Salt complexes of cyclic polyethers. Distribution equilibriums

Extraction of Several Divalent Metal Picrates by 18-Crown-6 Ether Derivatives into Benzene: A Refinement of Methods for Analyzing Extraction Equilibria

“…Therefore, extraction constants, K ex and K ex± , can be defined as follows (Frensdorff, 1971;Jawaid & Ingman, 1978;Takeda & Kato, 1979;Kikuchi & Sakamoto, 2000;.…”

“…Ion-pair complexes (MLA n ) with crown ethers, L, have dissociated into complex ions, ML n+ or MLA + , and pairing anions, A  , at n = 1 or 2 in organic and aqueous phases (Frensdorff, 1971;Jawaid & Ingman, 1978;Kolthoff & Chantooni, 1993;Takeda, 2002;Kikuchi & Sakamoto, 2000;Kudo, 2013). For example, KLPic dissociates into KL + and picrate ion (Pic  ) in dichloromethane (Frensdorff, 1971) and water (Takeda, 2002) at L = dibenzo-18-crown-6 ether (DB18C6) and n = 1 and in 1,2-dichloroethane (DCE) at L = 18-crown-6 ether, 18C6, and n = 1 (Kolthoff & Chantooni, 1993); CaLA 2 dissociates into CaLA + and A  at L = dicyclohexyl-18C6, A  = dipicrylaminate ion, and n = 2 (Jawaid & Ingman, 1978).…”

“…For example, KLPic dissociates into KL + and picrate ion (Pic  ) in dichloromethane (Frensdorff, 1971) and water (Takeda, 2002) at L = dibenzo-18-crown-6 ether (DB18C6) and n = 1 and in 1,2-dichloroethane (DCE) at L = 18-crown-6 ether, 18C6, and n = 1 (Kolthoff & Chantooni, 1993); CaLA 2 dissociates into CaLA + and A  at L = dicyclohexyl-18C6, A  = dipicrylaminate ion, and n = 2 (Jawaid & Ingman, 1978). In solvent extraction, the presence of such equilibria means at least the presence (Kudo, Harashima, Katsuta, & Takeda, 2011;Kudo, Katsuta, & Takeda, 2012;Kudo, Horiuchi, Katsuta, & Takeda, 2013) of the individual distribution of A  (or MLA + ) into the organic phase under the condition that the free A  (or MLA + ) is detected in the aqueous phase.…”

An Approximation Method for Determining Key Extraction Constants in the Equilibrium-Analysis of Cd(II) Extraction with 18-Crown-6 Ether into Some Diluents

“…Simplification of the convoluted procedures [3,4,10,12-17] for the M(II) extraction systems, compared with the procedures [1][2][3]5,6,8,9,11] for the monovalent-metal extraction ones, must stimulate an estimate of L functions by many workers. Unfortunately, there are still complicated treatments for the evaluation of equilibrium concentrations, such as…”

“…There are many studies for the metal extraction by crown compounds (L) and other extractants similar to L into various diluents, such as benzene, chloroform, 1,2-dichloroethane, and NB [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. In these studies, procedures of equilibrium analyses have become more difficult for primary users or outsiders of the field year by year.…”