ISSN:0736-6299    

DOI:10.1080/07366299008918028

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Mono-acidic liquid ion exchangers (extractants) containing the phosphonyl functional group arc reviewed.

ISSN:0736-6299    

DOI:10.1080/07366299008918029

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The extraction of zinc was studied with solvents containing bis (2,4,4-trimethylpentyl)phosphinic acid and its monothio and dithio analogues. Comparative data are presented to illustrate the effect of composition (sulphur substitution) on the extraction and stripping characteristics of the three reagents. Special emphasis is given to the selective separation of zinc from sulphate solutions containing calcium. The effect of aralkyl versus alkyl groups in the molecule is also illustrated and important extractant properties such as hydrolytic stability and aqueous solubility are discussed.

ISSN:0736-6299    

DOI:10.1080/07366299008918030

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The equilibrium and kinetics of the extraction of copper with 3-alkylpentane-2, 4-dione (-H, -C2H5, -Ph, and -C8H17) were studied. It was found that the overall equilibrium constant is related to the proton disscoiation constant and that the ratio of the stability constants of the copper chelate, β2/β12was independent of the alkyl chain length of the β-diketone. The rate constants for the reactions between cupric ion and the β-diketones in the aqueous phase were obtained by the relaxation method. The values decreased in the order -H>-Ph>-C2H5. The observed extraction rates were explained by a kinetic model using the measured physicochemical properties.

ISSN:0736-6299    

DOI:10.1080/07366299008918031

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Equilibrium data are reported for the extraction of phenol at 288, 293 and 298 K with n-butyl acetate (NBA), acetophenone (AP) and mixtures of NBA + AP and methyl isobutyl ketone (MIK) + AP. A synergistic behaviour is observed for the system phenol-water-(NBA/AP). Several equations have been used to correlate the experimental data: van't Hoff, Redlich-Kister and other polynomial equations. Reported data were compared with those available in the literature.

ISSN:0736-6299    

DOI:10.1080/07366299008918032

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The thermodynamics of extraction of some lanthanide ions and bismuth, aluminium, calcium and zinc ions from perchloric acid into solutions of dinonylnaphthalenesulphonic acid have been studied. Extraction of the trivalent ions is dominated by the entropy of complexing. Electrostriction of large complex micelles by the complexed ion is postulated in order to account for the entropy effect. In the case of divalent ions, the enthalpy of dehydration of the ion is more important. A strategy for improving the separation factors is proposed.

ISSN:0736-6299    

DOI:10.1080/07366299008918033

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Adduct formation of 2-thenoyltrifluoroacetonato(tta) lantha-num(III), europium(III), and ytterbium(I II) with α-pheny 1 1 actic, α-methoxy phenyl acetic, salicylic, and o-methoxy benzoic acids in chloroform has been studied by solvent extraction technique. It has been found that 1anthanoid(111) chelates form more stable adducts with these carboxylic acids in the sequence: Yb(tta)3< Eu(tta)3< La(tta)3. The adduct formation constants as well as the separation factors obtained as the ratio of the constants between a pair of metals are the largest for α-phenyl lactic acid among these acids. The characteristics with α-phenyl 1actic acid would be caused by the action as bidentate unlike benzoic acid derivatives which work as monodentates owing to the internal complexa-tion through hydrogen bonding.

ISSN:0736-6299    

DOI:10.1080/07366299008918034

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The Bureau of Mines studied the extraction of copper (II) from acidic sulfate solutions using commercial extractants LIX 84, P5100, and PT5050. Mathematical models, consisting of sets of nonlinear mass action and mass balance equations, were solved using a commercial equation-solving program on a personal computer. The models suggest that LIX 84 is a mixture of monomelic and dimeric extractant with an extraction equilibrium constant of 145 and a dimerization constant of 65 L/mol; PT5050 appears to be a monomeric extractant with an extraction equilibrium constant of 53; and P5100 shows more complex characteristics, with a monomeric extraction equilibrium constant of 400, a dimer formation constant of 3.7 L/mol, and a modifier-complex formation constant of 5.8 L/mol. For all models, the relative error of fit was less than 6%.

ISSN:0736-6299    

DOI:10.1080/07366299008918035

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The distribution of lanthanides and yttrium between o-xylene solutions of Adogen-464Cl and aqueous solutions of LiCl was investigated over a broad range of LiCl and extractant concentrations. It has been found that stability constants of inner sphere lantha-nide chloro complexes decrease across the series, whereas the equilibrium constants for the transfer of the negatively charged chloro complexes increase with increasing lanthanide atomic number.

ISSN:0736-6299    

DOI:10.1080/07366299008918036

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The diffusion coefficient of HEHEHP in heptane has been measured by the modified Stokes cell technique at temperatures between 25 and 55°C. The Stokes cell was calibrated by measuring acetic acid diffusion with the pH-stat technique. The average diffusion coefficient of HEHEHP in heptane was determined to be 0.97 × 10−9m2/s at 25°C for HEHEHP concentrations of 0 - 0.1 kmol/m3. The diffusion coefficient did not vary significantly with HEHEHP concentration. The Wilke-Chane relationship was used to predict D values of 1.53 × lO−9m2/s and 1.01 × 10−9m2/s for the monomelic and dimeric species respectively. Comparison of the measured and predicted diffusion coefficients led to the conclusion that the HEHEHP was substantially dimenzed over the concentration range studied

ISSN:0736-6299    

DOI:10.1080/07366299008918037

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor