Kinetics and mechanisms of oxidations by metal ions. Part VIII. Oxidation of n-propanol by aquomanganese(III) ions

1987 ◽  
Vol 65 (2) ◽  
pp. 277-281 ◽  
Author(s):  
Mahendra Mehta ◽  
Ratan R. Nagori ◽  
Raj N. Mehrotra
Keyword(s):  
Ionic Strength ◽  
Metal Ions ◽  
Equilibrium Constant ◽  
Thermodynamic Parameters ◽  
The Other ◽  
Constant Ionic Strength ◽  
Rate Law

The oxidation of n-propanol by aquomanganese(III) ions in perchlorate medium of constant ionic strength (4 mol dm−3, NaClO4) is described by the rate law [i] which is based on the consideration of the reactions [ii]–[ix].[Formula: see text]A further analysis of the rate law in terms of the results indicated that MnOH2+ (aq) is the major oxidant. The values of the equilibrium constant (β1) and rate determining constant (k1) are reported together with the associated thermodynamic parameters. The values of the other constants, k, Ka, and β, could not be determined though an assumption was made that β ≈ β1.

Substitution reactions on arsenic(V). The formation and hydrolysis of pentaamminearsenatocobalt(III) in aqueous solution

1973 ◽  
Vol 26 (9) ◽  
pp. 1877 ◽  
Author(s):  
TA Beech ◽  
NC Lawrence ◽  
SF Lincoln
Keyword(s):  
Aqueous Solution ◽  
Ionic Strength ◽  
Bond Formation ◽  
The Other ◽  
Substitution Reactions ◽  
Rate Law ◽  
Hydrolysis Of ◽  
Hydrolysis Reactions

The formation of Co(NH3)5HAsO4+ and Co(NH3)5H2AsO42+ conforms to the rate law: ����������� rate = [Co(NH3)5H2O3+](k-1[HAsO42-]+k-2[H2AsO4-]) where k-1 = (11�1)x10-2 l. mol-1 s-1 and k-2 = (120�15)x10-4 l. mol-1 s-1 at 295 K and unit ionic strength. The hydrolysis of the arsenato complex conforms to the rate law: ������ rate = [total arsenato complex](Ka2k1+k2[H+]+k3[H+]2)(Ka2+[H+])-1 where k1 = (290�15)x10-7s-1, k2 = (408�20)x 10-6 s-1, k3 = (670�34)x10-3 l. mol-1 s-1, and pKa2 = 3.30�0.05 at 295 K and unit ionic strength. The formation and hydrolysis reactions proceed through bond formation and cleavage between oxygen and arsenic. The mechanisms of the reactions characterized by k1 and k-1 are considered to be associative substitutions on arsenic(v), but the mechanisms of the other reactions are less certain.

Alginate Polyelectrolyte Ionotropic Gels-XVI. Kinetics and Chemical Equilibria Studies for Heterogeneous Ion Exchange of Polyvalent Metal Ions in Alginate Gel Complexes

1992 ◽  
Vol 4 (3) ◽  
pp. 173-179 ◽  
Author(s):  
S. A. El-Shatoury ◽  
R. M. Hassan ◽  
A. A. Said
Keyword(s):  
Ionic Strength ◽  
Ion Exchange ◽  
Metal Ions ◽  
Thermodynamic Parameters ◽  
Coordination Geometry ◽  
Ionic Radii ◽  
Chemical Equilibria ◽  
Polyvalent Metal ◽  
Alginate Gel ◽  
Counter Ions

The kinetics or chemical equilibria of exchange of Ca(II), Sr(II), Ba(I), Zn(II), Cd(II), Al(III), Fe(III), Se(IV), Ce(IV) and Th(IV) counter ions in alginate gel complexes by H+ ions have been investigated titrimetrically and conductimetrically at a constant ionic strength of 0.1 mol/dm3. The thermodynamic parameters have been evaluated and are discussed in terms of ionic radii and polarizability of the metal ions, coordination geometry, and stability of the gel complexes.

