scholarly journals Kinetics of Oxidation of Hexakis (P-chloroaniline) Cobalt (II) Chloride by Potassium Iodate

2003 ◽  
Vol 2 (1) ◽  
pp. 34-38
Author(s):  
B. Edison ◽  
S. Peter
Keyword(s):  
Kinetic Parameters ◽  
Aqueous Medium ◽  
Neutral Salt ◽  
Complex Solution ◽  
Potassium Iodate ◽  
Kinetics Of Oxidation ◽  
First Order ◽  
First Order Kinetics ◽  
Kinetics Of

Vit B12 is an important complex of cobalt3 . The rate of oxidation of the Synthesized complex Hexakis(p-chloral aniline) cobalt((II) chloride follows first order kinetics with respect to the complex and oxidant potassium iodate1,2,4-8 in aqueous medium. Increasing in the concentration of complex solution increases the rate of the oxidation. The rate of the reaction is studied by changing the acid concentrations of the medium , by changing the temperature and by introducing the neutral salt (NaCl) in the Medium. From this study the kinetic parameters Ea, A,∆S#,∆G#,∆H# are found out. From the observed fats it is inferred that the reaction follows three steps.

Kinetics and Mechanism of Oxidation of Dimethyl Sulphoxide by Mono- and Di-Substituted N,N-Dichlorobenzenesulphonamides in Aqueous Acetic Acid

2003 ◽  
Vol 58 (8) ◽  
pp. 787-794 ◽  
Author(s):  
B.Thimme Gowda ◽  
K. L. Jayalakshmi ◽  
K. Jyothi
Keyword(s):  
Acetic Acid ◽  
Benzene Ring ◽  
Dimethyl Sulphoxide ◽  
Aqueous Acetic Acid ◽  
Isokinetic Temperature ◽  
Free Energies ◽  
Kinetics Of Oxidation ◽  
First Order ◽  
First Order Kinetics ◽  
Kinetics Of

In an effort to introduce N,N-dichloroarylsulphonamides of different oxidising strengths, four mono- and five di-substituted N,N-dichlorobenzenesulphonamides are prepared, characterised and employed as oxidants for studying the kinetics of oxidation of dimethyl sulphoxide (DMSO) in 50% aqueous acetic acid. The reactions show first order kinetics in [oxidant], fractional to first order in [DMSO] and nearly zero order in [H+]. Increase in ionic strength of the medium slightly increases the rates, while decrease in dielectric constant of the medium decreases the rates. The results along with those of the oxidation of DMSO by N,N-dichlorobenzenesulphonamide and N,N-dichloro-4- methylbenzenesulphonamide have been analysed. Effective oxidising species of the oxidants employed in the present oxidations is Cl+ in different forms, released from the oxidants. Therefore the introduction of different substituent groups into the benzene ring of the oxidant is expected to affect the ability of the reagent to release Cl+ and hence its capacity to oxidise the substrate. Significant changes in the kinetic and thermodynamic data are observed in the present investigations with change of substituent in the benzene ring. The electron releasing groups such as CH3 inhibit the ease with which Cl+ is released from the oxidant, while electron-withdrawing groups such as Cl enhance this ability. The Hammett equation, log kobs = −3.19 + 1.05 σ , is found to be valid for oxidations by all the p-substituted N,N-dichlorobenzenesulphonamides. The substituent effect on the energy of activation, Ea and log A for the oxidations is also analysed. The enthalpies and free energies of activation correlate with an isokinetic temperature of 320 K.

scholarly journals Nanosized centers for mercury(II) ions adsorption on a surface of modified silica

2008 ◽  
Vol 6 (4) ◽  
pp. 581-591 ◽  
Author(s):  
Lyudmila Belyakova ◽  
Oleksandra Shvets ◽  
Diana Lyashenko
Keyword(s):  
Aqueous Medium ◽  
Batch Adsorption ◽  
Modified Silica ◽  
First Order ◽  
Chemically Modified ◽  
First Order Kinetics ◽  
Adsorption Data ◽  
Pseudo Second Order ◽  
Kinetics Of ◽  
Second Order Equations

AbstractThe present work investigates the adsorptive interactions of Hg(II) ions in aqueous medium with hydroxylated silica, aminopropylsilica and silica chemically modified by β-cyclodextrin. Batch adsorption studies were carried out with various agitation times and mercury(II) concentrations. The maximum adsorption was observed within 15–30 min of agitation. The kinetics of the interactions, tested with the model of Lagergren for pseudo-first and pseudo-second order equations, showed better agreement with first order kinetics (k1 = 3.4 ± 0.2 to 5.9 ± 0.3 min−1). The adsorption data gave good fits with Langmuir isotherms. The results have shown that β-cyclodextrin-containing adsorbent has the largest adsorption specificity to Hg(II): K L = 4125 ± 205 mmol−1. “β-cyclodextrin-NO3-” inclusion complexes with ratio 1: 1 and super molecules with composition C42H70O35 ⊎ 3 Hg(NO3)2 are formed on the surface of β-cyclodextrin-containing silica.

