Kinetics and Mechanism of Ligand Substitutionin Triglycinatovanadium(III) by EDTA and NTA in Aqueous Solutions

1994 ◽  
Vol 59 (5) ◽  
pp. 1077-1085
Author(s):  
Yasuhisa Ikeda ◽  
Refat M. Hassan ◽  
Moustafa M. Abd El-Fattah ◽  
Yul Y. Park ◽  
Hiroshi Tomiyasu
Keyword(s):  
Ionic Strength ◽  
Aqueous Solutions ◽  
Kinetic Parameters ◽  
Ligand Substitution ◽  
Reactive Species ◽  
Constant Ionic Strength ◽  
Substitution Reactions ◽  
First Order ◽  
Kinetics Of ◽  
Mechanism Of The Reaction

The kinetics of ligand substitution reactions in triglycinatovanadium(III) by EDTA and NTA as multidentate ligands were investigated at a constant ionic strength of 2.5 mol dm-3 spectrophotometrically. The substitutions were second-order reactions, first order in both reactants. Their rate could be expressed in the form r = k [V(gly)3] [EDTA(NTA)] where k = 2.62 .10-2 and 6.96 .10-2 mol-1 dm3 s-1 at 25 °C for EDTA and NTA, respectively. The results obtained at different pH indicated that [H2edta]2- and [Hnta]2- ions were the most reactive species in the substitution. Kinetic parameters have been evaluated and a tentative mechanism of the reaction has been proposed.

The Kinetics of Water Exchange on Aqueous Aquapentacyanocobaltate(III)

1988 ◽  
Vol 41 (9) ◽  
pp. 1323 ◽  
Author(s):  
SM Bradley ◽  
H Doine ◽  
HR Krouse ◽  
MJ Sisley ◽  
TW Swaddle
Keyword(s):  
Ionic Strength ◽  
Water Exchange ◽  
Ligand Substitution ◽  
Mean Value ◽  
Order Kinetic ◽  
Substitution Reactions ◽  
First Order ◽  
Solvent Water ◽  
Temperature And Pressure ◽  
Kinetics Of

The temperature and pressure dependences of the rate of exchange of oxygen-18 between labelled Co(CN)5OH22- and solvent water at pH 3 and ionic strength 0.35 mol l-1 are governed by the following first-order kinetic parameters: kex = 5.8x10-4 s-1 at 298 K; ΔH‡ = 90.2 kJ mol-1; ΔS‡ = -4 J K-1 mol-1; and ΔV‡ = + 7 cm3 mol-1 (mean value, 0-400 MPa ). Although these results are indicative of a strongly dissociative mode of activation, the rate of water exchange is about twice that predicted by previous workers on the basis of a limiting dissociative (D or SN1 lim ) mechanism for the replacement of water in Co(CN)5OH22- by other ligands . This implies that the purported intermediate Co(CN)52- cannot be long-lived on the time scale of relaxation of the second coordination sphere, and supports the contention of Burnett and coworkers that the mechanism of this textbook example of a series of dissociatively activated ligand substitution reactions is properly classified as dissociative interchange (Id).

Kinetics and Mechanism of Hexachloroiridate(IV) Oxidation of Arsenic(III) in Acidic Perchlorate Solutions

1992 ◽  
Vol 57 (7) ◽  
pp. 1451-1458 ◽  
Author(s):  
Refat M. Hassan
Keyword(s):  
Ionic Strength ◽  
Fractional Order ◽  
Activation Parameters ◽  
Order Reaction ◽  
First Order Reaction ◽  
Intermediate Complex ◽  
Constant Ionic Strength ◽  
Kinetics Of Oxidation ◽  
First Order ◽  
Kinetics Of

The kinetics of oxidation of arsenic(III) by hexachloroiridate(IV) at lower acid concentrations and at constant ionic strength of 1.0 mol dm-3 have been investigated spectrophotometrically. A first-order reaction in [IrCl62-] and fractional order with respect to arsenic(III) have been observed. A kinetic evidence for the formation of an intermediate complex between the hydrolyzed arsenic(III) species and the oxidant was presented. The results showed that decreasing the [H+] is accompanied by an appreciable acceleration of the rate of oxidation. The activation parameters have been evaluated and a mechanism consistent with the kinetic results was suggested.