Pitzer and Thermodynamic Parameters of Triethanolamine and Glycine in Aqueous Saline Solutions

1993 ◽  
Vol 58 (6) ◽  
pp. 1269-1278 ◽  
Author(s):  
Roberto Herrero ◽  
Isabel Brandariz ◽  
Sarah Fiol ◽  
Manuel Sastre de Vicente
Keyword(s):  
Ionic Strength ◽  
Aqueous Solutions ◽  
Equilibrium Constant ◽  
Thermodynamic Parameters ◽  
Thermodynamic Quantities ◽  
Pitzer Equations ◽  
Ionic Interaction ◽  
Ionic Strength Dependence ◽  
Strength Dependence ◽  
Saline Solutions

On the basis of the ionic strength dependence of the equilibrium constant (pK*) of thriethanolamine (TEA) and glycine, the ionic interaction parameters of the species involved in the equilibria TEAH+ ↔ TEA + H+ (for TEA), AH2+ ↔ AH + H+ and AH ↔ A- + H+ (for glycine) in aqueous solutions of KCl and KNO3, respectively, were determined using the Pitzer equations. Values of pK* were expressed on both the molarity and the molality scale at various temperatures and values of thermodynamic quantities ∆G0, ∆H0 and ∆S0 ascertained, for TEA.

EFFECT OF CHANGING pH UPON THE RATE AND MECHANISM OF DECARBOXYLATION OF SUBSTITUTED ANTHRANILIC ACIDS

1965 ◽  
Vol 43 (11) ◽  
pp. 3080-3094 ◽  
Author(s):  
G. E. Dunn ◽  
P. Leggate ◽  
I. E. Scheffler
Keyword(s):  
Ionic Strength ◽  
Aromatic Ring ◽  
Maximum Rate ◽  
The Other ◽  
Constant Ionic Strength ◽  
Ionization Constants ◽  
Anthranilic Acids ◽  
Isoelectric Ph

The ionization constants of 4-methoxyanthranilic acid have been determined spectrophotometrically in water at 60 °C and ionic strength 0.10. The variation in rate of decarboxylation with varying pH at constant ionic strength has been measured at 90 °C with 4-methylanthranilic acid and at 60 °C with 4-methoxyanthranilic acid. With each acid the maximum rate occurs at a pH about 2 units less than the isoelectric pH. To account for these results it is necessary to postulate an equilibrium between at least two intermediates formed by protonation of the 1-position of the aromatic ring. One of these must be formed from the anion and the other(s) by protonation of neutral acid and (or) zwitterion.

Kinetics of oxidation of nitrite by hypochlorite ions in aqueous basic solution

1976 ◽  
Vol 54 (21) ◽  
pp. 3401-3406 ◽  
Author(s):  
J. M. Cachaza ◽  
J. Casado ◽  
A. Castro ◽  
M. A. López Quintela
Keyword(s):  
Ionic Strength ◽  
Initial Step ◽  
Activation Energies ◽  
The Other ◽  
Basic Solution ◽  
Unimolecular Decomposition ◽  
Kinetics Of Oxidation ◽  
Rate Law ◽  
Kinetics Of

The kinetics of oxidation of nitrite to nitrate by hypochlorite ions in aqueous basic solution [Formula: see text] have been studied using a dynamic spectrophotometric technique. The rate law is[Formula: see text]At 298.0 K and ionic strength 0.40 M, d = (3.4 ± 0.2) × 10−8 mol l−1 s−1 and e = (2.8 ± 0.2) × 10−6 s−1. The associated activation energies are 56 ± 3 and 61 ± 3 kJ mol−1 respectively. A mechanism is proposed involving the reversible initial step:[Formula: see text]with the NO2Cl undergoing two parallel subsequent reactions, one a unimolecular decomposition and the other an attack by NO2− on NO2Cl.

Equilibrium constants of pyridoxal 5'-phosphate Schiff bases - A polarographic study

1983 ◽  
Vol 48 (7) ◽  
pp. 1950-1955 ◽  
Author(s):  
Juan Llor ◽  
Javier Bonal ◽  
Manuel Cortijo
Keyword(s):  
Schiff Base ◽  
Ionic Strength ◽  
Equilibrium Constant ◽  
Schiff Bases ◽  
Ph Dependence ◽  
Equilibrium Constants ◽  
Constant Ionic Strength ◽  
Polarographic Study ◽  
Ionic Forms

The equilibrium constant for the formation of the Schiff base between pyridoxal 5'-phosphate and n-hexylamine has been evaluated from polarographic measurements. The pH dependence of the equilibrium constant has been investigated at constant ionic strength. The values thus obtained for the equilibrium constant compare well with those computed from the pK of the several ionic forms of pyridoxal 5'-phosphate, its Schiff base and the amine present in the solution.

scholarly journals The nature of the slow metal ion-dependent conformational transition in bovine prothrombin

1979 ◽  
Vol 183 (3) ◽  
pp. 513-517 ◽  
Author(s):  
H C Marsh ◽  
M E Scott ◽  
R G Hiskey ◽  
K A Koehler
Keyword(s):  
Fluorescence Quenching ◽  
Metal Ions ◽  
Kinetic Parameters ◽  
Equilibrium Constant ◽  
Rate Constants ◽  
Metal Ion ◽  
Conformational Transition ◽  
The Other ◽  
Proline Residue ◽  
Structural Isomerization

Kinetic parameters characterizing the slow structural isomerization observed via metal ion-dependent intrinsic fluorescence quenching of bovine prothrombin Fragment 1 have been determined. From forward and reverse rate constants, an equilibrium constant of approx. 0.25 is calculated. This result is consistent with the hypothesis that there exists, in the absence of metal ions, an equilibrium between two forms of bovine Fragment 1, one of which can interact rapidly with Ca2+ and subsequently with phospholipid. The other form of Fragment 1 cannot interact with Ca2+ in a manner that yields a phospholipid-binding form of the protein. Interconversion of these two forms of Fragment 1 occurs and may involve the isomerization of a proline residue.

Effets des cations alcalins et pseudo-alcalins sur quelques équilibres et en particulier sur l'équilibre d'extraction de l'acide thiocyanique par la méthylisobutylcétone

1976 ◽  
Vol 54 (1) ◽  
pp. 19-23
Author(s):  
Louise Schriver
Keyword(s):  
Ionic Strength ◽  
Equilibrium Constant ◽  
Aqueous Phase ◽  
Association Constant ◽  
Ion Pairs ◽  
Constant Ionic Strength ◽  
Thiocyanic Acid ◽  
Alkaline Cations ◽  
Methylisobutyl Ketone

The equilibrium constant for the extraction of thiocyanic acid by methylisobutyl ketone at constant ionic strength, depends on the nature of alkaline cations present in the aqueous phase. The phenomenon could be explained by the existence of ion pairs for which the association constant Kp is derivable. However the extraction of chlorpromazinium thiocyanate by the same solvent and the formation of the monothiocyanate complex of zirconium in aqueous phase are both independent of the nature of the electrolyte. The observed variations for the extraction of thiocyanic acid which exist also for the extraction of hydrochloric and perchloric acids by methylisobutyl ketone, result from the variation of species activities with a change in the identity of the cations.

Adsorption of chlorate and bromate ions on mercury electrodes from constant ionic strength solutions

1988 ◽  
Vol 85 ◽  
pp. 523-527
Author(s):  
M.M. Zuleika ◽  
Palhares SILVA ◽  
Ernesto Rafael GONZALEZ ◽  
Luis Alberto AVACA ◽  
Artur de Jesus MOTHEO
Keyword(s):  
Ionic Strength ◽  
Constant Ionic Strength ◽  
Mercury Electrodes
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