Crown calix .vertline.4.vertline. arenes, their preparation proc

Details Crown calix .vertline.4.vertline. arenes, their preparation proc Crown calix .vertline.4.vertline. arenes, their preparation proc

1995-10-04

1999-07-20

Mai, Ngoclan

Chemistry of inorganic compounds

Treating mixture to obtain metal containing compound

Radioactive metal

423 9, 210681, 210682, 210638, 210643, 546255, 549354, B01D 1100

Patent

active

059266872

DESCRIPTION:

BRIEF SUMMARY
The present invention relates to crown calix.vertline.4.vertline.arenes, their preparation process and their use for the selective extraction of cesium and actinides.
More specifically, it relates to crown calix.vertline.4.vertline.arenes able to selectively extract the cesium and actinides present in trace state in acid solutions which may or may not have high cation concentrations, such as the aqueous effluents coming from irradiated nuclear fuel reprocessing installations or irradiated fuel dissolving solutions.
In these effluents cesium 137 is one of the most noxious fission products as a result of its long half life (30 years). It is therefore of interest to selective eliminate it from the liquid effluents coming from the reprocessing plants, particularly concentrates of evaporators and acid solutions which may or may not have a high salinity more particularly due to the presence of sodium nitrate.
In view of the very similar chemical properties of sodium and cesium, it is extremely difficult to selectively extract the cesium present in these effluents, with a concentration generally below 10.sup.-6 mole/l, whereas the sodium concentration is approximately 4 mole/l.
In order to solve this problem, consideration has been given to the extraction of the cesium by means of macrocyclic ligands such as the para tert-butyl-calixarenes described in U.S. Pat. No. 4,477,377. The para tert-butyl-calixarenes used are the tetramer, hexamer and octamer and the best results are obtained with the hexamer and octamer, the tetramer not having a very good selectivity for separating the cesium from the potassium. This cesium extraction procedure is of interest, but suffers from the main disadvantage of only being applicable to the treatment of basic aqueous solutions, whereas most of the effluents resulting from reprocessing are acid solutions.
Other macrocyclic ligands such as crown ethers are also used for this purpose, as described in "Selective Extraction of Cesium from Acidic Nitrate Solutions with Didodecylnaphthalene sulphonic acid synergized with biz(tert-butylbenzo)-21 crown 7" by W. J. McDowell et al, Anal. Chem., 1992, 64, pp 3013-3017, but they have a low selectivity with respect to cesium.
The present invention specifically relates to novel calixarenes making it possible to selectively extract cesium from acid solutions and separate it from sodium with a good efficiency.
According to the invention, the calixarenes are crown calix.vertline.4.vertline.arenes of formula: ##STR2## in which R.sub.1 represents a group of formula X(CH.sub.2 CH.sub.2 X).sub.m or of formula X(CH.sub.2 CH.sub.2 X).sub.n YX(CH.sub.2 CH.sub.2 X).sub.n in which X represents O and/or N(R.sub.4) with R.sub.4 being a hydrogen atom or an alkyl group, Y representing a cycloalkylene or arylene group optionally having a heteroatom, m being equal to 3, 4, 5 or 6 and n equal to 1, 2 or 3, ##STR3## with p being equal to 5, 6, 7, or 8, --CH.sub.2 --CH.sub.2 OH or --CH.sub.2 COR.sub.5 with R.sub.5 representing a group of formula OR.sub.6, NR.sub.6 R.sub.7 or R.sub.6 in which R.sub.6 and R.sub.7, which can be the same or different, represent a hydrogen atom, an alkyl group or an aryl group, the two R.sub.2 possibly being different, and
In the above formula, the alkyl groups used for R.sub.2, R.sub.4, R.sub.6 and R.sub.6 can be straight or branched and are not necessarily identical, particularly for R.sub.2.
In general, the alkyl groups used for R.sub.4, R.sub.6 and R.sub.7 are alkyl groups having 1 to 4 carbon atoms. However, the alkyl groups used for R.sub.2 can also have carbon atoms, e.g. 1 to 12 and preferably 1 to 8 carbon atoms.
The aryl groups used for R.sub.6 and R.sub.7 generally have 6 to 14 carbon atoms. As examples of such groups, reference can be made to phenyl and naphthyl groups.
In the formula given hereinbefore, the term "cycloalkylene" group is understood to mean a divalent group derived from a cyclic hydrocarbon by removing a hydrogen atom at each of two carbon atoms of the cycle. As an example of such a group, reference can be mad

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Journal of the American Chemical Society, vol. 12, 1990, Gaston, PA US, pp. 6979 -6985, E. Ghidini et al. Complexation of Alkali Metal Cations by Conformationally Rigid, Stereoisomeric Calix(4) Arene Crown Ethers. Selective Electrodes Which Show Remarkably High 10.sup.5.0 -10.sup.5.3 Sodium/Potassium Selectivity, Chemistry Letters, 1994 pp. 1115-1118.

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