Solvolysis rates in aqueous–organic mixed solvents. III. Kinetics of the alkaline solvolysis of monochloroacetate ion in water – tert-butyl alcohol solutions

1976 ◽  
Vol 54 (11) ◽  
pp. 1687-1691 ◽  
Author(s):  
El-Hussieny M. Diefallah
Keyword(s):  
Mole Fraction ◽  
Mixed Solvents ◽  
Activation Parameters ◽  
Butyl Alcohol ◽  
Solvent Mixtures ◽  
First Order ◽  
Tert Butyl Alcohol ◽  
Rate Of Reaction ◽  
Aqueous Organic Mixed Solvents ◽  
Kinetics Of

The temperature dependence of the rate of alkaline solvolysis of monochloroacetate ion in water – tert-bulyl alcohol solutions has been determined. The rates of reaction were first order with respect to both the chloroacetate ion and to the total solvoxide ion concentrations. The reactivity is enhanced, first slowly, and then more rapidly, by increasing the concentration of tert-bulyl alcohol in the solvent mixtures. The rate of reaction increases with the reciprocal of the dielectric constant of the medium and the plot of log kvs. 1/D can best be represented by two lines intersecting at a point corresponding to 0.9 water mole fraction. The activation parameters ΔH*and ΔS* for the solvolysis reaction showed a minimum at about 0.9 water mole fraction. The significance of these results from the viewpoint of the electrostatic theory and the changing of solvent structure in such mixtures is discussed.

Solvolysis rates in aqueous – organic mixed solvents. V. Kinetics of the alkaline decarboxylation of trichloroacetate ion in water – ethanol solutions

1978 ◽  
Vol 56 (15) ◽  
pp. 2053-2057 ◽  
Author(s):  
El-Hussieny M. Diefallah ◽  
A. M. El-Nadi
Keyword(s):  
Mole Fraction ◽  
Pure Water ◽  
Mixed Solvents ◽  
Activation Parameters ◽  
Solvent Mixtures ◽  
Rate Of Reaction ◽  
Ethanol Addition ◽  
Regular Increase ◽  
Aqueous Organic Mixed Solvents ◽  
Kinetics Of

The kinetics of the alkaline decarboxylation of trichloroacetate ion in ethanol–water solutions have been studied over the temperature range 35.0 to 70.0 °C. The rate of reaction is first order with respect to the trichloroacetate ion and is independent of the concentration of the hydroxide ion. The reactivity is enhanced by increasing the concentration of ethanol in the water–ethanol solutions and the rate of reaction varies with ethanol addition in a nonlinear manner. The rate of reaction increases with the reciprocal of the dielectric constant of the medium and the plot of log k vs. 1/D is approximately linear for solvent mixtures with less than about 0.7 water mole fraction but is strongly curved towards the pure water end. The activation parameters for the reaction show a regular increase in the solvent composition range 0.3 to 1.0 water mole fraction. The results are discussed in terms of the influence of solvent internal pressure and polarity on reactivity and of the increased amount of hydrogen-bonded structure in the water-rich solutions.

Solvolysis rates in aqueous–organic mixed solvents. IX. Solvolysis of dichloroacetate ion in water–methanol solutions

1981 ◽  
Vol 59 (8) ◽  
pp. 1208-1211 ◽  
Author(s):  
El-Hussieny M. Diefallah ◽  
Mohamed A. Ashy ◽  
Ahmed O. Baghlaf
Keyword(s):  
Mole Fraction ◽  
Reaction Rate ◽  
Mixed Solvents ◽  
Activation Parameters ◽  
Solvent Structure ◽  
Temperature Range ◽  
Methanol Solutions ◽  
Aqueous Organic Mixed Solvents ◽  
Kinetics Of ◽  
Influence Of Solvent

The kinetics of the alkaline solvolysis of dichloroacetate ion in water–methanol solutions have been studied in the temperature range of 50.0 to 65.0 °C and the influence of solvent variation on reaction rate has been examined in terms of changes in the activation parameters. The activation parameters ΔH≠ and ΔS≠ for the solvolysis reaction showed a minimum at about 0.8 water mole fraction. The significance of the results was discussed in view of the electrostatic theory and the changing of solvent structure.

