Liquid anion exchanger

The liquid anion exchangers at present available are based largely on primary, secondary and tertiary aliphatic amines, e.g. the exchangers Amberlite LA.l [A/-dodecenyl(trialkylmethyl)amine] and Amberlite LA.2 [A/-lauryl(trialkyl-methyl)amine], both secondary amines. These anion exchange liquids are best employed as solutions (ca 2.5 to 12.5% v/v) in an inert organic solvent such as benzene, toluene, kerosene, petroleum ether, cyclohexane, octane, etc. 

Certain long-chain alkylammonium salts, notably tricaprylmethyl-ammonium chloride (Aliquat 336-S) and tri-Ao-octylamine hydrochloride (TIOA) are liquids, sometimes referred to as liquid anion exchangers, which can form extractable ion pairs or aggregates with anionic metal complexes in the... 

Rhodamine-B—H+ liquid anion exchangers e.g. Aliquat 336-S, TIOA... 

EDTA complexes of trivalent metals can be extracted successively with liquid anion exchangers such as Aliquat 336-S by careful pH control. Mixtures of lanthanides can be separated by exploiting differences in their EDTA complex formation constants. 

METAL EXTRACTION BY LIQUID ANION EXCHANGERS (TYPE lll-D)... 

All negatively charged metal complexes can be extracted by liquid anion exchangers, independent of the nature of the metal and the complexing ligand. Liquid anion exchange has extensive industrial application, and many examples are given in later chapters. Lists of extraction values are found in other works [e.g., 5, 21]. 

M Dolinsky, C Stein. Application of a liquid anion exchange resin to the separation of FD C colors from foods. J Assoc Off Anal Chem 45 767-769, 1962. 

CMPO, the selective extractant chemistry in TRU-Resin, can be impregnated into polymers that also contain organic fluor molecules to develop sensor materials, as described previously for crown ether and liquid anion-exchange chemistry. Actinide sensing by this approach has been described.96 135 137 Such sensor chemistries have potential for use in the development of on-line monitors. 

Horwitz, E. P., Dietz, M. L., Chiarizia, R., Diamond, H., Maxwell, S. L., and Nelson, M. R., Separation and preconcentration of actinides by extraction chromatography using a supported liquid anion exchanger Application to the characterization of high-level nuclear waste solutions, Anal. Chim. Acta, 310, 63-78, 1995. 

Bandyopadhyay and Das [151] extracted mercury from soils with the liquid anion exchanger Aliquat-336 prior to determination by cold vapour atomic absorption spectrometry. 

The method is suitable for the determination of Pb in gasoline in the range 1—lOOOpgml-1 (0.001—1 gl 1). The gasoline sample is diluted with MIBK and shaken with a solution of iodine in toluene. Iodo lead alkyl species are formed and these are stabilised with a liquid anion exchanger. Thus, the problem of the variable Pb response is overcome. This solution is compared with standards prepared in a similar fashion from Pb chloride in MIBK. 

EDTA, liquid anion exchangers oxine, tctraalkyiammonium salts acidic alkylphosphoric esters (liquid cation exchangers) e.g. HDBP, HDEHP... 

Sterri, S.H., Fonnum, F. (1978). Isolation of organic anions by extraction with liquid anion exchangers and its application to micromethods for acetylcholinesterase and 4-aminobutyrate aminotransferase. Fur. J. Biochem. 91 215-22. 

Zielinski RA, McKown DM. 1984. Determination of uranium concentration in water by liquid anion-exchange-delayed-neutron analysis. J Radioanal Nucl Chem 84 207-212. 

Graham, R. J. T., Bark, L. S., Tinsley, D. A. Quantitative thin-layer chromatography on liquid anion exchangers Part I. An investigation into some of the parameters involved in the direct densitometric determination of zinc. J. Chromatogr. 39, 211 (1969)... 

Alitame may be synthesized by a number of routes. For example, 3-(D-alaninamido)-2,2,4,4-tetramethylthietane is dissolved in water and L-aspartic acid N-thiocarboxyanhydride is then added in portions with vigorous stirring, maintaining the pH of 8.5-9.5. The pH is then adjusted to 5.5 and p-toluenesulfonic acid monohydrate is added over a period of one hour. The precipitated crystalline p-toluenesulfonate salt is collected by filtration. To obtain alitame from its salt, a mixture of Amberlite LA-1 (liquid anion exchange resin), dichloro-methane, deionized water, and the salt is stirred for one hour, resulting in two clear layers. The aqueous layer is treated with carbon, clarified by filtration, and cooled to crystallize alitame. 

Some amines which extract anions from aqueous solutions as ion pairs are called liquid anion exchangers [40,41]. They are marketed commercially under such trade names as Aliquat-336 and Amberlite LA-1. They are mixtures of secondary or tertiary amines, or quaternary ammonium salts, with alkyl groups having 7-12 carbon atoms. 

Thorium is one of the few multivalent metals [others are Au(III), Ce(IV), U(VI), and Cr(VI)] which are extractable as nitrate complexes from nitric acid solutions [25-28]. The extractants used include TBP in CCI4 [26,29], TOPO in cyclohexane, toluene or xylene [25,30,31], and triphenylarsine oxide in CHCI3 [27]. Other reagents used for extraction of the nitrate complex of thorium include dibutyl dithiophosphate in various organic solvents [32], dibutyl sulphoxide in xylene [28], and bis(2-butoxyethyl) ether [33].The liquid anion-exchanger Aliquat 336 in xylene [34] and a solution of tertiary ammonium salt (Hyamine) in dichloroethane [35] have been also proposed for extraction of Th. The presence of Li, Na, or A1 nitrate improves the extraction of thorium. Sulphate, phosphate, and tartrate do not interfere, but fluoride must be masked, e.g., by aluminium. Thorium has been separated from U and Pu with the use of Alamine 336 and TOPO (in xylene or cyclohexane) [36]. 

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