scholarly journals Kinetics of gibbsite leaching in sodium hydroxide aqueous solution

2002 ◽  
Vol 56 (9) ◽  
pp. 381-385
Author(s):  
Ljubica Pavlovic ◽  
Zagorka Acimovic-Pavlovic ◽  
Ljubisa Andric ◽  
Aurel Prstic
Keyword(s):  
Activation Energy ◽  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Sodium Hydroxide ◽  
Kinetic Parameters ◽  
Rate Constant ◽  
Reaction Rate ◽  
Reaction Rate Constant ◽  
Kinetics Of ◽  
Mechanism Of The Reaction

In order to study the kinetics and mechanism of the reaction, laboratory leaching was carried out with industrially produced gibbsite ?-Al(OH)3 in aqueous solutions containing an excess of sodium hydroxide. The results obtained reaction temperature, duration and base concentration varied. The basic kinetic parameters were determined from: the reaction rate constant k=8.72?107 exp (-74990/RT) and the process activation energy in the range Ea=72.5-96.81 kJ/mol.

scholarly journals Cinétique de la formation de la métalloporphyrine Cu(II) – hématoporphyrine IX dans l'acide acétique aqueux

1975 ◽  
Vol 53 (16) ◽  
pp. 2375-2380 ◽  
Author(s):  
Guy Paquette ◽  
Miklos Zador
Keyword(s):  
Acetic Acid ◽  
Reactive Species ◽  
Acid Water ◽  
First Order ◽  
Water Solvent ◽  
Acetic Acid Water ◽  
Kinetics Of ◽  
Hematoporphyrin Ix ◽  
Mechanism Of The Reaction

The kinetics of interaction of hematoporphyrin IX with Cu(II) has been studied in an acetic acid – water solvent (50%–50% v/v). The reaction is of first order with respect to the porphyrin whereas the order with respect to copper(II) perchlorate is smaller than one. This is explained by taking into account the interaction between Cu2+ and acetic acid. The reactive species are Cu2+, CuOAc+, and free porphyrin. The mechanism of the reaction is compared to those proposed for similar systems.

Thallic Ion Oxidation of Styrene: Kinetics of Decomposition of the Oxythallation Adduct C6H5—CH(OCH3)—CH2Tl(OAc)2

1974 ◽  
Vol 52 (15) ◽  
pp. 2667-2672 ◽  
Author(s):  
Louise Nadon ◽  
Miklos Zador
Keyword(s):  
Kinetic Parameters ◽  
Reactive Species ◽  
Rate Law ◽  
First Order ◽  
Order Rate ◽  
Rate Determining Step ◽  
Kinetics Of Decomposition ◽  
Low Concentrations ◽  
Kinetics Of

The kinetics of decomposition of the organo-thallic adduct formed in methanol between styrene and Tl(OAc)3, (C6H5—CH(OCH3)—CH2—Tl(OAc)2) has been studied in a water–methanol solvent. The reaction follows a first order rate law. The organo-thallic compound, RTl(OAc)2, is shown to be dissociated at low concentrations yielding two reactive species, RTlOH+ and RTl2+. The influence of acidity on the rate of decomposition shows that RTl2+ is much more reactive than RTiOH+. The kinetic parameters have been determined. The implication of the results on the rate-determining step of Tl(III) oxidation of styrene is discussed.

Ligand substitution reaction on a platinum(ii) complex with bio-relevant thiols: kinetics, mechanism and bioactivity in aqueous medium

RSC Advances ◽  
2014 ◽  
Vol 4 (82) ◽  
pp. 43516-43524 ◽  
Author(s):  
Avradeep Samanta ◽  
Goutam Kr. Ghosh ◽  
Ishani Mitra ◽  
Subhajit Mukherjee ◽  
Jagadeesh C. Bose K ◽  
...  
Keyword(s):  
Ionic Strength ◽  
Aqueous Medium ◽  
Substitution Reaction ◽  
Ligand Substitution ◽  
Constant Ionic Strength ◽  
Kinetics Of ◽  
Ligand Substitution Reaction

Kinetics of the interaction between [Pt(pic)(H2O)2](ClO4)2and selected thiols has been studied in aqueous medium as a function of [complex], [thiol], pH and temperature at constant ionic strength.

scholarly journals Kinetic Study of Aluminum Sulphate and Ammonium Aluminum Sulphate Coagulants in Wastewater Treatment

