KINETICS OF THE DECOMPOSITIONS OF ETHANE AND PROPANE SENSITIZED BY AZOMETHANE: THE DECOMPOSITION OF THE NORMAL PROPYL RADICAL

1966 ◽  
Vol 44 (24) ◽  
pp. 2927-2940 ◽  
Author(s):  
M. C. Lin ◽  
K. J. Laidler
Keyword(s):  
Activation Energy ◽  
Satisfactory Agreement ◽  
Rate Constant ◽  
Dissociation Energy ◽  
Low Temperatures ◽  
Heats Of Formation ◽  
Kcal Mole ◽  
Energy Diagram ◽  
A Value ◽  
Kinetics Of

The azomethane-sensitized pyrolysis of ethane was studied at low temperatures from 280 to 350 °C. Measurements were made of initial rates of formation of methane, nitrogen, and butane. From the rate of nitrogen production the rate constant for the azomethane decomposition into 2CH3 + N2 was[Formula: see text]A similar study of the propane decomposition, at temperatures from 260 to 300 °C, led to the value[Formula: see text]in satisfactory agreement. The rate of decomposition of the n-propyl radical into CH3 and C2H4 was obtained by comparing the rates of formation of C2H4 and n-C6H14; the rate constant was[Formula: see text]The activation energy of 31.4 kcal/mole, together with that of 8.9 kcal/mole for the reverse reaction obtained by Brinton, leads to a value of 20.3 kcal/mole for the dissociation energy of n-CH3—CH CH2 at 0 °K, and to a value of 22.8 at 25 °C. The corresponding values for the heats of formation 2of the n-propyl radical are 28.4 kcal/mole at 0 °K, and 23.1 kcal/mole at 25 °C. The dissociation energy of n-CH3CH2CH2—H is deduced to be 99.4 kcal/mole at 0 °K and 99.9 kcal/mole at 25 °C. An energy diagram is constructed for the various reactions of n-C3H7 and i-C3H7.

Ionisierungs- und Auftrittspotentialmessungen an Dialkylsulfoxiden

1975 ◽  
Vol 30 (3) ◽  
pp. 340-346
Author(s):  
Peter Potzinger ◽  
Heinz-Ulrich Stracke ◽  
Wolfgang Küpper ◽  
Klaus Gollnick
Keyword(s):  
Dissociation Energy ◽  
Heats Of Formation ◽  
Kcal Mole ◽  
Dissociation Energies ◽  
Fragment Ions ◽  
A Value

Ionisation- and appearance potentials of some dialkylsulfoxides and their major fragment ions were determined. In addition to the determination of dissociation energies in the ions and heats of formation of the ions and ionic fragments, a value of 66 kcal/mole for the C-S dissociation energy in neutral dialkyl sulfoxides was obtained.

Kinetics of the Mercury-Photosensitized Decomposition of Propane. Part II. Reactions of the Propyl Radicals

1971 ◽  
Vol 49 (4) ◽  
pp. 549-554 ◽  
Author(s):  
M. M. Papic ◽  
K. J. Laidler
Keyword(s):  
Activation Energy ◽  
High Pressure ◽  
Kinetic Parameters ◽  
Dissociation Energy ◽  
Heat Of Formation ◽  
Entropy Changes ◽  
A Value ◽  
Yield Information ◽  
Temperature And Pressure ◽  
Kinetics Of

The results of the previous paper are analyzed to yield information about the reactions of the n-propyl and i-propyl radicals. The various combination and disproportionation reactions are considered. The rate of decomposition of the n-propyl radical was determined as a function of temperature and pressure, and limiting high-pressure and low-pressure kinetic parameters were obtained. The high-pressure activation energy is 32.6 kcal mol−1, and this leads to a value of 24.3 kcal mol−1 for the dissociation energy of the C—C bond in the n-propyl radical, to 22.2 kcal mol−1 for its heat of formation, and to 99.1 kcal mol−1 for the primary C—H dissociation energy in propane. Entropy changes are also calculated from the results.For the decomposition of the i-propyl E∞ = 38.7 kcal mol−1, and this leads to 37.7 kcal mol−1 for the C—H bond dissocation energy in this radical and to 19.3 kcal mol−1 for its heat of formation. The secondary C—H dissociation energy in propane is calculated to be 96.2 kcal mol−1. Corresponding entropy changes are calculated.

scholarly journals The dissociation energy of the C-N bond in benzylamine

1949 ◽  
Vol 198 (1053) ◽  
pp. 285-292 ◽  
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Dissociation Energy ◽  
Heat Of Formation ◽  
Molar Ratio ◽  
Kcal Mole ◽  
First Order ◽  
First Order Kinetics ◽  
Permanent Gases ◽  
Kinetics Of

