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.

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 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].

Notizen:Kinetics of Ester-interchange between Methyl Acetate and Ethanol

1972 ◽  
Vol 27 (10) ◽  
pp. 1529-1530 ◽  
Author(s):  
T. Rao ◽  
B. Gandhe
Keyword(s):  
Reaction Rate ◽  
Methyl Acetate ◽  
Second Order ◽  
Energy Of Activation ◽  
Chromatographic Technique ◽  
Kcal Mole ◽  
Specific Reaction Rate ◽  
Ester Interchange ◽  
Specific Reaction ◽  
Kinetics Of

Abstract Kinetics of ester-interchange between methyl acetate and ethanol has been studied in the range 80 - 105°, using gas chromatographic technique. The reaction is of the second order, and the specific reaction rate is 29.6-10-8 l/mole-sec at 105°. The energy of activation is 16.7 kcal/mole and the en-tropy of activation is -44.3 cal/mole-deg.

Kinetics of the reaction of methyl iodide with sulfite and thiosulfate ions in aqueous solution

1969 ◽  
Vol 47 (24) ◽  
pp. 4537-4541 ◽  
Author(s):  
R. A. Hasty ◽  
S. L. Sutter
Keyword(s):  
Activation Energy ◽  
Methyl Iodide ◽  
Reaction Rate ◽  
Reaction Rate Constant ◽  
Order Reaction ◽  
Second Order Reaction ◽  
Kcal Mole ◽  
Rate Of Reaction ◽  
Kinetics Of ◽  
Sulfite Ion

The rate of reaction of methyl iodide with sulfite ion is determined. In addition, the rate of reaction of methyl iodide with thiosulfate ion is reexamined and the rate of reaction of methyl iodide with bisulfite ion is estimated. A pronounced effect of ionic strength on the reaction rate in the methyl iodide – sulfite ion system is observed, this effect does not occur in the methyl iodide – thiosulfate ion system. The second order reaction rate constant and activation energy for the reaction of methyl iodide with the respective nucleophiles are: SO32−, 4.4 × 10−2M−1 s−1, 18.6 kcal mole−1; HSO3−, 1 × 10−3M−1 s−1, 18.4 kcal mole−1; and S2O32− 3.1 × 10−2M−1 s−1, 19.4 kcal mole−1.

The kinetics of formation of ruthenium(II) nitrogen complexes

1970 ◽  
Vol 48 (11) ◽  
pp. 1639-1644 ◽  
Author(s):  
Clive M. Elson ◽  
I. J. Itzkovitch ◽  
John A. Page
Keyword(s):  
Activation Energy ◽  
Order Rate Constant ◽  
Second Order ◽  
Kcal Mole ◽  
Potential Reduction ◽  
First Order ◽  
Kinetics Of Formation ◽  
Controlled Potential ◽  
Kinetics Of ◽  
Electrolyte Ph

The formation of nitrogen monomers by the reaction of Ru(NH3)5(H2O)2+ and cis-Ru(NH3)4(H2O)22+ with N2 has been shown to be first order in N2 and second order overall. The formation of bridging N2 dimers by the reaction of the ruthenium(II) pentaammine and tetraammine with the monomers has been shown to be second order overall.The reactions were studied in a H2SO4–K2SO4 electrolyte pH 3.3, μ = 0.30. The ruthenium(II) species were prepared by controlled potential reduction of known ruthenium(III) species at −0.50 V at a Hg cathode. The reactions of the reduced species with N2 or the monomers were followed spectrophotometrically.The second order rate constant at 25 °C and the activation energy for the substrate Ru(NH3)5(H2O)2+ with the respective nucleophiles are: N2, 8.0 × 10−2 M−1 s−1, 22.0 ± 0.1 kcal/mole; Ru(NH3)5N22+, 3.6 × 10−2 M−1 s−1, 19.9 ± 0.5 kcal/mole; Ru(NH3)4(H2O)N22+, 2.7 × 10−2 M−1 s−1, 20.4 ± 0.8 kcal/mole. For the substrate cis-Ru(NH3)4(H2O)22+ the values are: N2, 1.0 × 10−1 M−1 s−1, 20.4 ± 0.2 kcal/mole; Ru(NH3)5N22+, 6.8 × 10−2 M−1 s−1, 18.2 ± 0.1 kcal/mole; Ru(NH3)4(H2O)N22+, 7.2 × 10−2 M −1 s−1, 17.1 ± 0.2 kcal/mole.