2007 ◽  
Vol 3 (3) ◽  
pp. 222-228
Author(s):  
Lugard Ukiwe ◽  
C.I.A. Nwoko ◽  
Okere-Chijioke M
Keyword(s):  
Wastewater Treatment ◽  
Kinetic Study ◽  
Kinetic Parameters ◽  
Rate Constant ◽  
General Trend ◽  
First Order ◽  
Coagulation Performance ◽  
Aluminum Sulphate ◽  
Kinetics Of ◽  
Mechanism Of The Reaction

An investigation into the kinetics of two inorganic coagulant namely: aluminum sulphate octadecahydrate (Al2(SO4)3.18H2O) an ammonium aluminum sulphate dodecahydrate (NH4Al(SO4)2.12H2O) was studied to determine the effect of certain kinetic parameters on coagulation performance of the above mentioned coagulants. Results of analysis obtained revealed that the rate constant (k) for Al2(SO4)3.18H2O was 5.727s-1, while that for NH4Al(SO4)2.12H2O was 2.282s-1. However, the order of the reaction (xn) of Al2(SO4)3.18H2O and NH4Al(SO4)2.12H2O with the wastewater was 1.0 and 1.0, respectively, indicating that both reactions were first order. Considering the mechanism of the reaction, the general trend observed indicated that the Al2(SO4)3.18H2O reaction was thrice as fast as the NH4Al(SO4)2.12H2O reaction. This fact together with the larger value of k for Al2(SO4)3.18H2O obtained in the experiment lend credence to the widely held believe that Al2(SO4)3.18H2O is a more effective coagulant than NH4Al(SO4)2.12H2O in wastewater treatment.

Kinetics and mechanism of oxidation of Chitosan Polysaccharide by Permanganate Ion in Aqueous Perchlorate Solutions

2003 ◽  
Vol 2003 (4) ◽  
pp. 182-183 ◽  
Author(s):  
Gamal Abdel-Whab Ahmed ◽  
Khalid Suliman Khairou ◽  
Refat Moustafa Hassan
Keyword(s):  
Ionic Strength ◽  
Second Order ◽  
Kinetics And Mechanism ◽  
Constant Ionic Strength ◽  
Kinetics Of Oxidation ◽  
First Order ◽  
Mechanism Of Oxidation ◽  
Kinetics Of ◽  
Overall Kinetics ◽  
Permanganate Ion

The kinetics of oxidation of chitosan as polysaccharide by permanganate in aqueous perchlorate media at a constant ionic strength was found to have second-order overall kinetics and to be first-order in the concentration of both reactants, the results obtained showed that the reaction is acid catalysed.

Evidence for general base catalysis by protic solvents in a kinetic study of alcoholyses and hydrolyses of 1-(phenoxycarbonyl)pyridinium ions under both solvolytic and non-solvolytic conditions

2009 ◽  
Vol 74 (1) ◽  
pp. 43-55 ◽  
Author(s):  
Dennis N. Kevill ◽  
Byoung-Chun Park ◽  
Jin Burm Kyong
Keyword(s):  
Second Order ◽  
Base Catalysis ◽  
Substitution Reactions ◽  
Third Order ◽  
Methoxy Derivative ◽  
First Order ◽  
General Base ◽  
Protic Solvents ◽  
Kinetics Of ◽  
Pyridinium Ions

The kinetics of nucleophilic substitution reactions of 1-(phenoxycarbonyl)pyridinium ions, prepared with the essentially non-nucleophilic/non-basic fluoroborate as the counterion, have been studied using up to 1.60 M methanol in acetonitrile as solvent and under solvolytic conditions in 2,2,2-trifluoroethan-1-ol (TFE) and its mixtures with water. Under the non- solvolytic conditions, the parent and three pyridine-ring-substituted derivatives were studied. Both second-order (first-order in methanol) and third-order (second-order in methanol) kinetic contributions were observed. In the solvolysis studies, since solvent ionizing power values were almost constant over the range of aqueous TFE studied, a Grunwald–Winstein equation treatment of the specific rates of solvolysis for the parent and the 4-methoxy derivative could be carried out in terms of variations in solvent nucleophilicity, and an appreciable sensitivity to changes in solvent nucleophilicity was found.

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