CATION COMPLEXATION BY CHEMICALLY-MODIFIED CALIXARENES .7. TRANSPORT OF ALKALI CATIONS BY P-TERT-BUTYLCALIX[N]ARENE ESTERS AND AMIDES

The co-transport of alkali thiocyanates, at 20 degrees C from an aqueo us source solution into an aqueous receiving solution through a bulk l iquid dichloromethane solution, is facilitated by p-tert-butylcalix-[n ]arene esters of lower rim calixarene acetic acids, named ethyl esters (n = 4, 5, 6, 8), by p-dealkylated calix[6]arene ethyl ester and the diethyl and pyrrolidine amides of a p-tert-butylcalix[4]arene. The tra nsport rates show that all derivatives, except the octamer, are effici ent and selective neutral ionophores for alkaline cations. The amides are better carriers than the esters and the pyrrolidinyl amide is more efficient for Li+, Na+ and K+ than the diethyl amide. Among the ester s, the most efficient, by far. is the pentamer, The tetra- and penta-e sters are selective for Na+, the hexaester for Cs+ and the tetraamides for K+. The Cs+/Na+ selectivity of the hexaester is increased by deal kylation in the para position. The same is shown to be displayed in ex traction. The data are compared with existing stability constant value s in methanol and extraction equilibrium constants or alkali, picrates , from water to dichloromethane. New extraction data are provided for alkali thiocyanates.