Vulcanization of Elastomers. 22. Thermal Vulcanization of Synthetic Rubbers. I

1959 ◽  
Vol 32 (4) ◽  
pp. 962-975
Author(s):  
Walter Scheele ◽  
Hans Dieter Stemmer
Keyword(s):  
Activation Energy ◽  
Second Order ◽  
Crosslinking Reaction ◽  
Molecular Fragments ◽  
Kcal Mole ◽  
First Order ◽  
Disulfide Content ◽  
Kinetics Of ◽  
Stable Combination ◽  
Limiting Value

Abstract In this work, the kinetics of the thermal vulcanization of Perbunan were studied with and without additives. The following results were obtained : 1. The pure thermal vulcanization of Perbunan is a very slow process which obeys a second order rate law. A limiting value of the crosslinking (reciprocal limit of equilibrium swelling) is reached, which limit is independent of the temperature. The activation energy is 23.3 kcal/mole. 2. The thermal vulcanization can be inhibited by hydroquinone but not by benzoquinone. 3. The thermal vulcanization of Perbunan can be considerably accelerated by MBTS, and other materials, and the reaction also follows a second order course. The activation starts suddenly after the expiration of an induction period, which decreases with increase in temperature. The activation energy is about 27 kcal/mole. 4. In a thermal vulcanization accelerated with MBTS, a portion of the MBTS is changed over into MBT ; the amount changed is independent of temperature. Perbunan takes up MBTS in the form of molecular fragments, in stable combination. 5. The reduction in MBTS (which falls to zero) and the increase in MBT follow a first order reaction and have the same activation energy which is also identical with the energy of activation of the accelerated crosslinking. The formation of MBT is the slower of the two reactions. 6. The rate constants for the decrease in MBTS and for the increase in MBT are independent of the starting amount of MBTS, and hence we consider that this is a unimolecular process (homolysis). 7. The rate constant for the second order crosslinking reaction increases with the square root of the initial benzothiazolyl disulfide content. 8. It is indicated that the above data must be explained, with the aid of experience in the realm of polymerization kinetics. The investigations are being continued.

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.

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.

scholarly journals Analysis of the Kinetics of Swimming Pool Water Reaction in Analytical Device Reproducing Its Circulation on a Small Scale

Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4820 ◽  
Author(s):  
Wojciech Kaczmarek ◽  
Jarosław Panasiuk ◽  
Szymon Borys ◽  
Aneta Pobudkowska ◽  
Mikołaj Majsterek
Keyword(s):  
Activation Energy ◽  
Water Quality ◽  
Rate Constant ◽  
Reaction Rate ◽  
Reaction Rate Constant ◽  
Small Scale ◽  
Pool Water ◽  
Swimming Pool Water ◽  
Kinetics Of ◽  
Analytical Device

The most common cause of diseases in swimming pools is the lack of sanitary control of water quality; water may contain microbiological and chemical contaminants. Among the people most at risk of infection are children, pregnant women, and immunocompromised people. The origin of the problem is a need to develop a system that can predict the formation of chlorine water disinfection by-products, such as trihalomethanes (THMs). THMs are volatile organic compounds from the group of alkyl halides, carcinogenic, mutagenic, teratogenic, and bioaccumulating. Long-term exposure, even to low concentrations of THM in water and air, may result in damage to the liver, kidneys, thyroid gland, or nervous system. This article focuses on analysis of the kinetics of swimming pool water reaction in analytical device reproducing its circulation on a small scale. The designed and constructed analytical device is based on the SIMATIC S7-1200 PLC driver of SIEMENS Company. The HMI KPT panel of SIEMENS Company enables monitoring the process and control individual elements of device. Value of the reaction rate constant of free chlorine decomposition gives us qualitative information about water quality, it is also strictly connected to the kinetics of the reaction. Based on the experiment results, the value of reaction rate constant was determined as a linear change of the natural logarithm of free chlorine concentration over time. The experimental value of activation energy based on the directional coefficient is equal to 76.0 [kJ×mol−1]. These results indicate that changing water temperature does not cause any changes in the reaction rate, while it still affects the value of the reaction rate constant. Using the analytical device, it is possible to constantly monitor the values of reaction rate constant and activation energy, which can be used to develop a new way to assess pool water quality.

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.

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