Elementary Reactions of Energy-Selected Fluoroethene and 1,1-Difluoroethene Ions. 2. The Kinetics of HF-Loss

2001 ◽  
Vol 105 (32) ◽  
pp. 7508-7513 ◽  
Author(s):  
Felix Güthe ◽  
Helmut Baumgärtel ◽  
Karl-Michael Weitzel
Keyword(s):  
Elementary Reactions ◽  
Kinetics Of

The kinetics of elementary reactions involving the oxides of sulphur II. Chemical reactions in the sulphur dioxide afterglow

1966 ◽  
Vol 295 (1443) ◽  
pp. 363-379 ◽  
Keyword(s):  
Excited States ◽  
Sulphur Dioxide ◽  
Kinetic Studies ◽  
Absolute Intensity ◽  
Third Order ◽  
Elementary Reactions ◽  
The Third ◽  
Dominant Process ◽  
Recombination Reactions ◽  
Kinetics Of

The main recombination reactions in the sulphur dioxide afterglow are shown to be O + SO 2 + M = SO 3 + M (1) and O + SO + M = SO 2 + M , (2) with rate constants of (4·7 ± 0·8) x 10 15 and (3·2 ± 0·4) x 10 17 cm 6 mole -2 s -1 respectively at 300°K for M = Ar. Reaction (2) is the dominant process removing sulphur monoxide (SO) which is otherwise remarkably unreactive. The absolute intensity of the sulphur dioxide afterglow is found to be I = 1·5 x 10 8 [O] [SO] cm 3 mole -1 s -1 for argon carriers at pressures between 0·25 an d 3·0 mmHg. The afterglow emission comes from three excited states of SO 2 . Spectroscopic and kinetic studies show that these are populated subsequent to or by the third order combination reaction (2). Excited SO 2 is removed mainly by electronic quenching.

Kinetics of elementary reactions in low-temperature autoignition chemistry

2011 ◽  
Vol 37 (4) ◽  
pp. 371-421 ◽  
Author(s):  
Judit Zádor ◽  
Craig A. Taatjes ◽  
Ravi X. Fernandes
Keyword(s):  
Low Temperature ◽  
Elementary Reactions ◽  
Kinetics Of

Kinetics of some gas-phase elementary reactions of boron monofluoride

1985 ◽  
Vol 89 (23) ◽  
pp. 5066-5074 ◽  
Author(s):  
G. C. Light ◽  
R. R. Herm ◽  
J. H. Matsumoto
Keyword(s):  
Gas Phase ◽  
Elementary Reactions ◽  
Kinetics Of

The cobalt-salt-catalyzed autoxidation of benzaldehyde

1956 ◽  
Vol 237 (1210) ◽  
pp. 297-312 ◽  
Keyword(s):  
Initial Phase ◽  
Kinetic Scheme ◽  
Elementary Reactions ◽  
Perbenzoic Acid ◽  
Direct Measurements ◽  
Reaction Proceeds ◽  
Acid Catalyzed ◽  
Kinetics Of ◽  
Radical Interaction ◽  
Termination Process

The autoxidation of benzaldehyde in glacial acetic acid catalyzed by cobalt salts has been studied by kinetic and analytical methods. In the initial phase of the reaction the oxygen reacts quantitatively with the aldehyde to form perbenzoic acid, but as the reaction proceeds the peracid concentration falls below that of the oxygen absorbed due to ( a ) the catalyzed decomposition of the perbenzoic acid, and ( b ) the reaction of the perbenzoic acid with benzaldehyde to give benzoic acid. The relative contributions of these reactions to the decay of the peracid concentration has been determined. The initiating reaction has been shown to be the interaction of the cobaltic ion with the aldehyde according to Co 3+ + C 6 H 5 CHO → Co 2+ + C 6 H 5 CO·. (1) Direct measurements of the rate of this reaction agreed with the value of the rate of initiation determined by an analysis of the kinetics of the rate of the inhibited oxidation. The overall rate of oxidation may be fully explained by the following kinetic scheme: C 6 H 5 CO· + O 2 → C 6 H 5 COOO· (2) C 6 H 5 COOO· + C 6 H 5 CHO → C 6 H 5 COOOH + C 6 H 5 CO· } (propagation), (3) 2C 6 H 5 COOO → inert products (termination). (4) The chain length and the activation energies of the elementary reactions have been determined. The oxidation was inhibited by hydroquinone, diphenylamine and β -napthol and retarded by benzoquinone. The rate of the retarded oxidations satisfied the relation rate of oxidation = k' / k" + [benzoquinone]· By considering the reaction which is responsible for the retardation, C 6 H 5 COOO· + C 6 H 4 O 2 → inert products, (5) in conjunction with the normal termination reaction (4) it is shown that at retarder con­centrations below 10 -3 M radical-radical termination is the more important reaction, but at 10 -1 M retarder concentration radical-radical interaction contributes only 1% to the termination process.

