Kinetics of the reaction between atomic nitrogen and molecular oxygen in the ground ( 3 ∑ - g ) and first excited ( 1 ∆ g ) states

1970 ◽  
Vol 316 (1527) ◽  
pp. 539-550 ◽  
Keyword(s):  
Nitric Oxide ◽  
Molecular Oxygen ◽  
Rate Constants ◽  
Room Temperature ◽  
Atomic Nitrogen ◽  
D Region ◽  
Exponential Factors ◽  
The Difference ◽  
Kinetics Of ◽  
Arrhenius Expression

Rate constants for the reaction N + O 2 ( 1 ∆ g ) → k 1 NO + O (1) have been measured at four temperatures, and fitted to an Arrhenius expression, k 1 = A exp ( ─ E a / RT ). The results indicate that A ≤ 2 x 10 -14 molecule -1 cm 3 s -1 and < 1.2 kcal (5.0 kJ ) mol -1 : at room temperature (300 K ), k 1 = 2.7 ± 1.0 x 10 -15 molecule -1 cm 3 s -1 . Reaction (1) cannot, therefore, proceed fast enough at 200 K for it to be an important source of nitric oxide in the atmospheric D-region. The rate constant for the reaction N + O 2 ( 3 ∑ ─ g ) → k 2 NO + O (2) has been measured at 302 K to be 1.08 ± 0.10 x 10 -16 molecule -1 cm 3 s -1 . This value, taken together with the data of earlier workers, suggests that k 2 = 1.5 x 10 -11 exp (—7.1/ RT ) molecule -1 cm 2 s -1 . A possible explanation for the difference in pre-exponential factors for reactions (1) and (2) is presented.

Synthesis and kinetics of decomposition of some novel S-nitrosothiols

1999 ◽  
Vol 77 (5-6) ◽  
pp. 550-556 ◽  
Author(s):  
Andrew P Munro ◽  
D Lyn H. Williams
Keyword(s):  
Nitric Oxide ◽  
Room Temperature ◽  
Alternative Pathway ◽  
Copper Catalysis ◽  
Induction Periods ◽  
Kinetics Of Decomposition ◽  
Initial Generation ◽  
Kinetics Of ◽  
Reaction Schemes

TheS-nitrosothiols 2-acetamido-2-deoxy-S-nitroso-1-thio-β-D-glucopyranose 3,4,6-triacetate (GPSNO) and S-nitroso-N-carbamyl-D,L-penicillamine (SNCP) were synthesized by S-nitrosation of the corresponding thiols, isolated, and fully characterized. The nitrosothiol (TGSNO) from 1-thioglycerol was obtained as a red gelatinous liquid, which decomposed rapidly at room temperature and so was not characterized. The kinetics of decomposition of GPSNO showed that there is a surprisingly large thermal pathway overlaid with a Cu2+/RS- catalyzed reaction. The results strongly suggest that the product disulfide complexes Cu2+ (for which there is some spectral evidence), leading to incomplete conversion by that route. Ascorbate also acts as a Cu2+ reductant. Another S-nitroso sugar, S-nitroso-1-thio-β-D-glucose (SNTG), behaved very similarly from solutions generated and used in situ. The decomposition of TGSNO shows induction periods suggesting that slow initial generation of Cu+ (the true catalyst) is taking place. There appears to be also a significant alternative pathway (analogous to that found for GPSNO), where the rate appears to be independent of [Cu2+], but very unusually this pathway is effectively halted by addition of EDTA either at the start of the reaction or at a later time. Reaction schemes are put forward to account for these unusual reaction characteristics.Key words: S-nitrosothiols, nitric oxide, ascorbate, copper catalysis.

scholarly journals Research of High-Temperature Heat and Mass Transfer and Kinetics of Phase Transformations during combustion higher alkanes in the air

2015 ◽  
Vol 16 (2) ◽  
pp. 347-350
Author(s):  
S.G. Orlovska ◽  
A.O. Odnostalko ◽  
F.F. Karimova ◽  
M.S. Shkoropado
Keyword(s):  
Mass Transfer ◽  
High Temperature ◽  
Phase Transformations ◽  
Burning Rate ◽  
Heat And Mass Transfer ◽  
Rate Constants ◽  
Room Temperature ◽  
Combustion Kinetics ◽  
Temperature Heat ◽  
Kinetics Of

