THE KINETICS OF THE REACTION OF ACTIVE NITROGEN WITH ETHYLENE

1962 ◽  
Vol 40 (4) ◽  
pp. 686-691 ◽  
Author(s):  
E. M. Levy ◽  
C. A. Winkler
Keyword(s):  
Nitric Oxide ◽  
Activation Energy ◽  
Low Temperature ◽  
Copper Oxide ◽  
Cobalt Catalyst ◽  
Cobalt Catalysts ◽  
Active Nitrogen ◽  
Temperature Range ◽  
P Factor ◽  
Kinetics Of

A comparison has been made of five methods for terminating the reaction of active nitrogen with ethylene in the temperature range 295° to 673° K. These were based on deactivating the active nitrogen by low-temperature trapping, by addition of nitric oxide, and by passing it over copper oxide or cobalt catalysts. With the nitric oxide and cobalt catalyst techniques, which appeared to be the most reliable of those used, an activation energy of 400 ± 200 cal/mole, with a P factor of about 10−5, have been determined for the reaction.

THE KINETICS OF THE THERMAL DECOMPOSITIONS OF THE LOWER PARAFFINS: V. THE NITRIC OXIDE INHIBITED DECOMPOSITION OF n-BUTANE

1940 ◽  
Vol 18b (1) ◽  
pp. 1-11 ◽  
Author(s):  
E. W. R. Steacie ◽  
H. O. Folkins
Keyword(s):  
Nitric Oxide ◽  
Thermal Decomposition ◽  
Free Radical ◽  
High Pressures ◽  
Free Radical Processes ◽  
Temperature Range ◽  
Radical Recombination ◽  
Radical Processes ◽  
Kinetics Of ◽  
Good Agreement

A detailed investigation of the inhibition by nitric oxide of the thermal decomposition of n-butane has been carried out over the temperature range 500° to 550 °C.In all cases it was found that inhibition decreased with increasing butane concentration. This suggests that radical recombination occurs in the normal decomposition by ternary collisions with butane molecules acting as third bodies.The activation energies of the normal and inhibited reactions have been determined. For high pressures the two values are in good agreement, viz., 58,200 and 57,200 cal. per mole respectively. The products of the inhibited reaction were also found to be the same as those of the normal reaction.It is concluded that free radical processes predominate, involving comparatively short chains.

THE KINETICS OF CUPRENE GROWTH

1950 ◽  
Vol 28b (7) ◽  
pp. 358-372
Author(s):  
Cyrias Ouellet ◽  
Adrien E. Léger
Keyword(s):  
Nitric Oxide ◽  
Activation Energy ◽  
Carbon Monoxide ◽  
Apparent Activation Energy ◽  
Copper Catalyst ◽  
Maximum Velocity ◽  
Static System ◽  
Reaction Velocity ◽  
First Order ◽  
Kinetics Of

The kinetics of the polymerization of acetylene to cuprene on a copper catalyst between 200° and 300 °C. have been studied manometrically in a static system. The maximum velocity of the autocatalytic reaction shows a first-order dependence upon acetylene pressure. The reaction is retarded in the presence of small amounts of oxygen but accelerated by preoxidation of the catalyst. The apparent activation energy, of about 10 kcal. per mole for cuprene growth between 210° and 280 °C., changes to about 40 kcal. per mole above 280 °C. at which temperature a second reaction seems to set in. Hydrogen, carbon monoxide, or nitric oxide has no effect on the reaction velocity. Series of five successive seedings have been obtained with cuprene originally grown on cuprite, and show an effect of aging of the cuprene.

Diffusion Mechanisms in Nanocrystalline and Nanolaminated Au-Cu

2007 ◽  
Vol 266 ◽  
pp. 13-28 ◽  
Author(s):  
Alan F. Jankowski
Keyword(s):  
Low Temperature ◽  
Grain Boundary ◽  
Grain Growth ◽  
Boundary Diffusion ◽  
Bulk Diffusion ◽  
Grain Boundary Diffusion ◽  
Dominant Mechanism ◽  
Temperature Range ◽  
Diffusion Mechanisms ◽  
Kinetics Of

