scholarly journals THE REACTION OF NITROGEN ATOMS WITH METHANE AND ETHANE

1951 ◽  
Vol 29 (11) ◽  
pp. 1010-1021 ◽  
Author(s):  
H. Blades ◽  
C. A. Winkler
Keyword(s):  
Activation Energy ◽  
Nitrogen Atom ◽  
High Temperatures ◽  
Hydrogen Cyanide ◽  
Active Species ◽  
Second Order ◽  
Steric Factor ◽  
Atomic Nitrogen ◽  
Atom Concentration ◽  
Nitrogen Stream

Methane reacted with nitrogen atoms at temperatures above 300°C. to produce hydrogen cyanide. An activation energy of 11 kcal. and a steric factor of 5 × 10−3 were obtained. The reaction of ethane with nitrogen atoms was studied up to 295°C., with hydrogen cyanide the only product found in measurable amounts. At high temperatures, nitrogen atom consumption was complete in excess ethane, and the hydrogen cyanide production under these conditions, compared with the atom concentration determined by a Wrede gauge, indicated the active species in the nitrogen stream to be only atomic nitrogen. The ethane – nitrogen atom reaction was second order, with an activation energy of 7 ± 1 kcal. and a steric factor between 10−1 and 10−3.

THE REACTION OF ACTIVE NITROGEN WITH PROPANE

1954 ◽  
Vol 32 (4) ◽  
pp. 351-355 ◽  
Author(s):  
M. Onyszchuk ◽  
L. Breitman ◽  
C. A. Winkler
Keyword(s):  
Activation Energy ◽  
Flow Rate ◽  
Rate Constants ◽  
Hydrogen Cyanide ◽  
Main Product ◽  
Second Order ◽  
Steric Factor ◽  
Active Nitrogen ◽  
Flow Rates ◽  
Order Rate

The reaction of nitrogen atoms with propane has been found to produce hydrogen cyanide as the main product, together with smaller amounts of acetylene, ethylene, and ethane, which were recovered at all propane flow rates. Complete consumption of nitrogen atoms was not attained at any propane flow rate used at 63 °C, but was attained at 250 °C for ratios of propane to nitrogen atoms greater than 1.3. An activation energy of 5.6 ± 0.6 kcal. and a steric factor between 10−2 and 10−3 was estimated from second order rate constants.

THE REACTION OF ACTIVE NITROGEN WITH PROPYLENE

1952 ◽  
Vol 30 (12) ◽  
pp. 915-921 ◽  
Author(s):  
G. S. Trick ◽  
C. A. Winkler
Keyword(s):  
Double Bond ◽  
Nitrogen Atom ◽  
Hydrogen Cyanide ◽  
Atomic Hydrogen ◽  
Atomic Nitrogen ◽  
Active Nitrogen

The reaction of nitrogen atoms with propylene has been found to produce hydrogen cyanide and ethylene as the main products, together with smaller amounts of ethane and propane and traces of acetylene and of a C4 fraction. With excess propylene, the nitrogen atoms were completely consumed and for the reaction at 242 °C., 0.77 mole of ethylene was produced for each mole of excess propylene added. For reactions at lower temperatures, less ethylene was produced. The proposed mechanism involves formation of a complex between the nitrogen atom and the double bond of propylene, followed by decomposition to ethylene, hydrogen cyanide, and atomic hydrogen. The ethylene would then react with atomic nitrogen in a similar manner.

THE REACTIONS OF ACTIVE NITROGEN WITH THE BUTANES

1954 ◽  
Vol 32 (7) ◽  
pp. 718-724 ◽  
Author(s):  
R. A. Back ◽  
C. A. Winkler
Keyword(s):  
Nitrogen Atom ◽  
Rate Constants ◽  
Hydrogen Cyanide ◽  
Main Product ◽  
Activation Energies ◽  
Reactive Species ◽  
Atomic Nitrogen ◽  
Initial Attack ◽  
Active Nitrogen ◽  
Rate Controlling Step

The main product of the reactions of active nitrogen with n- and iso-butanes at 75 °C. and 250 °C. was hydrogen cyanide. Small amounts of C2 hydrocarbons, mainly ethylene and acetylene, were produced in both reactions. Second order rate constants were calculated on the assumption that the reactive species in active nitrogen is atomic nitrogen, and that the initial attack of a nitrogen atom is the rate-controlling step. The activation energies were then estimated to be 3.6 kcal. and 3.1 kcal. and the probability factors 4.5 × 10−4 and 4.4 × 10−4, for the n-butane and isobutane reactions respectively.

