Micelle formation as a factor influencing the mode(s) of metal ion partitioning into N-alkylpyridinium-based ionic liquids (ILs): implications for the design of IL-based extraction systems

2017 ◽  
Vol 19 (23) ◽  
pp. 5674-5682 ◽  
Author(s):  
James L. Wankowski ◽  
Michael J. Kaul ◽  
Mark L. Dietz

In the extraction of alkali and alkaline earth cations by a crown ether into certain N-alkylpyridinium-based ILs, the balance between neutral complex/ion-pair partitioning and ion exchange is significantly altered by the formation of micelles in the aqueous phase involving the IL cation.

1993 ◽  
Vol 2 (4) ◽  
pp. 295-299 ◽  
Author(s):  
Toshio Takahashi ◽  
Yoichi Habata ◽  
Tetsuyuki Okumachi

1992 ◽  
Vol 5 (10) ◽  
pp. 663-669 ◽  
Author(s):  
Roberta Cacciapaglia ◽  
Luigi Mandolini ◽  
David N. Reinhoudt ◽  
Willem Verboom

2015 ◽  
Vol 39 (8) ◽  
pp. 6099-6107 ◽  
Author(s):  
Igor Sviben ◽  
Nives Galić ◽  
Vladislav Tomišić ◽  
Leo Frkanec

The metal-ion extraction abilities of calix[4]arene derivatives1and2are largely dependent on the type of the amide group forming the cation-binding site. Tertiary-amide derivative2was shown to be an excellent extractant for most alkali and alkaline earth cations.


1984 ◽  
Vol 62 (3) ◽  
pp. 498-506 ◽  
Author(s):  
Lynn M. Dulyea ◽  
Thomas M. Fyles ◽  
Dennis M. Whitfield

The extraction and transport of alkaline earth cations from a basic to an acidic solution across an artificial membrane by crown ether carboxylic acids are reported. Monocarboxylate carriers achieve the transport via 2:1 complexes or by ternary complexes in the presence of readily extractible anions, while dicarboxylate carriers transport cations as 1: 1 complexes. Both types of carrier exhibit two regimes of kinetic behaviour depending on the relative concentrations of the carrier and the metal ion: a zero order regime in which the rate depends only on the carrier concentration, and a reversible consecutive first order regime in which the rate depends only on the metal ion concentration. In the former, the rate of adsorption of the carrier on the interface is presumed to be rate limiting while in the latter, the diffusion of metal ion to the interface is rate limiting. Carrier structure exerts a general influence over both the rate and selectivity of transport but this influence varies with the kinetic regime considered.


2017 ◽  
Vol 87 ◽  
pp. 51-58 ◽  
Author(s):  
Fatemeh Alipour Zaghmarzi ◽  
Mansour Zahedi ◽  
Adeleh Mola ◽  
Saboora Abedini ◽  
Sattar Arshadi ◽  
...  

1994 ◽  
Vol 72 (2) ◽  
pp. 437-447 ◽  
Author(s):  
Erwin Buncel ◽  
Anurag Kumar ◽  
Hai-Qi Xie ◽  
Robert Y. Moir ◽  
J. Garfield Purdon

The reactions of β-phenylmercaptoethyl p-nitrophenolate (1) with three potassium oximates, viz. potassium 2,3-butanedione monoximate (BDOK), acetophenone oximate (APOK), and acetone oximate (AOK) have been investigated in two nonhydroxylic dipolar aprotic solvents, tetraglyme and dimethyl sulfoxide (DMSO). The reaction products, as determined by 1H NMR spectroscopy, were p-nitrophenoxide ion and phenyl vinyl sulfide, in accord with an elimination process. A kinetic spectrophotometric study showed that in tetraglyme, the addition of oxime and water in small amounts drastically decreased the rate of reaction of 1 with APOK as a result of hydrogen-bonding interactions with the oximate anion. In tetraglyme as solvent the addition of 2.2.2 cryptand greatly enhanced the reactivity of the oximates but the macrocyclic crown ether DC-18-C6 had much smaller effect on rate. The results are consistent with formation of a crown ether-complexed potassium oximate ion pair, which is much less reactive than the free anion formed in the presence of 2.2.2 cryptand but more reactive than the potassium oximate ion pair. The kinetic data were analyzed to obtain specific rate coefficients for reaction of APOK as the dissociated anion, the ion-paired species, and as the crown ether-complexed oximate; equilibrium constants for potassium oximate ion pair formation and for the crown ether-complexed ion pair were obtained. In DMSO as solvent the rate of reaction remained unaffected on addition of the metal ion complexing agents, indicating that ion pairing is not important in this solvent. The reactivity of the free oximate anions in both solvents increased in the order BDOK < APOK < AOK, which parallels the pKa's of the corresponding oximes in DMSO. The unusually high reactivity of oximates in the low polarity tetraglyme compared to polar DMSO could be explained on the basis of stabilization of the transition state in tetraglyme. Trends in kTG/kDMSO for the oximates follow reactivity–selectivity considerations.


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