Temperature and Oxygen Effect on Oscillations of the Belousov-Zhabotinsky Reaction with 2-Oxopentanedioic Acid as Substrate

2000 ◽  
Vol 65 (12) ◽  
pp. 1839-1847 ◽  
Author(s):  
Daniela Bala ◽  
Ľudovít Treindl
Keyword(s):  
Temperature Dependence ◽  
Activation Parameters ◽  
Average Frequency ◽  
Oxygen Effect ◽  
Redox Catalyst ◽  
Influence Of Temperature On ◽  
Effect Of Oxygen ◽  
Belousov Zhabotinsky Reaction ◽  
Multi Mode ◽  
Autocatalytic Oxidation

The temperature dependence of the influence of oxygen on the Belousov-Zhabotinsky (BZ) system with a Ce(IV)-Ce(III) redox catalyst and 2-oxopentanedioic acid as substrate and on the autocatalytic oxidation of Ce(III) ions with bromate was studied in detail. The influence of temperature on the induction period, the period of the second oscillation, duration and number of oscillations, and finally on the average frequency of oscillations, was investigated both in oxygen and in nitrogen. The corresponding activation parameters have been determined and discussed. The most pregnant effect of oxygen is observed on the temperature dependence of the duration and the number of oscillations. The value for enthalpy of activation is more than 50 kJ mol-1 higher in oxygen than in nitrogen. The presence of oxygen may generate chaotic behaviour or multi-mode oscillations since in the presence of oxygen, new intermediates in the BZ system are formed, thereby increasing its complexity.

Influence of oxygen on Belousov-Zhabotinskii reaction

1980 ◽  
Vol 45 (4) ◽  
pp. 1168-1172 ◽  
Author(s):  
Ľudovít Treindl ◽  
Peter Fabian
Keyword(s):  
Citric Acid ◽  
Induction Period ◽  
Malonic Acid ◽  
Rate Constants ◽  
Activation Parameters ◽  
Oscillation Period ◽  
Redox Catalyst ◽  
Basic Parameters ◽  
Effect Of Oxygen ◽  
Belousov Zhabotinskii Reaction

This work deals with the effect of oxygen on basic parameters of the Belousov-Zhabotinskii reaction in the presence of Ce4+/Ce3+ redox catalyst and malonic acid, citric acid, or 2,4-pentanedione as substrates. Oxygen lowers the duration of the induction period and the first oscillation period as well as the corresponding activation parameters. Oxygen lowers also rate constants and activation parameters for oxidation of malonic and citric acids with Ce4+ ions. It is concluded that the effect of oxygen on the Belousov-Zhabotinskii reaction consists mainly in its catalytic influence on the oxidation of the substrate with Ce4+ ions.

scholarly journals The role of enzyme dynamics and tunnelling in catalysing hydride transfer: studies of distal mutants of dihydrofolate reductase

2006 ◽  
Vol 361 (1472) ◽  
pp. 1307-1315 ◽  
Author(s):  
Lin Wang ◽  
Nina M Goodey ◽  
Stephen J Benkovic ◽  
Amnon Kohen
Keyword(s):  
Temperature Dependence ◽  
Dihydrofolate Reductase ◽  
Isotope Effects ◽  
Hydride Transfer ◽  
Activation Parameters ◽  
Physical Nature ◽  
Enzyme Dynamics ◽  
Temperature Dependences ◽  
Donor Acceptor ◽  
Significant Temperature

Residues M42 and G121 of Escherichia coli dihydrofolate reductase ( ec DHFR) are on opposite sides of the catalytic centre (15 and 19 Å away from it, respectively). Theoretical studies have suggested that these distal residues might be part of a dynamics network coupled to the reaction catalysed at the active site. The ec DHFR mutant G121V has been extensively studied and appeared to have a significant effect on rate, but only a mild effect on the nature of H-transfer. The present work examines the effect of M42W on the physical nature of the catalysed hydride transfer step. Intrinsic kinetic isotope effects (KIEs), their temperature dependence and activation parameters were studied. The findings presented here are in accordance with the environmentally coupled hydrogen tunnelling. In contrast to the wild-type (WT), fluctuations of the donor–acceptor distance were required, leading to a significant temperature dependence of KIEs and deflated intercepts. A comparison of M42W and G121V to the WT enzyme revealed that the reduced rates, the inflated primary KIEs and their temperature dependences resulted from an imperfect potential surface pre-arrangement relative to the WT enzyme. Apparently, the coupling of the enzyme's dynamics to the reaction coordinate was altered by the mutation, supporting the models in which dynamics of the whole protein is coupled to its catalysed chemistry.

