Individual extraction constants of some dicarbollylcobaltate anions in the water-nitrobenzene system

1995 ◽  
Vol 198 (2) ◽  
pp. 359-365 ◽  
Author(s):  
E. Makrlík ◽  
J. Rais ◽  
K. Baše ◽  
J. Plešek ◽  
P. Vaňura
Keyword(s):  
Extraction Constants ◽  
Individual Extraction Constants

The Extraction of Strontium and Barium with a Solution of Bis-1,2-Dicarbollylcobaltate in Nitrobenzene in the Presence of 18-Crown-6

1993 ◽  
Vol 58 (6) ◽  
pp. 1324-1336 ◽  
Author(s):  
Petr Vaňura ◽  
Emanuel Makrlík
Keyword(s):  
Aqueous Solution ◽  
Stability Constants ◽  
Organic Phase ◽  
Perchloric Acid ◽  
Extraction Constants ◽  
Individual Extraction Constants

A study has been made of the extraction of Sr and Ba in an aqueous solution of perchloric acid-18-crown-6-bis-1,2-dicarbollylcobaltate-nitrobenzene. It was found that the organic phase contains complexes of the ML2+org type ( M = Sr2+, Ba2+) that are converted to ML22+org when the concentration of crown (cL) is greater than the concentration of bis-1,2-dicarbollylcobaltate (cB). The values of the corresponding extraction constants, individual extraction constants and stability constants of the extracted species in the organic phase were determined. The system can be utilized for separation applications at concentrations here cL < cB.

Contribution to the thermodynamics of complexes of alkali metal cations with dibenzo-18-crown-6 in water-nitrobenzene extraction system

1984 ◽  
Vol 49 (1) ◽  
pp. 39-44 ◽  
Author(s):  
Emanuel Makrlík ◽  
Jaroslava Hálová ◽  
Miroslav Kyrš
Keyword(s):  
Alkali Metal ◽  
Alkali Metal Cation ◽  
Alkali Metal Cations ◽  
Complex Species ◽  
Cation Order ◽  
Extraction Constants ◽  
Equilibrium Data ◽  
Individual Extraction Constants ◽  
The Stability ◽  
The Individual

The stability constants for the ML+ complex species, where M+ is an alkali metal cation and L is dibenzo-18-crown-6, in nitrobenzene saturated with water were calculated by employing published equilibrium data. The stability is found to increase in the cation order Li+ < Cs+ < Rb+ < K+ < Na+. For the NaL+, KL+, RbL+, and CsL+ complex cations the individual extraction constants in the water-nitrobenzene system were determined; their values increase in the series Na+ < K+ < Rb+ < Cs+.

The Extraction Transfer of H+-18-Crown-6 Species across the Water-Nitrobenzene Phase Boundary in the Extraction of Aqueous Solutions of Perchloric Acid by Nitrobenzene in the Presence of 18-Crown-6

1993 ◽  
Vol 58 (3) ◽  
pp. 483-495 ◽  
Author(s):  
Petr Vaňura ◽  
Iveta Juklíková
Keyword(s):  
Experimental Data ◽  
Phase Boundary ◽  
Perchloric Acid ◽  
Free Enthalpy ◽  
Nitrobenzene Phase ◽  
Extraction Constants ◽  
L Systems ◽  
Individual Extraction Constants ◽  
The Individual ◽  
The Given

A study was made of the extraction of perchloric acid in water-nitrobenzene-18-crown-6 (hereafter L) systems. The experimental data was interpreted on the basis of the assumption that the extraction occurs according the equations H+aq + ClO4,aq- ↔ H+org + ClO4,org- and H+aq + Laq + ClO4,aq- ↔ HL+org + ClO4,org-. Crown is also protonated in the aqueous phase according to the equation H+aq + Laq ↔ HL+aq. The values of the corresponding extraction constants, the protonation constants of 18-crown-6 in nitrobenzene and water and the individual extraction constants of the HL+ species in the water-nitrobenzene system were determined, along with the magnitude of the molar free enthalpy for the transfer of these species across the given phase boundary.

Extraction of hafnium by means of some substituted 1-phenyl-3-methyl-4-benzoyl-pyrazol-5-ones

1981 ◽  
Vol 46 (8) ◽  
pp. 1901-1905 ◽  
Author(s):  
Oldřich Navrátil ◽  
Jiří Smola
Keyword(s):  
Ionic Strength ◽  
Aqueous Phase ◽  
Dissociation Constants ◽  
Parent Substance ◽  
Benzoyl Group ◽  
Extraction Constants ◽  
Extraction Parameters ◽  
Substituted 1

Distribution between aqueous phase and benzene or chloroform was studied for 1-phenyl-3-methyl-4-benzoylpyrazol-5-ones with 2-chloro, 4-methoxy, 3-nitro, and 4-nitro substitution in the benzoyl group (ionic strength of the aqueous phase 0.1) and for hafnium in their presence (ionic strength 2.0). The distribution and dissociation constants of the reagents and the extraction constants of their hafnium complexes were determined. Hafnium was found to be extracted as the HfA4 species. The extraction parameters of the derivatives in question do not differ substantially from those of the parent substance.

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