scholarly journals Ligand Exchange Kinetics of 2,2’-Bipyridine with Nitrilotriacetatonickelate(II)

2018 ◽  
Vol 6 (2) ◽  
pp. 71-75
Author(s):  
Larry H Kolopajlo ◽  
Shelby Coleman
Keyword(s):  
Rate Constant ◽  
Ligand Exchange ◽  
Order Conditions ◽  
Hydrogen Ion ◽  
Ligand Exchange Reaction ◽  
First Order ◽  
Exchange Kinetics ◽  
Pseudo First Order ◽  
Ph Range ◽  
Kinetics Of

The kinetics of the ligand exchange reaction between 2,2’-bipyridine (bipy) and NiNTA- was studied over the pH range 4.7 to 7.5 at 25.0 0C and an ionic strength of 0.10 M by following the formation of Ni(bipy)3 product at 307 nm. All reactions were run under pseudo-first order conditions with a [bipy]/[NiNTA-] ratio of at least 20. The reaction is first-order with respect to each of NiNTA- and to bipy. The reaction is also accelerated by hydrogen ion. The rate constant for the hydrogen ion unassisted addition of bipy to NiNTA- is 0.671 M-1 s-1. The reaction is also first-order in hydrogen ion with a rate constant for the hydrogen ion assisted addition of bipy to NiNTA- is 9.45 x 104 M-2 s-1. A dissociative type mechanism accelerated by hydrogen ion is proposed. The work has significance by showing that NiEDDA and NiNTA, both aminopolyacrboxylate complexes react by the same mechanism.

scholarly journals Kinetics of the reduction of 4-amino and 4-cyanopyridinechlorocobaloximes by iron(II)

2006 ◽  
Vol 71 (12) ◽  
pp. 1311-1321 ◽  
Author(s):  
A. Dayalan ◽  
C. Revathi
Keyword(s):  
Nmr Spectroscopy ◽  
Protonation Constant ◽  
Protonated Form ◽  
Order Conditions ◽  
Hydrogen Ion ◽  
Ion Concentrations ◽  
First Order ◽  
Ir And Nmr Spectroscopy ◽  
Pseudo First Order ◽  
Kinetics Of

Cobaloximes such as trans[Co(dmgH) 2(Py-NH2)Cl] and trans- [Co(dmgH) 2(Py-CN)Cl], where, dmgH = dimethylglyoximato anion, Py-NH 2 = 4-aminopyiridne and Py-CN = 4-cyanopyridine, were prepared and characterized by elemental analysis, UV-VIS, IR and NMR spectroscopy. The kinetics of iron(II) reduction of the complexes were studied spectrophotometrically at 300 nm in 2% (v/v) DMSO-H2O medium at 27?0.1?C and I = 0.25 M (LiClO4) at various hydrogen ion concentrations in the range 2.5 x 10-4 to 5.0x10-2 M under pseudo-first-order conditions using an excess of the reductant. The inverse dependence of rate on [H+] suggests an equilibrium between the protonated and unportonated forms of the complexes, the protonated form reacting slower than the unprotonated form. Computation of the data enabled the evaluation of the rate constants for the protonated and unprotonated from of the complexes, leading to an evaluation of the protonation constant for the complexes. .

Oxidation of Nickel(II) and Manganese(II) by Peroxodisulfate in Aqueous Solution in the Presence of Molybdate. Crystal Structure of the (NH4)6[NiMo9O32].6H2O Product

1992 ◽  
Vol 45 (12) ◽  
pp. 1943 ◽  
Author(s):  
SJ Dunne ◽  
RC Burns ◽  
GA Lawrance
Keyword(s):  
Rate Constant ◽  
Linear Dependence ◽  
Ph Dependence ◽  
Order Rate Constant ◽  
X Ray Diffraction ◽  
X Ray ◽  
First Order ◽  
Oxidant Concentration ◽  
Ph Range ◽  
Kinetics Of

Oxidation of Ni2+,aq, by S2O82- to nickel(IV) in the presence of molybdate ion, as in the analogous manganese system, involves the formation of the soluble heteropolymolybdate anion [MMogO32]2- (M = Ni, Mn ). The nickel(IV) product crystallized as (NH4)6 [NiMogO32].6H2O from the reaction mixture in the rhombohedra1 space group R3, a 15.922(1), c 12.406(1) � ; the structure was determined by X-ray diffraction methods, and refined to a residual of 0.025 for 1741 independent 'observed' reflections. The kinetics of the oxidation were examined at 80 C over the pH range 3.0-5.2; a linear dependence on [S2O82-] and a non-linear dependence on l/[H+] were observed. The influence of variation of the Ni/Mo ratio between 1:10 and 1:25 on the observed rate constant was very small at pH 4.5, a result supporting the view that the precursor exists as the known [NiMo6O24H6]4- or a close analogue in solution. The pH dependence of the observed rate constant at a fixed oxidant concentration (0.025 mol dm-3) fits dequately to the expression kobs = kH [H+]/(Ka+[H+]) where kH = 0.0013 dm3 mol-1 s-1 and Ka = 4-0x10-5. The first-order dependence on peroxodisulfate subsequently yields a second-order rate constant of 0.042 dm3 mol-1 s-1. Under analogous conditions, oxidation of manganese(II) occurs eightfold more slowly than oxidation of nickel(II), whereas oxidation of manganese(II) by peroxomonosulfuric acid is 16-fold faster than oxidation by peroxodisulfate under similar conditions.

