摘要:

An approach has been developed to describe the phase equilibrium in liquid two-phase three-component systems: polar organic solvent - water - salt ( Timmermans' systems ); polymer - water -salt; polymer (1) 7 water - polymer (2).

ISSN:0736-6299    

DOI:10.1080/07366299008918005

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The metal extractant Cyanex© 272 contains bis(2,4,4-trimethylpentyl)-phosphinic acid (BTMPPA) as the main component and trioctylphosphine oxide as an impurity. As-received Cyanex 272 and pure BTMPPA were observed to significantly differ in respect to both their phase behavior during saponification and to their copper extraction ability. The differences were elucidated by investigating the effects of an addition of small amounts of tri(n-octyl)phosphine oxide (TOPO) on the phase equilibria in the system Water(2.4M NaOH)/BTMPPA/n-Hexane at 25 °C as well as in the system Water(2.4M NaOH)/BTMPPA at various temperatures. In the absence of TOPO a large microemulsion region and a small region of lyotropic liquid crystalline phase with lamellar structure are formed. When TOPO is added into the system the lamellar phase gradually disappears. The effects of TOPO on metal extraction equilibria were studied by measuring the distribution of copper(II) between a perchloric acid solution and a BTMPPA in chloroform solution in the presence and absence of tri(n-octyl)phosphine oxide.

ISSN:0736-6299    

DOI:10.1080/07366299008918006

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

ISSN:0736-6299    

DOI:10.1080/07366299008918007

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Experimental results are presented and discussed that demonstrate the interfacial character of the rate-limiting step (RLS) in the liquid-liquid extraction of Ni(II) by n-hexane solutions of dinonylnaphthalenesulphonic acid (HDNNS) in a non-dispersing stirred reactor. The possibility of a RLS in the bulk aqueous phase was excluded based on the classical criterion of volume-independent transfer rates per unit volume, and a criterion involving dissolution fluxes of the extractant into the aqueous phase. The aqueous diffusion film was excluded as the site to the RLS on the basis of HDNNS partition results. The combination of extractant distribution and dynamic transfer results is shown able to unequivocally identify the site of the RLS for this reactive system.

ISSN:0736-6299    

DOI:10.1080/07366299008918008

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Different adsorption isotherms such as the Gibbs, Szyszkowski,Frumkln and Temkin and polynomial were found as fits well to experimental interfacial tension isotherms for 2-hydroxy-5-alkylbenzaldehyde oximes at octane/water and xylene/water interfaces. The values of surface excess computed according to them increase as the length of the alkyl chain length increases for xylene/water system. Different behaviour was found at octane/water interface.

ISSN:0736-6299    

DOI:10.1080/07366299008918009

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Activity/correction coefficients of hydroxyoxime extractants and triisooctylamine in extraction systems containing non-solvating diluents were computed from the interfacial tension isotherms. The deviations from the Gibbs isotherm were considered. in which concentration instead of activities were used. The interfacial tension isotherms were matched by the spline function and the polynomial Computed activity/correction coefficients can be used to model the equilibrium of copper and palladium (II) extraction.

ISSN:0736-6299    

DOI:10.1080/07366299008918010

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Addition of t-butylcyclohexano-15-crown-5 (tBC-15C5) induces a synergistic effect in the extraction of Mn2+ion with didodecylnaphthalenesulfonic acid (HDDNS). This synergism is the result of the inner-sphere complexation of the crown ether to the manganese(II) ion. The formation of this complex, first suggested by distribution studies, has been confirmed by FTIR experiments. The C-O-C stretching bands for the crown ether ligand shift to lower frequency when Mn2+ion is extracted into a CC14 solution of HDDNS and tBC15C5. A similar C-O-C Btretching band is observed for the crystalline complex [Mn(15C5 ) (Bu3CS03)2] (where 15C5 = 15-crown-5 and Bu = n-butyl).Formation of analogous complexes is not observed for Fe3+, co2+,N2+,cu2+, or zn2+under similar conditions.

ISSN:0736-6299    

DOI:10.1080/07366299008918011

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

A mixture, consisting of trioctylamine and 2-ethyl hexanoic acid dissolved in toluene, extracts metal salts as well as water from aqueous salt solutions. Water uptake measurements showed a linear increase with salt concentration. IR spectra revealed -OH vibrations of both “free” and “associated” hydroxyl, which differ from those of bulk water. Data treatment of water uptake in accordance with Hogfeldt's model indicated the formation of mixed reversed micelles consisting of metal-salt-loaded mixed extractant and free extractant molecules. Micellization was also confirmed by osmometric measurements.

ISSN:0736-6299    

DOI:10.1080/07366299008918012

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The extractant th-isobutyl phosphine sulfide (TIBPS ), Cyanex 471, in toluene has been investigated for the extraction of Au (III) from aqueous HCI solutions. Analysis of the equilibrium data shows that the extraction proceeds via a solvating type mechanism by the formation of the species AuCI3.FI and AuCl3.2R, for which formation constants are log 677 β= 34.84 and log β= 42.04 respectively (R =TIBPS).

ISSN:0736-6299    

DOI:10.1080/07366299008918013

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (OφD(iB)CMPO) and extracted praseodymium form large elongated polymers whose sizes and shapes were measured by small-angle neutron scattering (SANS). The particles were 17-40 Ȧ in diameter and up to 500 Ȧ long. The polymers are produced at low 0φD(iB)CMPO/Pr ratios, and their sizes decrease as OφD(iB)CMPO/Pr ratio increases. A model for the polymers that invokes bridging of successive praseodymium atoms by the two functional groups of 0φD(iB)CMP0 is supported by: (a) the formation of polymers by two other Afunctional extractants, whereas a comparable monofunctional extractant fails to form polymers, and (b) the long and thin shape of most of the observed polymers, exhibiting a radial extension that is consistent with the model. Four comparable carbamoyl-alkyl-phosphoryl extractants have been examined by SANS for their capacity to form polymers with praseodymium in C6D6. Consistent with the model, the extractants, having the more basic amidic carbonyl moiety form polymers; one with less a basic carbonyl group does not form a polymer,

ISSN:0736-6299    

DOI:10.1080/07366299008918014

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor