Extraction of some lanthanides by 12-crown-4 and 15-crown-5 from perchlorate media as ion pairs

Extraction of trivalent europium via emulsion liquid membrane containing PC-88A as mobile carrier

“…The viscosity, stability, and equilibrium constant of extraction are changed with the different diluents used, so that the selection of diluent can be also important. The following organic solvents have been used as common diluents for the extraction of rare earth elements: xylene (Nishiki and Bautista, 1983; Komasawa et al, 1990), n-heptane (Matsuyama et al, 1989a), toluene (Kondo et al, 1990a and1990b), n-dodecane (Denesi et al, 1982a and 1982b), kerosene (Teramoto et al, 1986), chloroform (Brown et al, 1983; Zhu and Izatt, 1990; Khalifa et al, 1988), etc.…”

Complexation of Americium(III) with Crown Ethers in Aqueous Phase

“…action of U(VI) with crown ethers has been reported [20]. The present studies suggest that attempts made by earlier workers [17,21,22] to correlate the extraction behaviour of trivalent lanthanide ions in analogous systems with their crystal ionic radii are not justified. There is no particular reason to invoke crystal ionic radii in order to explain the trends in distribution coefficients, even for other extraction systems involving actinide ions and crown ethers [23,24].…”