The kinetics of the thermal decomposition of benzylamine were studied by a flow method using toluene as a carrier gas. The decomposition produced NH 3 and dibenzyl in a molar ratio of 1:1, and small quantities of permanent gases consisting mainly of H 2 . Over a temperature range of 150° (650 to 800° C) the process was found to be a homogeneous gas reaction, following first-order kinetics, the rate constant being expressed by k = 6 x 10 12 exp (59,000/ RT ) sec. -1 . It was concluded, therefore, that the mechanism of the decomposition could be represented by the following equations: C 6 H 5 . CH 2 . NH 2 → C 6 H 5 . CH 2 • + NH 2 •, C 6 H 5 . CH 3 + NH 2 •→ C 6 H 5 . CH 2 • + NH 3 , 2C 6 H 5 . CH 2 •→ dibenzyl, and the experimentally determined activation energy of 59 ± 4 kcal./mole is equal to the dissociation energy of the C-N bond in benzylamine. Using the available thermochemical data we calculated on this basis the heat of formation of the NH 2 radical as 35.5 kcal./mole, in a fair agreement with the result obtained by the study of the pyrolysis of hydrazine. A review of the reactions of the NH 2 radicals is given.

The Kinetics of the Reaction 2C3H6 → C3H5 + C3H7

1973 ◽  
Vol 51 (17) ◽  
pp. 2934-2939 ◽  
Author(s):  
M. Simon ◽  
M. H. Back
Keyword(s):  
Activation Energy ◽  
Rate Constant ◽  
Radical Scavenger ◽  
A Value ◽  
Kinetics Of

An attempt has been made to measure the rate constant for the bimolecular process[Formula: see text]using acetaldehyde as a radical scavenger. The rate constant obtained may be expressed as follows:[Formula: see text]This activation energy corresponds to a value of 36 kcal/mol for ΔHf(allyl).

The kinetics of the reaction between O 2 ( 1 ∆ g ) and ozone

1970 ◽  
Vol 317 (1530) ◽  
pp. 407-416 ◽  
Keyword(s):  
Activation Energy ◽  
Rate Constant ◽  
Room Temperature ◽  
Published Data ◽  
Temperature Range ◽  
A Value ◽  
Kinetics Of

The kinetics of the reaction O 2 ( 1 ∆ g ) + O 3 k 2 → 2O 2 + O have been investigated in the temperature range 195 to 439 K by using the kinetic photo­ionization technique to follow [O 2 ( 1 ∆ g )]. In Arrhenius form, the rate constant, k 2 ,'is given by k 2 = 4.0 ± 1.5 x 10 8 exp (13000 /RT) 1 mol -1 s -1 (joule units) ( = 4.0 ± 1.5 x 10 8 exp (3100/RT) 1 mol -1 s -1 (calorie units)). At room temperature (292 K) k 2 = 2.1 ± 0.3 x 10 6 1 mol -1 s -1 . The activation energy of 13 ± 1.6 kJ mol -1 suggests that there is virtually no barrier to the reaction other than that provided by its endothermicity (12.1 kJ mol -1 ). The results are used to derive, from pre­viously published data, a value of the rate constant for the reaction O + O 3 k 3 → 2O 2 of 4 ± 2 x 10 6 1 mol -1 s -1 at room temperature.

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.

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.

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.

A thermodynamic study of the dimerization of cyclopentadiene

1968 ◽  
Vol 21 (7) ◽  
pp. 1789 ◽  
Author(s):  
AG Turnbull ◽  
HS Hull
Keyword(s):  
Liquid Phase ◽  
Rate Constant ◽  
Vapour Pressure ◽  
Boiling Point ◽  
Strain Energy ◽  
Order Rate Constant ◽  
Adiabatic Calorimeter ◽  
Thermodynamic Study ◽  
Heats Of Formation ◽  
Kcal Mole

The heat of dimerization of cyclopentadiene to endo-dicyciopentadiene in the liquid phase at 25� was measured in an adiabatic calorimeter to be -9.22 � 0.3 kcal/mole monomer. The rate of dimerization in the liquid phase at 25� was followed with a dilatometer and the initial second-order rate constant found to be 4.99 x 10-5. mole-l min-l. The vapour pressure of endo-dicyclopentadiene, measured by a boiling point method in the range 77.5-149.6�, gave the relation (p in torr): RInp ? 11342/T -2.6505In T + 54.7855 The standard heats of formation of solid, 31.1 � 0.5 kcal/mole, and gaseous, 42.2 � 0. 6 kcal/mole, endo-dicyclopentadiene were derived, and the strain energy and dimerization equilibria discussed.

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.

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