摘要:

The kinetics of palladium extraction from chloride solutions by PAN has been studied in the presence ofQ+,C1−or Q+,SCN−Enhancement in the extraction rate by addition of quaternary ammonium salts to the organic phase was predicted from the phase-transfer of the metal complex to the bulk organic phase as an ion-pair. The expression for the rate determining step has been derived as:

ISSN:0736-6299    

DOI:10.1080/07366298708918606

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Extracting hydrophobic gels have been prepared by swelling cross-linked polybutadiene with solutions of 4-acylpyrazol-5-ones (HL) in toluene, chloroform and carbon tetrachloride. The extraction of copper from perchlorate medium has been studied. Distribution curves close to those obtained in the pure liquid-liquid extraction show that the polymer has no effect on the thermodynamics of the liquid-gel extraction. The diffusion of the copper chelates CuL2into the gels appears as a controlling rate factor of the extractions which depends on the polybutadiene cross-linkage.

ISSN:0736-6299    

DOI:10.1080/07366298708918607

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Distribution equilibria of lead(II) in the extraction with di(2-ethylhexyl)phosphoric acid and 2-ethylhexyl 2-ethylhexylphosphonic acid in toluene from aqueous ammonium nitrate solutions were measured at 303 K to elucidate the concentration dependencies of the reactant species on the distribution ratio. It was found that lead(II) is extracted as the mononuclear complex, PbR22HR, with the former extrac-tant while it is extracted not only as the complex, PbR22HR, but also as the complex, Pb(NO3)R;HR, accompanied by simultaneous transfer of nitrate anion with the latter ex-tractant. The extraction equilibrium constants of these complexes were evaluated as well as the stability constants of lead(II) -nitrato complexes, Pb(NO3)+, Pb(NO3)2and Pb(NO3)−3.

ISSN:0736-6299    

DOI:10.1080/07366298708918608

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

A study of the equilibrium extraction behavior of a series of representative tervalent lanthanide ions, La, Pr, Eu and Yb, was conducted using a CC1 solution containing either 2-( 3, 5-dibromo-2-pyridyxazo) -5-di-ethyl-aminophenol (DBPADAP or HL) alone or combined with TOPO. With HL,the lanthanides are extracted as simple chelates LnL„. In the presence of both HL and TOPO, the extracted species may be Ln(OH)L2(TOPO).. Solvent extraction equilibrium constants of the lan-thanide-DBPADAP complexes are reported. the extractant, DBPADAP, displays good selectivity for the lighter lanthanides.

ISSN:0736-6299    

DOI:10.1080/07366298708918609

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Cobalt (II) was extracted by thenoyltrifluoroacetone (HTTA) and its mixture with dibenzo-18-crown-6(Dbl8C6) at different temperatures in nitrobenzene (Nb); toluene (Tol) or their mixtures, from perchlorate aqueous media of constant ionic strength (o.l;H+,NaClO4) buffered with acetic acid-sodium acetate solutions. Slop analysis of the experimental results indicated that the stoichiometry of the chelate and the adduct extracted are Co(TTA)2and Co(TTA)2•Dbl8C6, under all the experimental conditions investigated. The extraction constants of the chelate (k2o)’ tne mixed species (k2land the formation constant of the adduct ( B2lwere evaluated for the different diluents used at the different temperatures. It was found that log k2oand log2lincrease by increasing the dielectric constant (€ ) of the diluent whereby log B2ldecreases by increasing €. These results were expressed in terms of linear free energy relationships. From the effect of the temperature on the different constants evaluated; the thermodynamic constants of the systems were calculated and discussed in terms of the nonspecific effect of the diluents used and the dehydration of the extracted chelate to form the adduct.

ISSN:0736-6299    

DOI:10.1080/07366298708918610

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The details of the synthesis and purification of symmetrical and unsymmetrlcal carbamoylmethylphosphine oxides (CMPO 's) are described. The approaches used to provide a variety of substitution patterns around the two potential donor groups include the Arbusov, Michaelis-Becker and Grignard reactions. Several methods for purifying the extractants were studied. The use of acidic and basic ion exchange resins in conjunction was developed for the removal of acidic impurities which are very troublesome to the extraction performance of these compounds.

ISSN:0736-6299    

DOI:10.1080/07366298708918611

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The details of the NMR spectra (31P,13C,1H), for selected carbamoylmethylphosphine oxides are provided. A correlation between the31P chemical shift and the nitric acid extraction constant (kHNO3) has been determined for these compounds. The carbon and proton spectral data are usually very complex but a number of generalities in this data are noted which aid in the structural assignments. The mass spectral data is presented and some indication of the probable fragmentation pattern Is given.

ISSN:0736-6299    

DOI:10.1080/07366298708918612

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The distribution data for the impurities (SO=4, F−, Fe, Al and Mg) during purification of wet phosphoric acid (WPA) with di-n-propy1 ether (DPE), di-n-propy1 ether containing 6. 5% of the isomer n-propylriso-propyl ether (DPE(M)) and di-iso-propyl ether (DIPE) at 25°C are reported. The distribution of phosphoric acid (PA)(SO=4, F−, Fe, Al and Mg between the conjugated phases has been investigated. The system W-WPA-DIPE shows a three-liquid-phases-at-equilibrium zone with 65.7% of phosphoric acid in the aqueous phase, 43.9% in the heavy organic phase and 4.3% in the light organic phase. The degree of purification increases, for the three solvents studied, when decreasing the PA concentration in the organic phase (except for F−when using DPE}. Purification data for iso-arayl alcohol (1) and these three solvents are compared, showing that di-n-propyl ether with 6.5% of the isomer propyl-iso-propyl ether is the best solvent (from all solvents investigated in these series) for the purification of the wet process phosphoric acid studied.

ISSN:0736-6299    

DOI:10.1080/07366298708918613

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Studies of sorption of lanthanide ions (Ln3+) by vermiculite in relation to pH of the equilibrium solution and the comparison of potentiometric titrations of lanthanide nitrate solutions a) containing vermiculite and b) without vermiculite suggested that Ln3+ions undergo hydrolysis in the interlayer space of the clay mineral. Studies of the ion-exchange equilibria of Ln3+with Mg2+revealed that vermiculite had a high affinity for Ln3+, especially at low Ln3+concentrations in the solid phase. X-ray diffraction analysis of mixed Ln-Mg-exchanged vermiculite suggested segregation into crystallites of Mg-vermiculite and Ln-vermiculite. The replacement of K+by Ln3+was more difficult than the replacement of Mg3+;.

ISSN:0736-6299    

DOI:10.1080/07366298708918614

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor