Acid dissociation and two-phase distribution constants of eight β-diketones in several solvent extraction systems

Sekine, Tatsuya; Hasegawa, Yūko; Ihara, Naohiko

doi:10.1016/0022-1902(73)80104-6

Cited by 91 publications

(17 citation statements)

References 2 publications

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“…Thus, the solubility enhancement due to BTMP addition for several cobalt(III) chelates was investigated. benzoylacetone, and acetylacetone [39], respectively, and 9.66 for 8-quinolinol [40]. Figure 5 shows the dependence of the logarithmic values of the association constants ( 1 ) for the CoL 3 complexes and BTMP on the basicity (pK a ) of the CoL 3 ligands.…”

Section: Resultsmentioning

confidence: 98%

Analysis of the association of cobalt(III) chelates with fluorine-containing phenols in supercritical carbon dioxide

Ohashi

Shiratori

Kim

2016

Talanta

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Section: Resultsmentioning

confidence: 98%

Analysis of the association of cobalt(III) chelates with fluorine-containing phenols in supercritical carbon dioxide

Ohashi

Shiratori

Kim

2016

Talanta

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“…The distribution constant of the enol form is KdHE in Eq. (5) and that of the keto form is KdHK in Eq. (6) and each in the both phases is in the distribution equilibrium when the two phases are agitated continuously.…”

Section: Dhtta = ([He]org + [Hk]org)/([he] + [Hk])mentioning

confidence: 99%

Rate and Equilibrium of the Distribution of 2-Thenoyltrifluoroacetone in Carbon Tetrachloride-Aqueous Perchlorate Solution Systems

1996

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The rate and equilibrium of the liquid-liquid distribution of 2-thenoyltrifluoroacetone (Htta) was studied in carbon tetrachloride-aqueous 0.1 mol dm-3 sodium perchlorate solution systems at 298 K. The distribution equilibrium of Htta reached after two-phase agitation for 90 min and the distribution constant of the total Htta was 2.2X10; however, that of the enol form of Htta was higher than 2X102 and that of the keto form of Htta was 5.8X10'. By a spectrophotometric method and by a liquid-liquid partition method, the rate constant of the enolization and ketonization in the organic phase was measured. The former was 102 times higher than that of the latter; both were several orders lower than those in the aqueous phase. From these results, it was assumed that when Htta was initially added to the organic phase the main route of the two-phase distribution reaction was a transference of the enol form from the organic to the aqueous phase and its change to the keto form. In contrast to the change in the distribution ratio of Htta during two-phase agitation, the solvent extraction of metal ions from the aqueous phase with Htta did not change very much after a transient equilibrium was reached within a short time. This was examined with the extraction of indium(III). KeywordsKeto-enol tautomerism, 2-thenoyltrifluoroacetone, solvent extraction, kineticsBoth the keto and enol forms are present in a solution of a f3-diketone, and the molar ratio of these species is dependent on the nature of the medium. Several experimental methods were employed in order to determine the molar ratio of the keto and enol forms of the /3-diketones at equilibrium, such as titration methods/ as well as UV2 and NMR spectrometry.3 From these previous studies, it is known that in a waterimmiscible nonpolar organic solvent the enol form is predominant, while in an aqueous solution the keto hydrate form is predominant.This distribution process of a f3-diketone should affect the distribution ratio of $-diketone as well as the solvent extraction of certain metal ions with the /3-diketone when complex formation of the metal ions with the f3-diketone is not slow. Thus, when a f3-diketone transfers from an organic solution to an aqueous solution by agitation of the two solutions, the chemical form should be changed; since this does not proceed very rapidly, the distribution ratio of the /3-diketone as well as the solvent extraction of copper(II) with the extractant changed during the twophase agitation.4In the present paper, the effect of such a tautomeric transformation on the distribution ratio of 2-thenoyltrifluoroacetone (Htta) in carbon tetrachloride-aqueous perchlorate solution systems was studied by spectrophotometry and by measuring the change in the distribution ratio as a function of the two-phase agitation time. The effect of a tautomeric transformation of the extractant on the solvent extraction of metal ions in these systems was examined with indium(III) as an example. Experimental ReagentsAll of the reagents were of an analytical grade. ...

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“…The values of K d and K a of Htta have previously been determined as 10 1.85 and 10 -6.33 , respectively [23].…”

Section: Extraction Of Lanthanides(iii) With Htta In the Absence Of Pmentioning

confidence: 99%

Synergistic Extraction of Lanthanides(III) with 2-Thenoyltrifluoroacetone and Pyridine as Ion-Pairs and Adducts

Hirose

Inoue

Hasegawa

2010

SERDJ

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The extraction of lanthanides(III) (Ln(III)) from a 0.1 M sodium perchlorate solution with 2-thenoyltrifluoroacetone (Htta, HA) with pyridine (Py) into chloroform was investigated in a thermostatted room at 298 K, in order to examine in detail the variation of the reactivity of Ln(tta) 3 with an N-donor ligand across the lanthanide series. It was found that i) The extracted species was the ion-pair

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Acid dissociation and two-phase distribution constants of eight β-diketones in several solvent extraction systems

Cited by 91 publications

References 2 publications

Analysis of the association of cobalt(III) chelates with fluorine-containing phenols in supercritical carbon dioxide

Analysis of the association of cobalt(III) chelates with fluorine-containing phenols in supercritical carbon dioxide

Rate and Equilibrium of the Distribution of 2-Thenoyltrifluoroacetone in Carbon Tetrachloride-Aqueous Perchlorate Solution Systems

Synergistic Extraction of Lanthanides(III) with 2-Thenoyltrifluoroacetone and Pyridine as Ion-Pairs and Adducts

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