Thermodynamic and Kinetic Investigation of the Solvent Effect on the Oxidation of [Co(en)2SCH2COO]+ with S2O82- In Water-Methanol and Water-tert-Butyl Alcohol Mixtures

1993 ◽  
Vol 58 (5) ◽  
pp. 1001-1006 ◽  
Author(s):  
Oľga Vollárová ◽  
Ján Benko
Keyword(s):  
Transfer Functions ◽  
Activation Parameters ◽  
Butyl Alcohol ◽  
Oxidation Of Co ◽  
Kinetics Of Oxidation ◽  
Tert Butyl ◽  
Tert Butyl Alcohol ◽  
Alcohol Mixtures ◽  
Kinetics Of

The kinetics of oxidation of [Co(en)2SCH2COO]+ with S2O82- was studied in water-methanol and water-tert-butyl alcohol mixtures. Changes in the reaction activation parameters ∆H≠ and ∆S≠ with varying concentration of the co-solvent depend on the kind of the latter, which points to a significant role of salvation effects. The solvation effect on the reaction is discussed based on a comparison of the transfer functions ∆Ht0, ∆St0 and ∆Gt0 for the initial and transition states with the changes in the activation parameters accompanying changes in the CO-solvent concentration. The transfer enthalpies of the reactant were obtained from calorimetric measurements.

Kinetics of oxidation of bis(ethylenediamine)mercaptoacetatocobalt(III) and cysteinatobis(ethylenediamine)cobalt(III) ions by peroxodisulphate in aqueous-nonaqueous mixed solvents

1986 ◽  
Vol 51 (5) ◽  
pp. 1049-1060 ◽  
Author(s):  
Oľga Vollárová ◽  
Ján Benko ◽  
Ivana Matejeková
Keyword(s):  
Perchloric Acid ◽  
Transfer Functions ◽  
Mixed Solvents ◽  
Sodium Perchlorate ◽  
Activation Parameters ◽  
Solvent System ◽  
Butyl Alcohol ◽  
Complex Ions ◽  
Kinetics Of Oxidation ◽  
Kinetics Of

The kinetics of oxidation in the first step was studied for coordination-bonded sulphur in the cysteinatobis(ethylenediamine)cobalt(III) and bis(ethylenediamine)mercaptoacetatocobalt(III) ions using peroxodisulphate as oxidant. The effect of the acid-base equilibria of the reactants was established based on the dependences of the rate constant and the thermodynamic activation parameters ΔH and ΔS on perchloric acid concentration. The effect of ionic strength at various perchloric acid concentrations, was examined for the two complex ions. The combined effect of perchloric acid and sodium perchlorate was investigated in water-tert-butyl alcohol and water-ethylene glycol solutions. The transfer functions were calculated from the changes in the solubility of the reactants on passing from aqueous to the mixed aqueous-nonaqueous solutions, and the role of solvation during the oxidation of the complexes by peroxodisulphate was assessed based on the dependences of the transfer functions on the nonaqueous component content of the solvent system.

Kinetics of oxidation of the bis(ethylenediamine)mercaptoacetatocobalt(III) and cysteinato-bis(ethylenediamine)cobalt(III) ions by hydrogen peroxide in mixed aqueous-nonaqueous solutions

1988 ◽  
Vol 53 (3) ◽  
pp. 554-562
Author(s):  
Ján Benko ◽  
Oľga Vollárová ◽  
Miroslav Kovarčík
Keyword(s):  
Hydrogen Peroxide ◽  
Reaction Rate ◽  
Activation Parameters ◽  
Butyl Alcohol ◽  
Acid Base ◽  
Kinetics Of Oxidation ◽  
Tert Butyl Alcohol ◽  
Alcohol Water ◽  
Acid Base Equilibrium ◽  
Kinetics Of

The kinetics of oxidation of the coordinatively bonded sulphur in the cysteinato-bis(ethylenediamine)cobalt(III) and bis(ethylenediamine)mercaptoacetatocobalt(III) complexes by hydrogen peroxide to the sulphoxides was examined in HClO4 solutions (c(HClO4) = 1 – 500 mmol l-1) with a view to obtaining data characterizing the effect of the acid-base equilibria of the reactants on the reaction rate. The reaction rate was found affected particularly by the acid-base equilibrium of the oxidant, which plays a role in strongly acid solutions. The oxidation was also studied in water-methyl alcohol, water-tert-butyl alcohol and water-ethylene glycol mixtures, and the effect of the mole fraction of the nonaqueous component on the rate constant and thermodynamic activation parameters was examined.