Concerning the Problem of the Isokinetic Relationship. IV. The Evaluation of the Isosubstituent Hammett Parameter by Means of Isokinetic and Isoequilibrium Temperatures

1986 ◽  
Vol 39 (2) ◽  
pp. 199 ◽  
Author(s):  
W Linert
Keyword(s):  
Temperature Dependence ◽  
Activation Parameters ◽  
Common Point ◽  
Isokinetic Temperature ◽  
Benzoic Acids ◽  
Reaction Series ◽  
Isokinetic Relationship ◽  
The Common ◽  
Point Of Intersection ◽  
Hammett Parameter

The interrelation between the isosubstituent and the isokinetic relationship is developed and tested for several Hammett reaction series. Two methods of approach to relate the temperature dependence of Arrhenius and Hammett plots are given, one utilizing the isoequilibrium temperature of the ionization of benzoic acids and the other the isokinetic temperature of the respective Hammett reaction series. The efficiency of the approaches for the evaluation of the coordinates of the common point of intersection in the Hammett plot, i.e. the characteristics of the isosubstituent relationship, are compared with each other and with experimental results. With the former approach, by using the activation parameters of only one (commonly the unsubstituted ) member of the series, the temperature dependence of a Hammett line can be predicted provided that the isokinetic temperature of the Hammett series does not approach the experimental temperature range. Otherwise the latter approach must be used which, however, needs the temperature dependence of at least two (or better more) members of the reaction series.

An oxygen effect in dry bacterial spores and its temperature dependence

1959 ◽  
Vol 17 (3) ◽  
pp. 550-554 ◽  
Author(s):  
E.L. Powers ◽  
R.B. Webb ◽  
C.F. Ehret
Keyword(s):  
Temperature Dependence ◽  
Oxygen Effect ◽  
Bacterial Spores

Inhibitory effect of oxygen on excitation waves in the Belousov–Zhabotinsky reaction with different excitability

2015 ◽  
Vol 618 ◽  
pp. 6-10
Author(s):  
Jiraporn Luengviriya ◽  
Metinee Phantu ◽  
Stefan C. Müller ◽  
Chaiya Luengviriya
Keyword(s):  
Inhibitory Effect ◽  
Effect Of Oxygen ◽  
Belousov Zhabotinsky Reaction

scholarly journals Temperature dependence of the indentation size effect

2010 ◽  
Vol 25 (7) ◽  
pp. 1225-1229 ◽  
Author(s):  
Oliver Franke ◽  
Jonathan C. Trenkle ◽  
Christopher A. Schuh
Keyword(s):  
High Temperature ◽  
Size Effect ◽  
Temperature Dependence ◽  
Thermal Activation ◽  
Indentation Size Effect ◽  
Inert Atmosphere ◽  
Length Scale ◽  
Indentation Size ◽  
Influence Of Temperature ◽  
Influence Of Temperature On

The influence of temperature on the indentation size effect is explored experimentally. Copper is indented on a custom-built high-temperature nanoindenter at temperatures between ambient and 200 °C, in an inert atmosphere that precludes oxidation. Over this range of temperatures, the size effect is reduced considerably, suggesting that thermal activation plays a major role in determining the length scale for plasticity.

Reaction of 1,3-diphenyltriazene with phenyl isocyanate. Solvent effect, activation parameters and kinetic isotopic effect

1981 ◽  
Vol 46 (6) ◽  
pp. 1376-1382
Author(s):  
Erhard Lejdar ◽  
Oldřich Pytela ◽  
Miroslav Večeřa ◽  
Pavel Vetešník
Keyword(s):  
Hydrogen Atom ◽  
Solvent Effect ◽  
Temperature Dependence ◽  
Activation Parameters ◽  
Phenyl Isocyanate ◽  
Isotopic Effect ◽  
Imino Group ◽  
Reaction Velocity ◽  
Kinetic Isotopic Effect ◽  
Previous Communication

Effect of 14 solvents has been studied on the reaction of phenyl isocyanate with 1,3-diphenyltriazene. For ten of these solvents temperature dependence of the reaction velocity has been determined and the respective activation parameters calculated. Hydrogen atom of the triazene imino group has been replaced by deuterium, and the deuterium kinetic isotopic effect has been studied in seven solvents. The results confirm the mechanism suggested in a previous communication.

scholarly journals Temperature Dependence of Activation Parameters in the Neutral Ester Hydrolysis in Methanol--Water Solutions.

1983 ◽  
Vol 37b ◽  
pp. 755-760 ◽  
Author(s):  
Liisa T. Kanerva ◽  
Einar Uggerud ◽  
Kristin Brobakke ◽  
Georg E. Carlberg ◽  
Olov Sterner ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Activation Parameters ◽  
Ester Hydrolysis ◽  
Water Solutions
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