摘要:

Solvent extraction of phosphoric acid with Alamine 336 and tri-n-octylamine in toluene has been investigated. The activity of phosphoric acid is expressed as a polynomial of ionic strength and Bromley's model for electrolyte solutions is employed for calculation of ionic activity coefficients. Three species R3N (H3P04)nwith n = 1, 2 and 3 in the organic phase are taken into account for explanation of the distribution equilibria. The extraction constants have been determined as log K11= 2.05, log K12= 3.61 and log K13= 3.84 respectively. Aggregation and other non-ideal behaviour in the organic phase are described by letting the corresponding activity coefficient quotients be a function of the total concentration of acid in the organic phase.

ISSN:0736-6299    

DOI:10.1080/07366298608917899

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The extraction properties of dibenzo-1, 10-dithia-[18]crown-6 compounds have been investigated. Especially thiophilic metals are effectively extracted. The extraction of Ag(I), Pd(II) and Au(III) is much greater than that of Hg(II) or Cu(I). Alkali and alkaline earth metals are not extracted. The experimental results show the coordination of metal ions with sulfur is decisive for the extraction. The variation of the subetituents at the macrocyclic ring from CH3- t o CH2Cl-groups influences the extraction power considerably. In contrast, the substitution on the benzo groups shows a less strong effect. The influence of diluents and counter anions on extraction are comparable with results in known crown ether systems. Synergistic extraction is observed for silver and mixtures of dithiacrown compounds and HDEHP, n-caprylic acid or TBP.

ISSN:0736-6299    

DOI:10.1080/07366298608917900

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The fundamental characteristics and mechanism of extraction of cobalt (II) and nickel(II) by di-(1-methylheptyl) phosphinic acid (DMHPA) were studied. The extraction ability of cobalt(II), nickel (II) and various metals by DMHPA decreases in the order Fe(III) > Zn ≫ Pb(II) > Mn(II) > Cu(II) > Co(II) > Mg > Ca > Ni(II). The difference of the pH½values for nickel and cobalt reaches 2.06 pH units, which is apparently greater than those from extraction by di(2-ethylhexyl)phosphoric acid (DEHPA)and 2-ethyl-hexyl ester 2-ethylhexylphosphonic acid(DHEHPA).The slope analysis and IR spectroscopy reveal that the stoichiometrics of cobalt and nickel extracted species are Co(HA2)2and Ni(HA2)2(H2O)2respectively. As demonstrated by the study of the electronic spectroscopy the structure of the extracted complexes were shown as tetrahedral and octahedral configuration respectively. Furthermore, the coordination field parameters of the complexes were calculated.

ISSN:0736-6299    

DOI:10.1080/07366298608917901

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Cobalt(II) has been extracted by 50% (v/v) TBP solution in benzene from HC1, HBr, and LiC1 solutions containing water miscible alcohols and nonbesic and basic aprotic solvents. All solvents used caused the distribution ratio of Co(II) to increase due to diminished water activity and shifts in equilibria of cobalt(II) complexes in solutions. Hexamethylphosphor-triamide (HMPTA) has been found to behave exceptionally in that it extracted Co(II) from LiC1 solutions into neat benzene and in the presence of TBP induced a weak synergism caused by extraction of at least two mixed solvates.

ISSN:0736-6299    

DOI:10.1080/07366298608917902

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The species involved in the solvent extraction of zirconium(IV) from hydrochloric acid medium by mixtures of thenoyltrifluoroacetone (HTTA) and dipentyl sulphoxlde (DPSO) in benzene as the diluent seems to be Zr(OH)2(TTA)2(DPSO). Extraction of protactinium(V) by mixtures of HTTA and DPSO exhibits synergism but the extent of synergism is not very appreciable.

ISSN:0736-6299    

DOI:10.1080/07366298608917903

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The extraction of molybdenum(VI) from hydrochloric, nitric and sulphuric acid solutions by trioctyl-amine and tricaprylmethylannnonium chloride in benzene has been investigated under various conditions. The equiliblium expressions are proposed on the basis of the distribution data.