Kinetics of aquation of bromopentaamminechromium(III) and bromopentaamminecobalt(III) ions in water-alcohol solvents

1979 ◽  
Vol 44 (2) ◽  
pp. 495-501 ◽  
Author(s):  
Vladislav Holba ◽  
Oľga Grančičová
Keyword(s):  
Reaction Kinetics ◽  
Rate Constants ◽  
Compensation Effect ◽  
Activation Parameters ◽  
Butyl Alcohol ◽  
Isokinetic Temperature ◽  
Tert Butyl Alcohol ◽  
Alcohol Solvents ◽  
Kinetics Of ◽  
Water Alcohol

The rate constants and activation parameters of aquation of bromopentaamminechromium(III) and bromopentaamminecobalt(III) ions were determined in mixtures of water with methanol, ethanol, 2-propanol, and tert-butyl alcohol. A compensation effect was observed in the first three mixtures and the isokinetic temperature was determined. The rate constant were correlated with the ionizing strength of the solvent. The influence of interactions between the water and alcohol molecules on the reaction kinetics is discussed.

Kinetics of alkaline hydrolysis of 3,4-thiophenedicarboxylic acid monomethyl ester in aqueous-nonaqueous media

1988 ◽  
Vol 53 (6) ◽  
pp. 1268-1273
Author(s):  
Ján Benko ◽  
Oľga Vollárová
Keyword(s):  
Methyl Alcohol ◽  
Alkaline Hydrolysis ◽  
Mixed Solvents ◽  
Activation Parameters ◽  
Butyl Alcohol ◽  
Nonaqueous Media ◽  
Alcohol Water ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
Monomethyl Ester

The kinetics of alkaline hydrolysis of 3,4-thiophenedicarboxylic acid monomethyl ester has been studied in mixed solvents water-methyl alcohol, water-tert-butyl alcohol, and water-dioxane. The specific effects causing different courses of these dependences have been evaluated. The greatest changes in the thermodynamic activation parameters have been observed in the medium of water-methyl alcohol.

Influence of solvent on kinetics of reactions of Cr(II) ions

1981 ◽  
Vol 46 (7) ◽  
pp. 1554-1559 ◽  
Author(s):  
Peter Ševčík ◽  
Ján Tkáč
Keyword(s):  
Mole Fraction ◽  
Methyl Alcohol ◽  
Maleic Acid ◽  
Redox Reaction ◽  
Isopropyl Alcohol ◽  
Butyl Alcohol ◽  
Dichloroacetic Acid ◽  
Tert Butyl ◽  
Tert Butyl Alcohol ◽  
Kinetics Of

This paper deals with the study of redox reactions of Cr(II) ions with hydroxylamine, hydrazoic acid, maleic acid, di- and trichloroacetic acids in so-called typically aqueous mixtures of water with methyl alcohol, isopropyl alcohol, or tert-butyl alcohol. The kinetics of the redox reaction with dichloroacetic acid was studied also in the medium of aqueous acetone and in a typically nonaqueous medium water-acetonitrile. The dependences of activation Gibbs energies on the mole fraction of the nonaqueous component have no minima and maxima characteristic for the thermodynamic behaviour of the mentioned binary systems. However, the change of the activation Gibbs energy with the mole fraction of tert-butyl alcohol is not monotonous with all the studied reactions of Cr(II) ions. At a constant mole fraction of the nonaqueous component, the usual trend of the influence on the rate constants decreases in the sequence tert-butyl alcohol > isopropyl alcohol > methyl alcohol. Tert-butyl alcohol hinders most strongly the redox reaction with trichloroacetic acid, whereas it accelerates the reaction of Cr(II) ions with maleic acid and hydroxylamine.

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