Thermal anneal treatments are used to identify the temperature range of the two dominant diffusion mechanisms – bulk and grain boundary. To assess the transition between mechanisms, the low temperature range for bulk diffusion is established utilizing the decay of static concentration waves in composition-modulated nanolaminates. These multilayered structures are synthesized using vapor deposition methods as thermal evaporation and magnetron sputtering. However, at low temperature the kinetics of grain-boundary diffusion are much faster than bulk diffusion. The synthesis of Au-Cu alloys (0-20 wt.% Cu) with grain sizes as small as 5 nm is accomplished using pulsed electro-deposition. Since the nanocrystalline grain structure is thermally unstable, these structures are ideal for measuring the kinetics of grain boundary diffusion as measured by coarsening of grain size with low temperature anneal treatments. A transition in the dominant mechanism for grain growth from grain boundary to bulk diffusion is found with an increase in temperature. The activation energy for bulk diffusion is found to be 1.8 eV·atom-1 whereas that for grain growth at low temperatures is only 0.2 eV·atom-1. The temperature for transitioning from the dominant mechanism of grain boundary to bulk diffusion is found to be 57% of the alloy melt temperature and is dependent on composition.

Diffusion kinetics of gold in TiO2 nanotube arrays for formation of Au@TiO2 nanotube arrays

RSC Advances ◽  
2016 ◽  
Vol 6 (54) ◽  
pp. 48580-48588 ◽  
Author(s):  
Wanggang Zhang ◽  
Yiming Liu ◽  
Diaoyu Zhou ◽  
Jing Wen ◽  
Liuwei Zheng ◽  
...  
Keyword(s):  
Activation Energy ◽  
Tio2 Nanotube Arrays ◽  
Tio2 Nanotube ◽  
Nanotube Arrays ◽  
Diffusion Kinetics ◽  
Temperature Range ◽  
Heating Treatment ◽  
Kinetics Of

Heating treatment leads to the diffusion of Au into TiO2 nanotube arrays and the formation of Au nanocrystals. The activation energy for the Au diffusion on the surface of the TiO2 nanotubes in the temperature range of 400 to 500 °C is 67.2 kJ mol−1.

scholarly journals Microtubule assembly kinetics. Changes with solution conditions

1987 ◽  
Vol 247 (3) ◽  
pp. 505-511 ◽  
Author(s):  
J S Barton ◽  
D L Vandivort ◽  
D H Heacock ◽  
J A Coffman ◽  
K A Trygg
Keyword(s):  
Activation Energy ◽  
Ionic Strength ◽  
Low Temperature ◽  
Number Concentration ◽  
High Ionic Strength ◽  
Microtubule Assembly ◽  
Microtubule Protein ◽  
Assembly Kinetics ◽  
Low Ionic Strength ◽  
Kinetics Of

The assembly kinetics of microtubule protein are altered by ionic strength, temperature and Mg2+, but not by pH. High ionic strength (I0.2), low temperature (T less than 30 degrees C) and elevated Mg2+ (greater than or equal to 1.2 mM) induce a transition from biphasic to monophasic kinetics. Comparison of the activation energy obtained for the fast biphasic step at low ionic strength (I0.069) shows excellent agreement with the values obtained at high ionic strength, low temperature and elevated Mg2+. From this observation it can be implied that the tubulin-containing reactant of the fast biphasic event is also the species that elongates microtubules during monophasic assembly. Second-order rate constants for biphasic assembly are 3.82(+/- 0.72) x 10(7) M-1.s-1 and 5.19(+/- 1.25) x 10(6) M-1.s-1, and for monophasic assembly the rate constant is 2.12(+/- 0.56) x 10(7) M-1.s-1. The microtubule number concentration is constant during elongation of microtubules for biphasic and monophasic assembly.

scholarly journals Pyrolytic characteristics and kinetics of Guanzhong wheat straw and its components for high-value products

BioResources ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. 1958-1979
Author(s):  
Bingtao Hu ◽  
Zhaolin Gu ◽  
Junwei Su ◽  
Zhijian Li
Keyword(s):  
Activation Energy ◽  
Apparent Activation Energy ◽  
Wheat Straw ◽  
Pyrolysis Products ◽  
Transportation Fuels ◽  
Temperature Range ◽  
Model Free ◽  
System A ◽  
Gas Products ◽  
Kinetics Of

