Chemical Vapor ◽  
Zero Order ◽  
Kcal Mole ◽  
Consumption Ratio ◽  
Zero Order Kinetics ◽  
Kinetics Of

ABSTRACTThe kinetics of deposition of SiO2 by the reaction of tetramethylsilane (TMS) with ozone (O3) has been studied over the temperature range 180 – 380° C and compared with available data for the same process using tetraethoxysilane (TEOS). Both processes exhibit the same activation energy (17 kcal/mole) below 300 ° C which falls-off at higher temperatures due to transport limitations. Transition from first- to zero-order kinetics occurs with increasing concentrations of TMS and O3, which gives an overall O3/TMS consumption ratio of 10 at 258° C and5 at 325° C. TEOS is estimated to be 5 times more reactive than TMS above 300° C and over 10 times more reactive in the kinetically-limited regime below 300° C. Results suggest that O3-induced SiO2 deposition proceeds via surface reactions and is limited by heterogeneous decomposition of ozone.

scholarly journals Frequency Dependent Kinetics of the CW CO2 Laser Induced Reaction of CF3CF2Cl

1987 ◽  
Vol 7 (5-6) ◽  
pp. 271-277
Author(s):  
R. N. Zitter ◽  
D. F. Koster ◽  
N. Siddiqua
Keyword(s):  
Activation Energy ◽  
Absorption Band ◽  
Co2 Laser ◽  
Laser Frequency ◽  
Kcal Mole ◽  
Band Center ◽  
Laser Frequencies ◽  
Cw Co2 Laser ◽  
Kinetics Of ◽  
Induced Reaction

Kinetics of the decomposition of CF3CF2Cl at 50 torr by a cw CO2 laser have been studied over a range of laser frequencies extending 36 cm−1 below an absorption band center at 980 cm−1. At constant translational temperature, the change in the rate constant with laser frequency is a factor of 100, comparable to the effect previously observed in CF2ClCF2Cl. Arrhenius plots show an activation energy of 86.2 kcal/mole, independent of frequency.

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