Kinetics of oxidation of the chromium(II) acetate dimer by iodine: an example of mixed zero-order/first-order kinetics

1985 ◽  
Vol 24 (25) ◽  
pp. 4366-4371 ◽  
Author(s):  
Ladislav M. Wilson ◽  
Roderick D. Cannon
Keyword(s):  
Zero Order ◽  
Kinetics Of Oxidation ◽  
First Order ◽  
First Order Kinetics ◽  
Kinetics Of

Investigations into the kinetics and stoichiometry of bacterial oxidation of covellite (CuS) using a polarographic oxygen probe

1978 ◽  
Vol 24 (8) ◽  
pp. 998-1003 ◽  
Author(s):  
Pamela A. D. Rickard ◽  
Donald G. Vanselow
Keyword(s):  
Oxygen Uptake Rate ◽  
Zero Order ◽  
Bacterial Oxidation ◽  
Kinetics Of Oxidation ◽  
First Order ◽  
Cupric Ion ◽  
First Order Kinetics ◽  
Zero Order Kinetics ◽  
Cupric Sulphate ◽  
Kinetics Of

"Oxygraph" apparatus was used to measure quantitatively the kinetics of oxidation of synthetic covellite (CuS) in the presence and absence of Thiobacillus species. The expected stoichiometric relationship between oxygen consumed and cupric sulphate produced was verified by atomic absorption assays of cupric ion and sulphate ion. Thiobacillus cultures markedly increased the oxidation rate.The dependence of each oxygen-uptake rate on oxygen concentration was also measured. Sterile controls and some bacterial cultures showed first-order kinetics while other cultures showed zero-order kinetics.Addition of biological inhibitors to reacting slurries revealed that cultures showing first-order kinetics did not oxidize CuS itself but merely oxidized elemental sulphur formed by non-enzymic oxidation of CuS. Cultures showing zero-order kinetics oxidized CuS in a way that resulted in all oxygen reduction being enzymic. This mechanism possibly involves the cyclic oxidation and reduction of soluble iron.

scholarly journals Kinetics of Oxidation of Cobalt(III) Complexes ofaAcids by Hydrogen Peroxide in the Presence of Surfactants

2008 ◽  
Vol 5 (1) ◽  
pp. 43-51 ◽  
Author(s):  
Mansur Ahmed ◽  
K. Subramani
Keyword(s):  
Hydrogen Peroxide ◽  
Electron Transfer ◽  
Bond Cleavage ◽  
Micellar Medium ◽  
Hydroxy Acids ◽  
Peroxide Oxidation ◽  
Kinetics Of Oxidation ◽  
First Order ◽  
First Order Kinetics ◽  
Kinetics Of

Hydrogen peroxide oxidation of pentaamminecobalt(III) complexes ofα-hydroxy acids at 35°C in micellar medium has been attempted. In this reaction the rate of oxidation shows first order kinetics each in [cobalt(III)] and [H2O2]. Hydrogen peroxide induced electron transfer in [(NH3)5CoIII-L]2+complexes ofα-hydroxy acids readily yields 100% of cobalt(II) with nearly 100% of C-C bond cleavage products suggesting that it behaves mainly as one equivalent oxidant in micellar medium. With unbound ligand also it behaves only as C-C cleavage agent rather than C-H cleavage agent. With increasing micellar concentration an increase in the rate is observed.

