LAUSR

The exchange extraction constants corresponding to the general equilibria M+(aq) + NaL+(org) ⇌ ML+(org) + Na+(aq) and the respective M+(aq) + CsL+(org) ⇌ ML+(org) + Cs+(aq), taking place in the two-phase water–nitrobenzene and water–phenyltrifluoromethyl sulfone (abbrev. FS 13) systems (M+ = Li+, H3O+, Ag+, K+, NH4+\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{NH}}_{4}^{ + }$$\end{document}, Tl+, Rb+; L = calix[4]arene-bis(t-octylbenzo-18-crown-6), 1,3-alternate-25,27-bis(1-octyloxy)calix[4]arene-crown-6 and 1,3-alternate-25,27-bis(3,7-dimethyloctyl-1-oxy)calix[4]arene-benzocrown-6; aq = aqueous phase, org = organic phase) were evaluated. Stability constants of NaL+ and CsL+ were determined from the extraction of picrates and iodides by the solutions of L. Further, the stability constants of the ML+ complexes in nitrobenzene and FS 13 saturated with water were calculated. Enormously high selectivities were found in the systems under study.