Laser spectrometry and kinetics of selected elementary reactions of the acetonyl radical

2004 ◽  
Vol 6 (15) ◽  
pp. 3958-3968 ◽  
Author(s):  
Krisztina Imrik ◽  
Edit Farkas ◽  
Gábor Vasvári ◽  
István Szilágyi ◽  
Dariusz Sarzyński ◽  
...  
2001 ◽  
Vol 105 (32) ◽  
pp. 7508-7513 ◽  
Author(s):  
Felix Güthe ◽  
Helmut Baumgärtel ◽  
Karl-Michael Weitzel

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.


2011 ◽  
Vol 37 (4) ◽  
pp. 371-421 ◽  
Author(s):  
Judit Zádor ◽  
Craig A. Taatjes ◽  
Ravi X. Fernandes

1985 ◽  
Vol 89 (23) ◽  
pp. 5066-5074 ◽  
Author(s):  
G. C. Light ◽  
R. R. Herm ◽  
J. H. Matsumoto

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.


1999 ◽  
Vol 584 ◽  
Author(s):  
Carlo Cavallotti ◽  
Valeria Bertani ◽  
Maurizio Masi ◽  
Sergio Carrà

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.


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