ISSN:0736-6299    

DOI:10.1080/07366298608917904

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The solvent extraction of Pr(III),Gd(III) and Yb(III) With 1-phenyl-3-methyl-4-benzoyl-pyrazol-5-one (HP) and Aliquat 336(QCl) in CCl4.C6H6and CHCl3, has been studied.The composition of the extracted species has been determined as LnP4−.Q+(Ln=Pr,Gd and Yb).The values of the equilibrium constants have been calculated. The extraction mechanism has been discussed.

ISSN:0736-6299    

DOI:10.1080/07366298608917905

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The activity coefficients of four extractants belonging to the carbamoylmethylphosphoryl class were measured by vapor-phase osmometry. All of the activity coefficients were within 15% of unity for concentrations up to 0.5Min toluene. As the basicity of the extractant's phosphoryl-group increases, its activity coefficient decreases. Octylphenyl-N,N-diisobutylcarbamoylmethyl-phosphine oxide [OφD(iB)CMPO] in toluene exhibited a marked decrease in activity coefficient upon equilibration with water or nitric acid. This helps explain a negative deviation from a third-power extractant dependency exhibited by americium distribution ratios, DAM, from 0.500 MHNO3. A positive deviation from a third-power extractant dependency, of DAMfor Am extracted from 5.00MHNO3, is explained by the alteration of the diluent's physico-chemical properties as its nitric acid content Increases. The extraction of nitric acid and water by toluene solutions of 0φD(iB)CMPO was also measured.

ISSN:0736-6299    

DOI:10.1080/07366298608917906

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The influence of organic solvent was studied in the anion-exchange extraction of metal-chloride complexes, typically, 2(Q·C1)O+ (M2+)W+ 2(Cl−)W⇌ (Q2·MCl4)O(Q+: liquid anion-exchanger; M2+: divalent metal ion; subscripts o and w denote organic and aqueous phases, respectively). When protic solvents such as chloroform, pentanol, octanol, andp-nonylphenol, were used as diluent, a large depression in the metal extraction was observed as compared with the extraction using aprotic solvents. The inhibitory effect decreased in the order, phenol > alcohol > chloroform, which was accounted for on the basis of protic solvation or hydrogen-bonding interaction to anionic species by these solvent molecules. Thus, strongly hydrophilic anion (chloride) is stabilized via “protic solvation”, whereas weakly hydrophilic or rather hydorphobic anion (metal-chloride complex) is not much susceptible to such protic solvation effect. This difference renders the extraction of the latter type anions uneffective in protic solvent. Additive effect in organic solution of variouso-substitutedp-tert-octylphenols further demonstrated this concept of “protic solvation effect”. Further, the extraction selectivity induced by such protic solvation was applied to liquid-membrane transport phenomena of anionic species. A new possibility in the separation among anions was discussed.

ISSN:0736-6299    

DOI:10.1080/07366298608917907

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Experimental studies were performed with a 4.0 in. (10.2 cm.) diameter extraction column containing ten dualflow type trays and operated in a controlled cycling mode. The systems methyl isobutyl ketone/acetic acid/water and toluene/acetone/water were used. The overall stage efficiency was found to be a function of the ratio of the volume of a phase transferred during a cycle to the volume of that phase held up on the tray, of the feed-to-solvent ratio, and of the phase throughput rates. A non-equilibrium model was developed to represent the experimental data. For the HIBK/acetic acid/water system, overall stage efficiencies were in the range of 30 to 38 percent, corresponding to HETS values of 0.46 to 0.55 meters. For the toluene/acetone/water system, overall stage efficiencies were in the range of 20 to 31 percent, corresponding to HETS values of 0.55 to 0.95 meters.

ISSN:0736-6299    

DOI:10.1080/07366298608917908

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor