Atlas of metal—ligand equilibria in aqueous solution

Kragten, J.

doi:10.1016/0013-4686(79)87059-0

Cited by 124 publications

(93 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The stability constant of the mono-complex for rare earths(III) and TTA has not been reported, while a study with acetylacetone has been made. 17 The reported b 1 values for yttrium(III), europium(III), gadolinium(III) and ytterbium(III) are 10 5.90 , 10 5.87 , 10 5.90 and 10 6.18 , respectively, being 10 -30 times higher than those for TTA. Since such differences have been reported in many other metal systems 2,15 , the values in Table 1 are not unusual.…”

Section: Extraction Of Rare Earths(iii) With Tta Into Carbon Tetrachlmentioning

confidence: 95%

Stability Constants of Tervalent Rare Earth Metal Complexes with 1,10-Diaza-4,7,13,16-tetraoxacyclooctadecane in Aqueous Sodium Chloride Solutions

Masuda

1998

ANAL. SCI.

View full text Add to dashboard Cite

Because of their similarity in physical/chemical properties, the separation of adjacent tervalent lanthanoid metals from their mixture still remains problem. Several techniques have been described to achieve the separation, of which the liquid-liquid extraction method is probably one of the easiest and the most suitable. [1][2][3] Therefore, the separation of the lanthanoids by this method has been examined extensively.2,4,5 Although many extractants have been developed, the satisfactory separation by a conventional single-stage liquid-liquid extraction has not been achieved because of poor discrimination in extraction constants. Many combinations of extractants and adduct-forming reagents have been examined to improve the extraction selectivity. However, such reagents often operate in a reverse direction to reduce the overall extraction selectivity, and have not been successful in enlarging the separation factor.The use of a secondary ligand which forms a watersoluble complex species with these metals has the potential to improve the separation factor in the liquidliquid separation system. Previously, Tsurubou et al. demonstrated that the separation of some lighter lanthanoid complexes with bis(2-ethylhexyl)phosphoric acid in water-cyclohexane system was improved by the addition of 18-crown-6 into the aqueous phase. 6 The metal stability constant of 18-membered crown ethers such as 18-crown-6 or dibenzo-18-crown-6 increases as the atomic number of lanthanoids decreases, although the magnitude of such changes is rather limited. 5-12Crown ether-like macrocyclic ligands having aza groups instead of oxa groups are interesting as an extension of such secondary ligands. The factors affecting the stability of their metal complexes should be similar to those of the crown ethers, i.e., the fit between the ionic radius and the ring size. It is also noteworthy that the effective concentration of the secondary ligands can be regulated by controlling the pH of aqueous solutions by forming proton-adducts.In the present study, the stability of several tervalent rare earth complexes with 1,10-diaza-4,7,13,16-tetraoxacyclooctadecane (kryptofix 22), an aza-analogue of 18-crown-6, was investigated in aqueous 0.1 M sodium chloride solutions by a liquid-liquid extraction method. Experimental ReagentsAll the reagents were of analytical grade and were used without purification. The tervalent rare earth chlorides were supplied by Mitsuwa Chemicals, Osaka, Japan (praseodymium(III), europium(III) and ytterbium(III)) and by Nakarai Tesque, Kyoto, Japan (yttrium(III), gadolinium(III) and holmium(III)). The macrocyclic ligand kryptofix 22 (K22) was supplied by Merck, Germany. The 1-(2-thienyl)-4,4,4-trifluoro-1,3-butanedione (2-thenoyltrifluoroacetone; TTA) was obtained from Dojin Chemicals, Kumamoto, Japan. A colorimetric reagent, Arsenazo III, was obtained from Aldrich Chemicals, USA. The metal complex stability between tervalent rare earth metal ions (ytterium, praseodymium, europium, gadolinium, holmium and ytterbium) and 1,10-diaza-4,...

show abstract

Section: Extraction Of Rare Earths(iii) With Tta Into Carbon Tetrachlmentioning

confidence: 95%

Stability Constants of Tervalent Rare Earth Metal Complexes with 1,10-Diaza-4,7,13,16-tetraoxacyclooctadecane in Aqueous Sodium Chloride Solutions

Masuda

1998

ANAL. SCI.

