Kinetic study of the conversion of presolvated to solvated silver atoms in polycrystalline ice: Activation energy of water molecule rotation withD‐defect annihilation

1981 ◽  
Vol 75 (12) ◽  
pp. 5968-5969
Author(s):  
A. S. W. Li ◽  
Larry Kevan
Keyword(s):  
Activation Energy ◽  
Water Molecule ◽  
Kinetic Study ◽  
Polycrystalline Ice ◽  
Silver Atoms

A kinetic study of mechanochemical halogen bond formation by in situ31P solid-state NMR spectroscopy

2017 ◽  
Vol 53 (71) ◽  
pp. 9930-9933 ◽  
Author(s):  
Yijue Xu ◽  
Lysiane Champion ◽  
Bulat Gabidullin ◽  
David L. Bryce
Keyword(s):  
Activation Energy ◽  
Solid State ◽  
Nmr Spectroscopy ◽  
Kinetic Study ◽  
Solid State Nmr ◽  
Halogen Bond ◽  
Bond Formation ◽  
Nmr Studies ◽  
Solid State Nmr Spectroscopy

In situ 31P solid-state NMR studies of mechanochemical halogen bond formation provide insights into the cocrystallisation process and an estimate of the activation energy.

scholarly journals Non-isothermal Kinetic Study ofp-Cresol-Dithiooxamide-Formaldehyde Terpolymer

2010 ◽  
Vol 7 (4) ◽  
pp. 1380-1390 ◽  
Author(s):  
W. B. Gurnule ◽  
S. S. Katkamwar
Keyword(s):  
Activation Energy ◽  
Thermal Stability ◽  
Thermal Degradation ◽  
Kinetic Study ◽  
Elemental Analysis ◽  
Frequency Factor ◽  
Entropy Change ◽  
H Nmr ◽  
Uv Visible ◽  
Isothermal Kinetic

Terpolymer (p-CDF) has been prepared by using the monomerp-cresol, dithiooxanude and formaldehyde in 1:1:2 molar proportions. The structure ofp-CDF terpolymer has been elucidated on the basis of elemental analysis and various physicochemical technique like UV-visible, FTIR,1H NMR and TG analysis. Detailed thermal degradation curve is discussed which shows four steps decomposition. The activation energy (Ea) and thermal stability calculated by using the Sharp Wentworth, Frceman-Carroll methods. Thermodynamics parameters such as entropy change (ΔS), apparent entropy change (S*) and frequency factor (z) have also been evaluated on the basis of the data of Freeman-Carroll method. The order of reaction (n) is found to be 1.05.

scholarly journals Reduction behavior of Tin-containing phase in Tin-bearing iron concentrates under CO-CO2 mixed gases

2019 ◽  
Vol 55 (2) ◽  
pp. 177-185 ◽  
Author(s):  
Y. Yu ◽  
H.-J. Li ◽  
L. Li
Keyword(s):  
Activation Energy ◽  
Chemical Analysis ◽  
Kinetic Study ◽  
Reduction Behavior ◽  
No Formation ◽  
Roasting Temperature ◽  
The One ◽  
Mixed Gases

The main purpose of this study was to ascertain the reduction behavior of tin phase (SnO2) in tin-bearing iron concentrates at the respective temperature of 1273 and 1373 K in diverse CO-CO2 mixed gases using chemical analysis, XRD, and SEMEDS analysis. The results show that the reduction behavior of SnO2 depends on the roasting temperature and CO content. At 1273 K, the SnO2 will be reduced to Sn (l) with the CO content being higher than 17.26 vol%, and there is no formation of SnO(s). With the temperature increased to 1373 K, the SnO2 is reduced stepwise in the order to form SnO2 ? SnO (l) ? Sn(l) with CO content over 15.75 vol%. The kinetic study shows that activation energy of the reaction SnO2(s)+CO(g)=Sn(l)+ CO2(g) is 144.75 kJ/mol at 1073-1223 K, being far lower than the one in the reduction of SnO2(s) into SnO(g) at 1273-1323 K, which leads to a conclusion that the tin in tin-bearing iron concentrates could be removed effectively after the Sn(l) sulfurated into SnS at relatively lower temperatures (1073-1223 K) using the sulfidation roasting method.

Kinetic study and effect of water on methane oxidation to methanol over copper-exchanged mordenite

2020 ◽  
Vol 10 (2) ◽  
pp. 382-390 ◽  
Author(s):  
Vitaly L. Sushkevich ◽  
Jeroen A. van Bokhoven
Keyword(s):  
Carbon Monoxide ◽  
Water Molecule ◽  
Kinetic Study ◽  
Methane Oxidation ◽  
Active Species ◽  
Effect Of Water ◽  
Primary Products

Kinetic experiments show that both methoxy species and carbon monoxide are primary products. Adsorption of one water molecule reversibly blocks at least two copper atoms in active species.

scholarly journals A Deformation Mechanism Map of Ice

1978 ◽  
Vol 21 (85) ◽  
pp. 419-427 ◽  
Author(s):  
H. Shōji ◽  
A. Higashi
Keyword(s):  
Activation Energy ◽  
Deformation Mechanism ◽  
Deformation Rate ◽  
Crack Formation ◽  
Dislocation Creep ◽  
Stress Dependence ◽  
Dislocation Glide ◽  
Fracture Region ◽  
Polycrystalline Ice ◽  
Rapid Deformation

AbstractA deformation mechanism map for pure polycrystalline ice of 2 mm grain diameter is constructed, New sub-regions in the dislocation glide region are proposed: dislocation glide with crack formation, dislocation creep, and fracture at high stresses above about 1 MPa. The boundary between the dislocation creep and DGC regions is determined by the onset of cleavage cracks due to piled-up dislocations near grain boundaries. The fracture region is that area of the map where fracture occurs readily when the ice is subjected to a rapid deformation rate exceeding 10-3 s-1. Experimental results of the stress dependence of the compressive deformation rate of polycrystalline ice are compared with the map. The effect of changes in the creep activation energy near the melting point is discussed together with those of other factors.

Kinetic Study of the Epimerization of 1,1,1-Trichloro-2-hydroxy-3-methyl-4-hexanone

1973 ◽  
Vol 51 (19) ◽  
pp. 3182-3186 ◽  
Author(s):  
Eberhard Kiehlmann ◽  
Fred Masaro ◽  
Frederick J. Slawson
Keyword(s):  
Activation Energy ◽  
Acetic Acid ◽  
Kinetic Study ◽  
Glacial Acetic Acid ◽  
Initial Reaction ◽  
First Order ◽  
Kinetically Controlled ◽  
Different Temperatures ◽  
Pseudo First Order

The acetate-catalyzed epimerization of 1,1,1-trichloro-2-hydroxy-3-methyl-4-hexanone has been studied in glacial acetic acid as solvent at five different temperatures. The reaction follows pseudo first-order, reversible kinetics and is associated with an activation energy of 24.0 ± 0.4 kcal/mol. Rate and product studies have shown that epimerization occurs by an enolization–ketonization pathway rather than dehydration–rehydration or retroaldol–aldolization. The ratio of diastereomeric ketols formed by condensation of 2-pentanone and 2-heptanone with chloral does not change as a function of time while the stereochemistry of the chloral addition to cyclohexanone is kinetically controlled during the initial reaction period.

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