Kinetics of the initial stage of initiated thermal oxidation of caprolactam and N-octylbutyramide

1981 ◽  
Vol 46 (11) ◽  
pp. 2650-2656 ◽  
Author(s):  
Božena Lánská ◽  
Ludvig Michailovich Postnikov ◽  
Albert Leonidovich Aleksandrov ◽  
Jan Šebenda
Keyword(s):  
Liquid Phase ◽  
Thermal Oxidation ◽  
Radical Reaction ◽  
Second Order ◽  
Peroxy Radicals ◽  
Oxidation Reactions ◽  
Temperature Range ◽  
Initial Stage ◽  
A Chain ◽  
Kinetics Of

The thermal oxidation of ε-caprolactam or N-octylbutyramide in the liquid phase is a chain radical reaction. In the initial stage, the only reaction product is the corresponding amide hydroperoxide, formed from peroxy radicals by a second-order termination reaction. The rates of thermal oxidation reactions initiated with 7,7'-dicumenyl peroxide or 1,1'-azodi(cyclohexanecarbonitrile) and the rates of initiation reactions were measured in the temperature range 80-130 °C. Using the values thus obtained, the ratios of rates of the propagation and termination steps, k2 . k6-1/2, characterizing the oxidizability compounds, were calculated.

The pulse radiolysis of 1-propanol at 147 to 300 K

1976 ◽  
Vol 54 (4) ◽  
pp. 531-536 ◽  
Author(s):  
L. Gilles ◽  
A. W. Boyd
Keyword(s):  
Temperature Dependence ◽  
Pulse Radiolysis ◽  
Radical Reaction ◽  
Second Order ◽  
Uv Absorption ◽  
Solvated Electron ◽  
Temperature Range ◽  
Electron Pulses ◽  
Kinetics Of

Using ∼20 ns electron pulses the spectra and kinetics of the electron and an absorption in the uv in 1-propanol have been determined at temperatures from 147 to 300 K. The uv absorption is attributed to the hydroxy propyl radical, CH3CH2ĊHOH; it is formed within ∼20 ns over this temperature range and disappears by second order kinetics. The results for the formation of the solvated electron are in agreement with those of Baxendale and Wardman. The temperature dependence of both the radical–radical reaction and the reaction of the solvated electron with N2O is very nearly the same as that of T/η.

Kinetics and mechanism of oxidation of DL-α-alanine by permanganate ion in acid perchlorate media

1991 ◽  
Vol 69 (12) ◽  
pp. 2018-2023 ◽  
Author(s):  
Refat M. Hassan
Keyword(s):  
Amino Acids ◽  
Ionic Strength ◽  
Acid Solution ◽  
Second Order ◽  
Perchloric Acid Solution ◽  
Oxidation Reduction ◽  
Initial Stage ◽  
Aqueous Perchloric Acid ◽  
Mechanism Of Oxidation ◽  
Kinetics Of

The kinetics of permanganate oxidation of DL-α-alanine in aqueous perchloric acid solution at a constant ionic strength of 2.0 mol dm−3 has been investigated spectrophotometrically. The reaction was found to show second-order kinetics overall with respect to each of the reactants in the slow initial stage; the second-order kinetics are not, however, maintained throughout the relatively fast final stage of reaction. The added salts lead to the prediction that Mn(III) and (or) Mn(IV) play a very important role in the reaction kinetics. A tentative mechanism consistent with the kinetics is discussed. Key words: kinetics, oxidation, reduction, amino acids, permanganate.

scholarly journals On the Mechanism of Methane Conversion in the Nonсatalytic Processes of Its Thermal Pyrolysis and Steam and Carbon Dioxide Reforming

2021 ◽  
Author(s):  
E. Busillo ◽  
V. I. Savchenko ◽  
V. S. Arutyunov
Keyword(s):  
Carbon Dioxide ◽  
Methane Conversion ◽  
Carbon Dioxide Reforming ◽  
Temperature Range ◽  
Thermal Pyrolysis ◽  
First Order Kinetics ◽  
Initial Stage ◽  
Conversion Of Methane ◽  
Exponential Factors ◽  
Kinetics Of

Abstract A detailed kinetic modeling of the noncatalytic processes of thermal pyrolysis and steam and carbon dioxide reforming of methane revealed almost completely identical kinetics of the methane conversion in these processes. This suggests that, in the temperature range 1400–1800 K, the initial stage of conversion of methane in all these processes is its thermal pyrolysis. The modeling results agree well with the experimental data on methane pyrolysis. For the temperature range examined, the Arrhenius expressions (pre-exponential factors and activation energy) were obtained in the first-order kinetics approximation for the rate of methane conversion in the processes studied. The expressions derived may be useful for making preliminary estimates and carrying out engineering calculations.

scholarly journals Further investigations on the kinetics of gaseous oxidation reactions

1930 ◽  
Vol 129 (810) ◽  
pp. 284-299 ◽  
Keyword(s):  
Rate Of Change ◽  
Chain Mechanism ◽  
Oxidation Reactions ◽  
Chain Reactions ◽  
Oxidation Of Methane ◽  
Simple Order ◽  
Oxidation Of Hydrocarbons ◽  
Rate Of Reaction ◽  
A Chain ◽  
Kinetics Of