Wheat straw produced annually in the Shaanxi Guanzhong region is a potential biomass feedstock for the production of transportation fuels and specialized chemicals through combustion, pyrolysis, or gasification. In this work, the pyrolytic characteristics, evolved gas products, and kinetics of Guanzhong wheat straw and its components were first investigated with a thermogravimetry-Fourier infrared spectroscopy (TG-FTIR) system. A comparative kinetic study was conducted using different model-free methods of Flynn-Wall-Ozawa (FWO), Kissinger-Akahira-Sunose (KAS), Kissinger, and the Coats-Redfern methods. The main pyrolysis products identified by FTIR include H2O, CH4, CO2, and CO as well as aromatics, acids, ketones, and aldehydes. Kinetic results showed that the pyrolytic apparent activation energy of the straw is approximately 200 kJ/mol obtained via FWO and KAS methods at the conversion range of 0.4 to 0.75, which was 30 kJ/mol higher than the value 171.1 kJ/mol obtained by the Kissinger method. The apparent activation energy of cellulose in its main pyrolysis region is 135.5 kJ/mol and is about three times larger than that of hemicellulose (49.5 kJ/mol). The apparent activation energy of lignin at the temperature range of 45 to 116 °C was 34.5 kJ/mol, while that value at the temperature range of 120 to 252 °C was 6.64 kJ/mol.

Kinetics of the Reaction between Silver and Nitric Acid

1962 ◽  
Vol 15 (2) ◽  
pp. 181 ◽  
Author(s):  
JJ Batten
Keyword(s):  
Activation Energy ◽  
Nitric Acid ◽  
Induction Period ◽  
Acid Concentration ◽  
Maximum Rate ◽  
Kcal Mole ◽  
Temperature Range ◽  
Induction Rate ◽  
Rate Of Dissolution ◽  
Kinetics Of

The rate of dissolution of silver gauze in nitric acid at various concentrations and temperatures was measured in a static system. The solution process was measured by the weight of silver dissolved in various time intervals. In general, induction periods were observed, but after this period the dissolution proceeded with an appreciable velocity. To examine the influence of acid concentration and temperature on the kinetics of the reaction, the duration of the induction period, the rate of dissolution during this period, and the subsequent maximum rate were taken as kinetic parameters of the reaction. The induction rate was found to be highly dependent on the initial acid concentration (approx. seventh power), whereas over most of the concentration range accessible to study, the maximum rate was proportional to the square of the concentration. It was also observed that increase in temperature sharply increases the induction rate, but has little effect upon the subsequent maximum rate over most of the temperature range studied. The activation energy of the induction rate was greater than 20 kcal/mole, whereas that of the maximum rate was about 4 kcal/mole over most of the temperature range studied. This difference in the activation energy during and after the induction period is explained by a shift in the mechanism controlling the rate of the process from a chemical reaction at the surface to a diffusion process.

Formation and Effects of Secondary Defects in Ion implanted Silicon

1980 ◽  
Vol 2 ◽  
Author(s):  
Jack Washburn
Keyword(s):  
Activation Energy ◽  
Electron Microscope ◽  
Low Temperature ◽  
Ion Implantation ◽  
Room Temperature ◽  
Laser Annealing ◽  
Subsequent Annealing ◽  
Interface Migration ◽  
Kinetics Of ◽  
Ion Implanted

ABSTRACTThe clustering of isolated interstitial silicon, implanted atoms, and vacant lattice sites produced by low temperature and room temperature ion implantation during subsequent annealing is reviewed. An electron microscope method for studying the kinetics of the amorphous to crystalline transformation in silicon is described. The technique is applied to measurement of the activation energy for interface migration and the formation of microtwins for different growth directions. A very brief review of the effects of laser annealing after ion implantation is included.

Research on Kinetics of Hydrolysis Preparation of Micro-Molecular Dextran

2013 ◽  
Vol 748 ◽  
pp. 295-298
Author(s):  
Shu Qiong Liao ◽  
Xiao Yu Peng ◽  
Xue Wang Zhang ◽  
Ke Lin Huang ◽  
Ben Wang ◽  
...  
Keyword(s):  
Activation Energy ◽  
Molecular Weight ◽  
Kinetics Equation ◽  
Temperature Range ◽  
Kinetics Of Hydrolysis ◽  
Kinetics Of ◽  
Hydrolysis Of

Micro-molecular dextran was prepared in sub-critical water and sub-critical Water/CO2by hydrolysis of dextran20. The obtained products were mainly characterized by GPC. The kinetics of hydrolysis of dextran20 has been studied in the temperature range of 423.15K-463.15K. It was found that the level of dextran20 hydrolysis in sub-critical water and sub-critical water/CO2was first level kinetics equation. The activation energy was also calculated. The results demonstrated that the molecular weight of micro-molecular dextran could be controlled.

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