View full text Add to dashboard Cite

show abstract

“…This tendency was consistent with the order of the formation constants for F to Al-APC complexes, i.e., log KAl-APC-F were reported as 5.41, 5.53, 4.95, and 3.14 for NTA, HEDTA, EDTA, and CyDTA, respectively. 35 The peak intensity at m/z 234 showed a linear dependence on the F -concentration from 0 to 50 μmol dm -3 without interference from 50 μmol dm -3 of Fe 3+ , the Fe species also having a relatively high stability constant with F -(log β1 = 5.30 34 ). This value is one or two orders of magnitude lower than those of the fluoride ionselective electrode (ISE) (LOD, about 1 μmol dm -3 ), 37 IC (LOD about 1 ppb 38 ), and AlF molecular absorption spectrometry (absolute LOD, 20 pg).…”

Section: Quantification Of Halides and Cyanide Ionsmentioning

confidence: 98%

“…Halides are well known as Lewis bases, which bind strongly with several metals in the aqueous solution. In the case of fluoride ion, it binds strongly with Al 3+ (first stability constant, log β1 = 6.30 34 ), therefore, NTA (500 μmol dm ). On ESI-MS a prominent peak for the [AlF(nta)] -ternary complex (m/z 234) was observed in the mass specrtrum.…”

Section: Quantification Of Halides and Cyanide Ionsmentioning

confidence: 99%

Electrospray Ionization Mass Spectrometry for the Quantification of Inorganic Cations and Anions

Hotta

Tsunoda

2015

ANAL. SCI.

View full text Add to dashboard Cite

“…(7) was done to estimate the extractable species, that is, the distribution ratios of Al(III), Ga(III) and In(III) were plotted against pH (or [HR]org at the fixed [HR]org) (or pH), where the a values were calculated based on the stability constant data taken from the literature. 19 The typical results are shown in Fig. 3.…”

Section: Kex -[Mrn]org[h+]n/[m3+][hr]org• (2)mentioning

confidence: 99%

Extractive Separation of Aluminum(III), Gallium(III) and Indium(III) Using Bis(1,1,3,3-tetramethylbutyl)phosphinic Acid and Its Sulfur Analogues

et al. 1996

View full text Add to dashboard Cite

The extraction behavior of A1(III), Ga(III) and In(III) was investigated using bis(1,1,3,3-tetramethylbutyl)phosphinic acid (MBP) and its sulfur analogues, bis(1,1,3,3-tetramethylbutyl)monothiophosphinic acid (MTP) and bis(1,1,3,3-tetramethylbutyl)dithiophosphinic acid (DTP) as extractants. A typical chelate extraction behavior was observed in these extraction systems in the pH range examined. The degree of extraction was in the order of In(III)>Ga(III)>Al(III). Moreover, the ability of extractants for mutual separation of these metals from one another decreased in the following order: DTP>MTP>MBP.The quantitative mutual separation of these metals can be achieved using DTP/hexane with single extraction. In the higher HCl concentration range, however, slight extraction of Ga(III) and In(III) was observed; this is due to the extraction of GaCla-and InCla-pairing with the protonated extractants.

show abstract

Atlas of metal—ligand equilibria in aqueous solution

Abstract: Fakten sind klar geschildert, noch Unverstandenes wird haufig deutlich so bezeichnet. Das Hauptanliegen des Buchleins.

Cited by 124 publications

References 0 publications

Stability Constants of Tervalent Rare Earth Metal Complexes with 1,10-Diaza-4,7,13,16-tetraoxacyclooctadecane in Aqueous Sodium Chloride Solutions

Stability Constants of Tervalent Rare Earth Metal Complexes with 1,10-Diaza-4,7,13,16-tetraoxacyclooctadecane in Aqueous Sodium Chloride Solutions

Electrospray Ionization Mass Spectrometry for the Quantification of Inorganic Cations and Anions

Extractive Separation of Aluminum(III), Gallium(III) and Indium(III) Using Bis(1,1,3,3-tetramethylbutyl)phosphinic Acid and Its Sulfur Analogues

Contact Info

Product

Resources

About