Extraction CMPO-calix arenes

Wide-rim tetra(CMPO) calix[4]arenes present good extraction abilities and also rather good selectivities at high acidity. But, the stability toward hydrolysis is not very good. N-methylated compounds exhibit low extraction efficiency, but higher stability toward hydrolysis when they are in contact with strong nitric acid (3 M). 

Tetra(CMPO) cavitands present nearly the same extraction properties as wide-rim tetra CMPO calix[4]arenes, but a slightly lower selectivity. 

Extraction by Wide-Rim CMPO Calix[4]arenes and Oligomers... 

The wide-rim CMPO calix[4]arenes are the most efficient compounds for the extraction of trivalent actinides and lanthanides. They are also the compounds that display the highest selectivity along the lanthanide series, provided that phosphorus atoms are linked to phenyl groups. They also display a higher selectivity than the calixarene-bearing diphosphine oxide, where the phosphorus atom is linked to phenyl units CPo21.176- ... 

Since in the case of p-H calixarenes, a precipitate occurred at the water/organic interphase, extraction tests were carried at a concentration of 10" M for these compounds. The presence of tert-butyl or benzyloxy at the wide rim helps to solubilize the complexes. The distribution ratios are compared to wide-rim CPw3 and narrow-rim CPn3 (Table 4.34).179 For all CMPO-calix[6,8]arenes, distribution ratios of the two cations studied (Eu and Am) increase with increasing HN03 concentration, in agreement with what is observed with tetramers bearing CMPO residues... 

Sansone, F., Fontanella, M., Casnati, A., Ungaro, R., Bohmer, V., Saadioui, M., Liger, K., Dozol, J.F. 2006. CMPO-substituted calix[6]- and calix[8]arene extractants for the separation of An3+/Ln3+ from radioactive waste. Tetrahedron 62(29) 6749-6753. 

In the second project, gathering nine teams from six EC countries, more than 150 new extractants were prepared and studied, and the target was reached for the decategorization of waste. Dialkoxy calix[4]arene-crown-6 for cesium, octaamide calix[8] arenes, and CMPO-like calixarenes for actinides display much higher complexing and extracting abilities than other classical extractants, crown ethers, or dicarbollides proposed and sometimes used for this purpose. 

Extraction by Wide-rim N-methylated CMPO Calixarenes Two calix[4]arene tetraethers (pentoxy CPwl7 and tetradecyloxy CPwl8) bearing four -N(Me)-C0-CH2-P(0)Ph2 residues on their wide-rim were synthesized for the first time.170 Their ability to extract lanthanides and actinides from an acidic aqueous... 

Bohmer et al. also synthesized calixarenes bearing one or more CMPO moieties and another functionality (malonamide or carboxylate). These calixarenes display lower extracting ability than CPw3, and contrary to expectations, these functions do not lead to a new order of selectivity. Calix[4]arenes bearing one or two adjacent malonic acid groups (NH-C(0)-CH2-C00H) adjacent to CMPO functions at the wide rim were unstable and decomposed during the complex-ation studies. 

Coupez, B., Wipff, G. (2004), The Synergistic Effect of Cobalt-dicarbollide Anions on the Extraction of M Lanthanide Cations by Calix[4]arene-CMPO ligands a Molecular Dynamics Study at the Water-"oil" Interface, C. R. Chimie Acad. Sc. Paris, in press. 

Maximum extraction occurs from 1 to 3 M HNO3 into o-nitrophenyl-hexyl-ester and the following separation factors were measured with respect to trivalent americium for 1 mM ligand concentration and 10-4 M metal ions Sf(Am/Ln or Cm) = 2.00 (La), 52 (Ce), 1.72 (Nd), 2.78 (Sm), 5.15 (Eu), 7.15 (Cm). Following this study numerous CMPO-substituted calix[4]arenes have been synthesized and tested. 

Also a 1 1 synergic mixture of two calix[4]arenes, the first substituted with four CD anions and the second with four CMPO functions, showed similarly high extraction efficiencies as the most potent VIb-e compounds. But due to low solubility of the components in low-polar solvents, the... 

GRAPH 19.3 Comparison of the extraction properties (dependence of log on logarithm of nitric acid concentration) of low-rim calix[4]arenes bearing two ions and two CMPO groups in opposite positions of the platform. The compounds differ in length of the alkyl spacer (for Via = CjlT, VIb = C3Hg, Vic = C Hg, VId = CjH,o, Vie = CgH,2, Vlf = CjH, ) between the platform and CMPO function. Extractants are at very low concentrations 1 x 10 M in HMK/TPH (1 1). (T, the log value were determined as higher than 2.)... 

Cycle Experiments of Eu + Extraction and Stripping Using the Calix[4]arene Via (Ethylene Spacer between Platform and the CMPO Functions)... 

Mikulasek, L., Grtiner, B., Dordea, C. et al. 2007. Tert-butyl-calix[4]arenes substituted at the narrow rim with cobalt bis(dicarbollide)(l-) and CMPO groups—new and efficient extractants for lanthanides and... 

---