 The paper presents a study of high-temperature heat and mass transfer and combustion kinetics of octadecane particle in room temperature air taking in consideration fuel heating, melting and evaporation. The consecutive stages of droplet combustion are described. Burning rate constants and flame heights are determined for droplets with different initial diameters

A kinetic model of the thiazide-sensitive Na-Cl cotransporter

1999 ◽  
Vol 276 (6) ◽  
pp. F952-F959 ◽  
Author(s):  
Hangil Chang ◽  
Toshiro Fujita
Keyword(s):  
Rate Constants ◽  
Linear Equations ◽  
State Diagram ◽  
Inhibitory Effect ◽  
Experimental Results ◽  
Kinetic Properties ◽  
Sodium Influx ◽  
Substrate Transport ◽  
The Difference ◽  
Kinetics Of

The aim of this study was to construct a numerical model of the thiazide-sensitive Na-Cl cotransporter (TSC) that can predict kinetics of thiazide binding and substrate transport of TSC. We hypothesized that the mechanisms underlying these kinetic properties can be approximated by a state diagram in which the transporter has two binding sites, one for sodium and another for chloride and thiazide. On the basis of the state diagram, a system of linear equations that should be satisfied in the steady state was postulated. Numerical solution of these equations yielded model prediction of kinetics of thiazide binding and substrate transport. Rate constants, which determine transitional rates between states, were systematically adjusted to minimize a penalty function that was devised to quantitatively estimate the difference between model predictions and experimental results. With the resultant rate constants, the model could simulate the following experimental results: 1) dissociation constant of thiazide in the absence of sodium and chloride; 2) inhibitory effect of chloride on thiazide binding; 3) stimulatory effect of sodium on thiazide binding; 4) combined effects of sodium and chloride on thiazide binding; 5) dependence of sodium influx on extracellular sodium and chloride; and 6) inhibition of sodium influx by extracellular thiazide. We conclude that known kinetic properties of TSC can be predicted by a model which is based on a state diagram.

THE EFFECT OF MOLECULAR OXYGEN ON THE REACTION OF OXYGEN ATOMS WITH cis-2-PENTENE

1959 ◽  
Vol 37 (5) ◽  
pp. 953-965 ◽  
Author(s):  
S. Sato ◽  
R. J. Cvetanović
Keyword(s):  
Nitric Oxide ◽  
Nitrous Oxide ◽  
Nitrogen Dioxide ◽  
Molecular Oxygen ◽  
Reaction Mechanisms ◽  
Room Temperature ◽  
Pressure Independent ◽  
Decomposition Of Nitrous Oxide ◽  
Oxygen Atoms

The effect of the presence of nitrogen, oxygen, and nitric oxide on the reaction between cis-2-pentene and oxygen atoms has been investigated at room temperature (25 ± 2 °C). For production of oxygen atoms use was made of mercury-photosensitized decomposition of nitrous oxide and of the photolysis of nitrogen dioxide at 3660 Å.In the N2O work, the presence of molecular oxygen induced the formation of acetaldehyde, propanal, methanol, and ethanol. In the NO2 work, the amounts of acetaldehyde, propanal, and ethyl nitrate formed increased rapidly with increasing pressure of molecular oxygen. Possible reaction mechanisms for the formation of these compounds are discussed.Additional information was obtained on the pressure-independent fragmentation in the reaction of oxygen atoms with cis-2-pentene.

Temperature Dependence of the Photoinduced Degradation and Annealing in a-Si:H

2000 ◽  
Vol 609 ◽  
Author(s):  
Niko Schultz ◽  
P. Craig Taylor
Keyword(s):  
Temperature Dependence ◽  
Room Temperature ◽  
Dangling Bond ◽  
Defect States ◽  
Slow Increase ◽  
Spin Resonance ◽  
The Difference ◽  
Kinetics Of ◽  
Defect Densities ◽  
Spin Densities

ABSTRACTWe investigated the temperature dependence of the production and annealing kinetics of the light induced defect states in a:Si:H by electron spin resonance (ESR). At low temperatures (T ∼ 25 K) the silicon dangling bond production is about half as efficient as it is at 300 K. Defects, which are created below about 100 K, almost entirely anneal at room temperature. A sample of a-Si:H, which is subjected to several photo-excitation and annealing cycles, shows a very slow increase of both the degraded and annealed defect densities. The difference in the spin densities between the annealed and degraded states decreases with an increasing number of degradation/annealing cycles.

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