Kinetics of reconstitution of apotyrosinase by copper

1990 ◽  
Vol 68 (2) ◽  
pp. 476-479
Author(s):  
Donald C. Wigfield ◽  
Douglas M. Goltz
Keyword(s):  
Rate Constant ◽  
Copper Concentration ◽  
Copper Ions ◽  
Copper Ion ◽  
Order Rate Constant ◽  
First Order ◽  
Order Rate ◽  
Pseudo First Order ◽  
Rate Limiting ◽  
Kinetics Of

The kinetics of the reconstitution reaction of apotyrosinase with copper (II) ions are reported. The reaction is pseudo first order with respect to apoenzyme and the values of these pseudo first order rate constants are reported as a function of copper (II) concentration. Two copper ions bind to apoenzyme, and if the second one is rate limiting, the kinetically relevant copper concentration is the copper originally added minus the amount used in binding the first copper ion to enzyme. This modified copper concentration is linearly related to the magnitude of the pseudo first order rate constant, up to a copper concentration of 1.25 × 10−4 M (10-fold excess), giving a second order rate constant of 7.67 × 102 ± 0.93 × 102 M−1∙s−1.Key words: apotyrosinase, copper, tyrosinase.

Kinetics and mechanism of aminolysis of (Z)-4-arylidene-2-phenyl-5(4H)oxazolones

1992 ◽  
Vol 70 (10) ◽  
pp. 2515-2519 ◽  
Author(s):  
Sharifa S. Alkaabi ◽  
Ahmad S. Shawali
Keyword(s):  
Rate Constants ◽  
Activation Parameters ◽  
Order Conditions ◽  
Kinetics And Mechanism ◽  
Hammett Equation ◽  
Third Order ◽  
First Order ◽  
Different Temperatures ◽  
Pseudo First Order ◽  
Kinetics Of

The kinetics of the reactions of a series of (Z)-4-arylidene-2-phenyl-5(4H)oxazolones 1 with n-butylamine and piperidine were studied spectrophotometrically in dioxane, ethanol, and cyclohexane under pseudo-first-order conditions and at different temperatures. The relation k1(obs) = k2[amine] + k3[amine]2 was found applicable for all reactions studied in either dioxane or ethanol. However, in cyclohexane the n-butylaminolysis of 1 followed only third-order kinetics k1(obs) = k3[n-BuNH2]2. The kinetics of the reaction of 1 with n-butylamine in the presence of catalytic amounts of triethylamine in dioxane followed the equation: k1(obs)k2 = [n-BuNH2] + k3[n-BuNH2]2[Formula: see text] [Et3N]. The rate constants k2 and k3 correlated well with the Hammett equation and the corresponding activation parameters were determined. The results were interpreted in terms of a mechanism involving solvent- and amine-catalyzed processes.

Kinetics of Reactions of 8-Quinolinol and Acetate with Hydroxyaluminum Species in Aqueous Solutions. 1. Polynuclear Hydroxyaluminum Cations

1971 ◽  
Vol 49 (10) ◽  
pp. 1683-1687 ◽  
Author(s):  
R. C. Turner ◽  
Wan Sulaiman
Keyword(s):  
Acetic Acid ◽  
Rate Constant ◽  
Empirical Equation ◽  
Decomposition Reaction ◽  
Order Rate Constant ◽  
Acetate Concentration ◽  
First Order ◽  
Order Rate ◽  
Pseudo First Order ◽  
Kinetics Of

The effect of varying 8-quinolinol and acetate concentration on the rate of decomposition of poly-nuclear hydroxyaluminum cations was studied. It was found that the concentration of the undissociated 8-quinolinol and acetic acid molecules determined the magnitude of the first order rate constant for the decomposition of the polynuclear hydroxyaluminum cations, except when the acetate concentrations were relatively high. With high acetate concentrations, it appeared that polynuclear acetate species were involved in the reactions. An empirical equation was developed showing the effect of 8-quinolinol and acetic acid molecule concentrations on the pseudo first order rate constant for the decomposition reaction.