THE REACTION OF NITROGEN ATOMS WITH ETHYLENE

1949 ◽  
Vol 27b (8) ◽  
pp. 721-731
Author(s):  
C. A. Winkler ◽  
J. H. Greenblatt
Keyword(s):  
Activation Energy ◽  
Double Bond ◽  
Hydrogen Cyanide ◽  
Steric Factor ◽  
Methyl Radical

Reaction of nitrogen atoms with ethylene has been found to produce hydrogen cyanide, ethane, and a polymerizable material. The yield of hydrogen cyanide was approximately 70% of the ethylene consumed by nitrogen atoms, while the amount of polymerizable material averaged about 16% by weight of the hydrogen cyanide produced. The yield of ethane increased as the excess of ethylene over nitrogen atoms was increased. The reaction was found to proceed by "clean-up of nitrogen atoms. An activation energy of 6.9 kcal. was calculated from collision yields, a steric factor of 0.1 being assumed. A mechanism for the reaction has been proposed, involving rupture of the ethylene double bond with formation of hydrogen cyanide and a methyl radical, the methyl radical then reacting further with nitrogen atoms.

THE REACTION OF DEUTERIUM ATOMS WITH METHANE AT HIGH TEMPERATURES

1937 ◽  
Vol 15b (6) ◽  
pp. 264-273 ◽  
Author(s):  
E. W. R. Steacie
Keyword(s):  
Activation Energy ◽  
High Temperatures ◽  
Atom Concentration ◽  
Good Agreement

Using the Wood-Bonhoeffer method, an investigation has been made of the reaction of deuterium atoms with methane at temperatures up to 500 °C. Owing to the difficulties involved in poisoning the walls to prevent atom recombination at high temperatures, the atom concentration was very variable. The results are therefore only approximate, but they serve to establish definitely the presence of a reaction at the temperatures under investigation, and enable the estimation of the activation energy of the reaction[Formula: see text]viz., 12.9 ± 2 Kcal. This is in good agreement with values obtained in other investigations.

High Temperature n- and p-type Doped Microcrystalline Silicon Layers Grown by VHF PECVD Layer-by-Layer Deposition

2003 ◽  
Vol 762 ◽  
Author(s):  
A. Gordijn ◽  
J.K. Rath ◽  
R.E.I. Schropp
Keyword(s):  
Activation Energy ◽  
High Temperature ◽  
High Temperatures ◽  
Continuous Wave ◽  
Hydrogen Plasma ◽  
Silicon Layer ◽  
Dark Conductivity ◽  
High Deposition Rate ◽  
Layer By Layer ◽  
Microcrystalline Silicon

AbstractDue to the high temperatures used for high deposition rate microcrystalline (μc-Si:H) and polycrystalline silicon, there is a need for compact and temperature-stable doped layers. In this study we report on films grown by the layer-by-layer method (LbL) using VHF PECVD. Growth of an amorphous silicon layer is alternated by a hydrogen plasma treatment. In LbL, the surface reactions are separated time-wise from the nucleation in the bulk. We observed that it is possible to incorporate dopant atoms in the layer, without disturbing the nucleation. Even at high substrate temperatures (up to 400°C) doped layers can be made microcrystalline. At these temperatures, in the continuous wave case, crystallinity is hindered, which is generally attributed to the out-diffusion of hydrogen from the surface and the presence of impurities (dopants).We observe that the parameter window for the treatment time for p-layers is smaller compared to n-layers. Moreover we observe that for high temperatures, the nucleation of p-layers is more adversely affected than for n-layers. Thin, doped layers have been structurally, optically and electrically characterized. The best n-layer made at 400°C, with a thickness of only 31 nm, had an activation energy of 0.056 eV and a dark conductivity of 2.7 S/cm, while the best p-layer made at 350°C, with a thickness of 29 nm, had an activation energy of 0.11 V and a dark conductivity of 0.1 S/cm. The suitability of these high temperature n-layers has been demonstrated in an n-i-p microcrystalline silicon solar cell with an unoptimized μc-Si:H i-layer deposited at 250°C and without buffer. The Voc of the cell is 0.48 V and the fill factor is 70 %.

Doping Effect in Nickel Oxide

2009 ◽  
Vol 289-292 ◽  
pp. 775-782 ◽  
Author(s):  
Zbigniew Jurasz ◽  
Krzysztof Adamaszek ◽  
Romuald Janik ◽  
Zbigniew Grzesik ◽  
Stanisław Mrowec
Keyword(s):  
Activation Energy ◽  
Nickel Oxide ◽  
High Temperatures ◽  
Oxygen Pressure ◽  
Pressure Dependence ◽  
Oxidation Rate ◽  
Doping Effect ◽  
Self Diffusion ◽  
Electron Holes ◽  
Influence Of Impurities

Detailed investigations of nonstoichiometry as well as chemical and self-diffusion in nickel oxide have shown that doubly ionised cation vacancies and electron holes are the predominant defects in this material. The present work is an attempt to demonstrate that aliovalent impurities (Cr, Al, Na and Li) may considerably influence the concentration of these defects and, consequently, the oxidation rate of nickel at high temperatures. It has been shown that small amounts of tri-valent impurities (Cr, Al) bring about an increase of the oxidation rate, while mono-valent ones (Li, Na) decrease the rate of oxidation. These phenomena may satisfactorily be explained in terms of a doping effect. All experiments have been carried out as a function of temperature (1373-1673 K) and oxygen pressure (1-105 Pa) and consequently, it was possible to determine the influence of impurities not only on the oxidation rate but also on the activation energy of reaction and its pressure dependence. The results of these investigations could again be elucidated in terms of doping effect.