Oxidation of the mercurous ion by peroxidase

1986 ◽  
Vol 64 (5) ◽  
pp. 969-972 ◽  
Author(s):  
Donald C. Wigfield ◽  
Season Tse
Keyword(s):  
Elemental Mercury ◽  
Order Rate Constant ◽  
Kinetics Of Oxidation ◽  
First Order ◽  
Order Rate ◽  
First Order Kinetics ◽  
Cold Vapour ◽  
Pseudo First Order ◽  
Kinetics Of ◽  
Mercurous Ion

The kinetics of oxidation of the mercurous ion by peroxidase have been measured by following the disappearance of mercurous ion using cold-vapour atomic absorption spectroscopy. Pseudo-first-order kinetics are observed with respect to mercurous ion, and the pseudo-first-order rate constants are linearly related to peroxidase concentration, showing first-order dependence on peroxidase. This behaviour is identical to oxidation of elemental mercury, and the second-order rate constant, 1.44 × 104 M−1 s−1 at 23 °C, is also, within experimental error, the same as that for elemental mercury oxidation. The data are interpreted in terms of peroxidase-induced disproportionation of the mercurous dimer, followed by two-electron oxidation of zero-valent mercury.

scholarly journals Kinetics of Oxidation of Benzoin by N. Bromosuccinimide

2005 ◽  
Vol 4 (1) ◽  
pp. 55-61
Author(s):  
R. Sridharan ◽  
N. Mathiyalagan
Keyword(s):  
Dielectric Constant ◽  
Acetic Acid ◽  
Reaction Rate ◽  
Activation Parameters ◽  
Aqueous Acetic Acid ◽  
Kinetics Of Oxidation ◽  
First Order ◽  
First Order Kinetics ◽  
Retarding Effect ◽  
Kinetics Of

Kinetics of Oxidation of Benzoin by N. Bromosuccinimide[NBS] 80% aqueous acetic acid has been investigated. The reaction follows first-order kinetics with respect to both[NBS] and [benzoin]. The effect of varying ionic strength and dielectric constant indicate the reaction is dipole-dipole type. Addition of succinimide(>NH), has a retarding effect on the rate of oxidation. The product of oxidation is benzil. By studying the effect of temparature on the reaction rate, the Arrhenius and the activation parameters have been calculated. A suitable mechanism has been proposed and a rate low explaining the experiment results is derived.

Simulation of the experimental thermal cleaning procedure in LiF:Mg,Ti and investigation of the origin of the first-order kinetics of its peaks

2015 ◽  
Vol 29 (34) ◽  
pp. 1550226
Author(s):  
Mokhtar Halimi ◽  
Dahane Kadri ◽  
Abdelmalek Mokeddem
Keyword(s):  
Kinetic Parameters ◽  
Phenomenological Model ◽  
Recombination Center ◽  
Electron Trapping ◽  
Cleaning Procedure ◽  
First Order ◽  
Thermal Cleaning ◽  
First Order Kinetics ◽  
Kinetics Of ◽  
Random Variation

In this paper, the simulation of the thermal cleaning procedure in LiF:Mg,[Formula: see text]Ti as well as the investigation of the origin of its glow-peaks have been performed by six electron trapping levels and one recombination center phenomenological model. The most generally accepted parameter of the glow-peaks 1 to 5 of LiF:Mg,[Formula: see text]Ti is their first-order kinetics; this was particularly investigated by the use of the random variation of the kinetic parameters method.

scholarly journals Polyethylene Glycols as Efficient Catalysts for the Oxidation of Xanthine Alkaloids by Ceric Ammonium Nitrate in Acetonitrile: A Kinetic and Mechanistic Approach

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
S. Shylaja ◽  
K. C. Rajanna ◽  
K. Ramesh ◽  
K. Rajendar Reddy ◽  
P. Giridhar Reddy
Keyword(s):  
Ammonium Nitrate ◽  
Elevated Temperatures ◽  
Ceric Ammonium Nitrate ◽  
Kinetics Of Oxidation ◽  
First Order ◽  
First Order Kinetics ◽  
Mechanistic Approach ◽  
Enzymatic Model ◽  
Poly Ethylene ◽  
Kinetics Of

Kinetics of oxidation of xanthine alkaloids, such as Xanthine (XAN), hypoxanthine (HXAN), caffeine (CAF), theophylline (TPL), and theobromine (TBR), have been studied with ceric ammonium nitrate (CAN) using poly ethylene glycols (PEG) as catalysts. Reaction obeyed first order kinetics in both [CAN] and [Xanthine alkaloid]. Highly sluggish CAN-xanthine alkaloid reactions (in acetonitrile media even at elevated temperatures) are enhanced in presence PEGs (PEG-200, -300, -400, -600). An increase in [PEG] increased the rate of oxidation linearly. This observation coupled with a change in absorption of CAN in presence of PEG, [H–(OCH2–CH2)n–O–NH4Ce(NO3)4(CH3CN)] (PEG bound CAN species), is considered to be more reactive than CAN. The mechanism of oxidation in PEG media has been explained by Menger-Portnoy’s enzymatic model.

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