Investigation of the kinetics of the oxidation of ethylene and of benzene showed that these reactions are peculiar in the following respects. First, the relation between the rate of reaction and concentration is such that the reactions possess no simple “order,” though the nearest integral value for the order is about the third of fourth. The rate increases very rapidly with increasing hydrocarbon concentration, but is relatively little influenced by oxygen; under some conditions oxygen may have a retarding influence. Secondly, the reactions can be slowed down by increasing the surface exposed to the gases. This indicates that the oxidation occurs by a chain mechanism. Thirdly, the rate of change of pressure accompanying the oxidation only attains its full value after an induction period, during which evidently intermediate products are accumulating. Accepting the fact that the oxidations are probably chain reactions, the relation between rate and concentration shown that the chains are much more easily propagated when the intermediate active molecules encounter more hydrocarbon than when they encounter oxygen. Following the view of Egerton, and consistently with previous work on the combination of hydrogen and oxygen, the working hypothesis adopted is that some intermediate peroxidised substance is responsible for the propagation of the chains. This being so, the question arises whether the peculiarities found in the oxidation of hydrocarbons will also be found with substances already containing oxygen. To investigate, therefore, the influence of chemical configuration on the mechanism of oxidation reactions the following series of compounds has been studied CH 4 CH 3 OH HCHO which represent the stages through which Bone and others have shown the oxidation of methane to occur.

scholarly journals Исследование с помощью молекулярной динамики образования димеров на поверхности (001) GaAs при низких температурах

2021 ◽  
Vol 55 (2) ◽  
pp. 134
Author(s):  
Н.Д. Прасолов ◽  
А.А. Гуткин ◽  
П.Н. Брунков
Keyword(s):  
Potential Energy ◽  
Thermal Activation ◽  
Average Rate ◽  
Temperature Reconstruction ◽  
Temperature Range ◽  
Quantum Mechanical Theory ◽  
Bond Order Potential ◽  
A Chain ◽  
Kinetics Of ◽  
Dynamics Method

The simulation of dimers formation during the low-temperature reconstruction of GaAs (001) surface terminated with Ga or As atoms was performed by the molecular dynamics method using the analytical Bond-Order Potential based on quantum mechanical theory incorporating both σ- and π- bonds between atoms. A decrease in values of potential energy of the atoms during formation of isolated surface dimer have been determined. It has been found that potential energy of an atom in As-dimer is several tenths of an eV lower than in Ga-dimer. Kinetics of the initial stages of Ga-dimers formation in the temperature range of 25 - 40 K was studied. It was found that the characteristic thermal activation energy of single isolated Ga-dimers formation is ~ 29 meV, which is lower than the same value for As-dimers (~ 38 meV). Time constants characterizing the average rate of transformation of one dimer into a chain of two dimers at temperature range of 28 - 37 K were estimated. Inverse values of these parameters for paired Ga- and As-dimers are in the ranges of 10^11 – 10^12 s^-1 and 10^9 – 10^10 s^-1, respectively, while corresponding parameters for the formation of single dimers are in the ranges of 4·10^6 – 10^8 s^-1 and 1.4·10^6 – 7.4·10^7 s^-1.

Initial stage of thermal-oxidation reactions on Cl-adsorbed Si surfaces

1991 ◽  
Vol 256 (3) ◽  
pp. A542
Author(s):  
Nahomi Aoto ◽  
Hirohito Watanabe ◽  
Takamaro Kikkawa
Keyword(s):  
Thermal Oxidation ◽  
Oxidation Reactions ◽  
Initial Stage

Initial stage of thermal-oxidation reactions on Cl-adsorbed Si surfaces

1991 ◽  
Vol 256 (3) ◽  
pp. 361-369 ◽  
Author(s):  
Nahomi Aoto ◽  
Hirohito Watanabe ◽  
Takamaro Kikkawa
Keyword(s):  
Thermal Oxidation ◽  
Oxidation Reactions ◽  
Initial Stage

scholarly journals Kinetics of integrated liquid phase sintering of glass-alumina composite: Activated pores evolution

2011 ◽  
Vol 43 (3) ◽  
pp. 327-333
Author(s):  
Cheng-Long Yu ◽  
Xin Hao ◽  
Hong-Tao Jiang ◽  
Li-Li Wang ◽  
Xiu-Feng Wang
Keyword(s):  
Liquid Phase ◽  
Field Emission ◽  
Final Stage ◽  
Glass Matrix ◽  
Liquid Phase Sintering ◽  
Kinetics Equation ◽  
Scanning Microscope ◽  
Initial Stage ◽  
Alumina Composite ◽  
Kinetics Of

Activated pores in the glass-alumina composite during isothermal sintering at 710?C by colloidal processing were extracted by the threshold conversion of the micrograph obtained with a field emission scanning microscope. The relative ratio of the activated pores in the final stage of sintering to that in the initial stage of sintering was calculated. The kinetics equation of the evolution of the activated pores during isothermal sintering was established. The pores evolution confirms the viscous flow of the glass matrix, indicating the validity of the predominant liquid-phase sintering of the composite.

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