scholarly journals Utilization of Second Order Slip, Activation Energy and Viscous Dissipation Consequences in Thermally Developed Flow of Third Grade Nanofluid with Gyrotactic Microorganisms

Symmetry ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 309 ◽  
Author(s):  
Zahra Abdelmalek ◽  
Sami Ullah Khan ◽  
Hassan Waqas ◽  
Hossam A. Nabwey ◽  
Iskander Tlili
Keyword(s):  
Activation Energy ◽  
Viscous Dissipation ◽  
Microbial Fuel Cells ◽  
Liquid Metals ◽  
Second Order ◽  
Transformer Oil ◽  
Third Grade ◽  
Physical Parameters ◽  
Gyrotactic Microorganisms ◽  
Motion Features

In recent decades, an interest has been developed towards the thermal consequences of nanofluid because of utilization of nano-materials to improve the thermal conductivity of traditional liquid and subsequently enhance the heat transportation phenomenon. Following this primarily concept, this current work investigates the thermal developed flow of third-grade nanofluid configured by a stretched surface with additional features of activation energy, viscous dissipation and second-order slip. Buongiorno’s nanofluid model is used to explore the thermophoresis and Brownian motion features based on symmetry fundamentals. It is further assumed that the nanoparticles contain gyrotactic microorganisms, which are associated with the most fascination bioconvection phenomenon. The flow problem owing to the partial differential equations is renovated into dimensional form, which is numerically simulated with the help of bvp4c, by using MATLAB software. The aspects of various physical parameters associated to the current analysis are graphically examined against nanoparticles’ velocity, temperature, concentration and gyrotactic microorganisms’ density distributions. Further, the objective of local Nusselt number, local Sherwood number and motile density number are achieved numerically with variation of various parameters. The results presented here may find valuable engineering applications, like cooling liquid metals, solar systems, power production, solar energy, thermal extrusion systems cooling of machine equipment, transformer oil and microelectronics. Further, flow of nanoparticles containing gyrotactic microorganisms has interesting applications in microbial fuel cells, microfluidic devices, bio-technology and enzyme biosensors.

Aromatic oxidation by cobaltic acetate in acetic acid

1969 ◽  
Vol 47 (3) ◽  
pp. 387-392 ◽  
Author(s):  
Koichiro Sakota ◽  
Yoshio Kamiya ◽  
Nobuto Ohta
Keyword(s):  
Activation Energy ◽  
Electron Transfer ◽  
Acetic Acid ◽  
Bond Energy ◽  
Hydrogen Abstraction ◽  
Steric Factor ◽  
Benzyl Acetate ◽  
Kcal Mole ◽  
First Order ◽  
Reversible Electron Transfer

A detailed kinetic study of oxidation of toluene and its derivatives by cobaltic acetate in 95 vol% acetic acid is reported. The reaction was found to be profoundly affected by a steric factor and rather insensitive to the C—H bond energy. The order of reactivities of various alkylbenzenes is quite reversal to that of hydrogen abstraction reactions. The reaction was of first-order with respect to toluene, of second-order with respect to cobaltic ion and of inverse first-order with respect to cobaltous ion. The oxidation by cobaltic ion seems to proceed via an initial reversible electron transfer from toluene to cobaltic ion, yielding [Formula: see text] which is oxidized into benzyl acetate by another cobaltic ion. The apparent activation energy for toluene was found to be 25.3 kcal mole−1, and the same activation energy was found for ethylbenzene, cumene, diphenylmethane, and triphenylmethane.

THE REACTION OF HYDROGEN AND DEUTERIUM ATOMS WITH PROPANE

1939 ◽  
Vol 17b (12) ◽  
pp. 371-384 ◽  
Author(s):  
E. W. R. Steacie ◽  
N. A. D. Parlee
Keyword(s):  
Activation Energy ◽  
High Temperatures ◽  
Low Temperatures ◽  
Hydrogen Atoms ◽  
Temperature Range ◽  
Secondary Reactions

The reaction of hydrogen atoms with propane has been investigated over the temperature range 30° to 250 °C. by the Wood-Bonhoeffer method. The products are solely methane at low temperatures, and methane, ethane, and ethylene at higher temperatures.It is concluded that the results can be explained only by the assumption that the reaction[Formula: see text]is of importance. The bearing of this on the Rice-Herzfeld mechanisms is discussed. The activation energy of the reaction is 10 ± 2 Kcal.The main steps in the postulated mechanism are:Primary Reaction[Formula: see text]Secondary Reactions at Low Temperatures[Formula: see text]Additional Secondary Reactions at High Temperatures[Formula: see text]The reaction of deuterium atoms with propane was also investigated. It was found that the methane and ethane produced were highly deuterized, while the propane was not appreciably exchanged.

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