scholarly journals Kinetics of Oxidation of Tryptophan by Sodium Hypochlorite

1981 ◽  
Vol 36 (3) ◽  
pp. 359-361 ◽  
Author(s):  
Thomas Rausch ◽  
Frieder Hofmann ◽  
Willy Hilgenberg
Keyword(s):  
Activation Energy ◽  
Reaction Mechanism ◽  
Sodium Hypochlorite ◽  
Arrhenius Plot ◽  
Ph Dependence ◽  
Order Conditions ◽  
Kinetics Of Oxidation ◽  
First Order ◽  
Pseudo First Order ◽  
Kinetics Of

AbstractThe oxidation of tryptophan to 3-indoleacetaldehyde with sodium hypochlorite was investigated with 14C labelled DL-tryptophan. The reaction was performed under pseudo first order conditions. From the pH dependence of the reaction it was concluded that only the unprotonated tryptophan is converted to the aldehyde. The activation energy is 35 ± 2.2 (SE) kJ x mol-1 as derived from the Arrhenius plot. Variing the pH between 8.5 and 11.0 and the temperature in the range from 298 K to 318 K did not alter the selectivity of the reaction as confirmed by TLC of the product (purity ≧ 90%). A possible reaction mechanism is proposed.

Kinetics and mechanism of dehydrochlorination of N-aryl-C-ethoxycarbonylformohydrazidoyl chlorides

1986 ◽  
Vol 64 (5) ◽  
pp. 871-875 ◽  
Author(s):  
Ahmad S. Shawali ◽  
Hassan A. Albar
Keyword(s):  
Rate Constants ◽  
Water Solution ◽  
Chloride Ion ◽  
Order Conditions ◽  
Rate Law ◽  
First Order ◽  
Rate Determining Step ◽  
Pseudo First Order ◽  
Reaction Constants ◽  
Kinetics Of

The kinetics of triethylamine (TEA) catalyzed deydrochlorination of a series of N-aryl-C-ethoxycarbonylformohydrazidoyl chlorides 1a–m have been studied under pseudo-first-order conditions in 4:1 (v/v) dioxane–water solution at 30 °C. For all compounds studied, the kinetics followed the rate law: kobs = k2 (TEA). The values of the overall second-order rate constants for the studied compounds were correlated by the equation: log k2 = 0.533σ−-0.218. The results are compatible with a mechanism involving a fast reversible deprotonation step leading to the anion of 1, followed by rate-determining step involving the loss of the chloride ion from the anion. The reaction constants of these two steps were estimated to be 0.845 and −0.312, respectively.

The Rate constant of the Reaction of OH(A2Σ+) with H2O2(X˜1A)

2001 ◽  
Vol 215 (7) ◽  
Author(s):  
Walter Hack ◽  
R. Jordan
Keyword(s):  
Rate Constant ◽  
Room Temperature ◽  
Order Conditions ◽  
Oh Radicals ◽  
Quenching Rate ◽  
First Order ◽  
Electronically Excited State ◽  
Electronically Excited ◽  
Quenching Rate Constant ◽  
Pseudo First Order

The rate constant of the depletion of OH radicals in the first electronically excited state with hydrogenperoxid:OH(was determined at room temperature under pseudo first-order conditions [OH(The rate constant is:similar to the quenching rate constant of OH(

Evaluation of Chlorine for Inactivation of Bioterrorism Agents in Drinking Water

2013 ◽  
Vol 295-298 ◽  
pp. 599-603
Author(s):  
Feng Liu ◽  
Zhong Lin Chen ◽  
Sheng Chang
Keyword(s):  
Drinking Water ◽  
Free Chlorine ◽  
Inactivation Kinetics ◽  
Lag Phase ◽  
Solution Ph ◽  
First Order ◽  
Pseudo First Order ◽  
Ph Range ◽  
Kinetics Of ◽  
Experimental Temperature Range

The object of this paper is to measure the characteristics of the inactivation kinetics of B. subtilis spores-surrogates for B. anthracis spores following the treatment with free chlorine. The results indicated that the inactivation kinetics of B. subtilis spores with free chlorine was characterized by a lag phase followed by a pseudo-first-order rate of inactivation. The magnitude of the lag phase increased and the rate of subsequent inactivation decreased with the decreasing temperature, for the experimental temperature range of 1-30 °C. The same tendency of inactivation kinetics curves was observed for the increasing solution pH, for the experimental pH range of 6-8. The CT concept was proved to be valid for the inactivation kinetics of B. subtilis spores with free chlorine under the conditions investigated. The validity of B. subtilis spores served as conservative surrogates for B. anthracis spore has been finally discussed.

Sign in / Sign up

Export Citation Format

Share Document