Solvent Extraction of Cadmium Picrate by 18-Crown-6 Ether into Several Less-polar Diluents and Nitrobenzene: Re-evaluation of the Corresponding Overall Extraction Systems

Application of Molar Volumes Obtained From a Solvent Extraction Method for Estimation of Sizes of Metal Complexes With Crown Ethers in Phases

“…In course of such studies, Takeda and coworkers have analyzed their extraction systems by applying the regular solution theory (RST) for the systems and then determined the solubility parameters and molar volumes (V j /cm 3 mol −1 ) of L (= j) and its ion pair complexes, ML + Pic − (Takeda, 2002). On the other hand, our groups have systematically studied the Cd(II) and Pb(II) extraction with 18C6 Kudo & Tomokata, 2018;Kudo et al, 2014;Kudo et al, 2015;Kudo et al, 2013a;Kudo et al, 2013b) or B18C6 (Kudo et al, 2017a) into various diluents and applied the same RST analyses for their systems Kudo & Tomokata, 2018;Kudo et al, 2014;Kudo et al, 2015;Kudo et al, 2013a). Here the analyses are based on the plots of log K ex,ip vs. log K D,L ; the symbols K ex,ip and K D,L denote an ion-pair extraction constant of complex ions, ML 2+ , with A − into an organic (org) phase and a distribution constant of the free L into the org one, respectively.…”