Realization of Detailed Kinetic Models for the Growth of II-VI Compounds: Adopting DFT Calculations and Experimental Evidences

1999 ◽  
Vol 584 ◽  
Author(s):  
Carlo Cavallotti ◽  
Valeria Bertani ◽  
Maurizio Masi ◽  
Sergio Carrà
Keyword(s):  
Experimental Data ◽  
Kinetic Theory ◽  
Gas Phase ◽  
Quantum Chemical ◽  
Kinetic Scheme ◽  
Kinetic Constants ◽  
Surface Processes ◽  
Gas Phase Reactions ◽  
Elementary Reactions ◽  
Kinetics Of

AbstractThe kinetics of deposition of CdTe, ZnS and ZnSe films was studied. An overall microkinetically reversible kinetic scheme consisting of elementary reactions, comprehensive of gas phase and surface processes was developed. Kinetic constants of gas phase reactions were either found in the literature or determined through quantum chemistry methods. Kinetic constants of surface reactions were first guessed combining kinetic theory with quantum chemical calculations and then their values were refined to reproduce experimental data. The kinetics schemes so developed were tested through the simulation of deposition reactors. Measured growth rates and gas phase compositions were thus compared with those calculated. The major finding of this studies is that the growth of CdTe, ZnS and ZnSe can be represented adopting a surface kinetic scheme constituted essentially by the same fundamental steps.

Kinetics of the reaction H + C2H6 → H2 + C2H5 in the temperature region of 1000 K

1984 ◽  
Vol 62 (1) ◽  
pp. 86-91 ◽  
Author(s):  
J.-R. Cao ◽  
M. H. Back
Keyword(s):  
Equilibrium Constant ◽  
Rate Constant ◽  
Temperature Region ◽  
Recent Measurement ◽  
Hydrogen Atoms ◽  
Elementary Reactions ◽  
Temperature Range ◽  
Hydrogen Molecules ◽  
Kinetics Of ◽  
Rate Controlling Step

A system for the measurement of rate constants for elementary reactions of hydrogen atoms in the temperature region of 1000 K is described. The concentration of hydrogen atoms is controlled by the equilibrium constant for dissociation of hydrogen molecules. The kinetics of the rate of conversion of ethane to ethylene in this system has been studied over the temperature range 876–1016 K. The results show that the rate-controlling step is[Formula: see text]and the value obtained for the rate constant is[Formula: see text](R = 1.987 cal mol−1 deg−1). This value is compared with values obtained from other methods over the temperature range 300–1400 K. Combination with a recent measurement of the rate constant for the reverse reaction yields an experimental value for the equilibrium constant for the reaction.

scholarly journals Particle-based simulation reveals macromolecular crowding effects on the Michaelis-Menten mechanism

2018 ◽  
Author(s):  
Daniel R. Weilandt ◽  
Vassily Hatzimanikatis
Keyword(s):  
Computational Models ◽  
Enzyme Reaction ◽  
Phosphoglycerate Mutase ◽  
Cell Physiology ◽  
Enzymatic Reactions ◽  
Elementary Reactions ◽  
Elementary Kinetics ◽  
Kinetics Of

AbstractMany computational models for analyzing and predicting cell physiology rely onin vitrodata, collected in dilute and cleanly controlled buffer solutions. However, this can mislead models because about 40% of the intracellular volume is occupied by a dense mixture of proteins, lipids, polysaccharides, RNA, and DNA. These intracellular macromolecules interact with enzymes and their reactants and affect the kinetics of biochemical reactions, makingin vivoreactions considerably more complex than thein vitrodata indicates. In this work, we present a new type of kinetics that captures and quantifies the effect of volume exclusion and any other spatial phenomena on the kinetics of elementary reactions. We further developed a framework that allows for the efficient parameterization of this type of kinetics using particle simulations. Our formulation, entitled GEneralized Elementary Kinetics (GEEK), can be used to analyze and predict the effect of intracellular crowding on enzymatic reactions and was herein applied to investigate the influence of crowding on phosphoglycerate mutase inEscherichia coli, which exhibits prototypical reversible Michaelis-Menten kinetics. Current research indicates that many enzymes are reaction limited and not diffusion limited, and our results suggest that the influence of fractal diffusion is minimal for these reaction-limited enzymes. Instead, increased association rates and decreased dissociation rates lead to a strong decrease in the effective maximal velocitiesVmaxand the effective Michaelis-Menten constantsKMunder physiologically relevant volume occupancies. Finally, the effects of crowding in the context of a linear pathway were explored, with the finding that crowding can have a redistributing effect, relative to ideal conditions, on the effective flux responses in the case of two-fold enzyme overexpression. We suggest that the presented framework in combination with detailed kinetics models will improve our understanding of enzyme reaction networks under non-ideal conditions.

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