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.

The reaction between 2,2-di(4-nitrophenyl)1,1,1-trifluoroethane and tert-butoxide ion in tert-butyl alcohol solvent

1980 ◽  
Vol 58 (18) ◽  
pp. 1979-1982 ◽  
Author(s):  
Arnold Jarczewski ◽  
Kenneth T. Leffek
Keyword(s):  
Isotope Effects ◽  
Activation Parameters ◽  
Butyl Alcohol ◽  
Blue Colour ◽  
Butyl Ether ◽  
Tert Butyl ◽  
Kinetic Isotope ◽  
Tert Butyl Alcohol ◽  
Reaction Proceeds ◽  
Alcohol Solvent

The reaction between 2,2-di(4-nitrophenyl) 1,1,1-trifluoroethane and excess sodium tert-butoxide in tert-butyl alcohol takes place rapidly to yield first the olefin, by elimination of HF. This is followed by a slower addition of tert-butoxide to the olefin, which upon reaction with the solvent gives the tert-butyl ether as the final product. The blue anions involved in each of these reactions are observed.Rate constants, the primary deuterium kinetic isotope effects, and the activation parameters have been measured for the appearance of the initial blue colour and also for the formation of the olefin. It is concluded that the reaction proceeds by a reversible ElcB mechanism.

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