Extraction of sodium, potassium, and cesium by CHCl3 solutions of substituted polyethyleneglycols (PEG) in the presence of methanyl yellow anion is studied radiometrically using Na-22 and Cs-137 and photometrically. Extraction constants of the metals are determined for diphenyl, dinaphthyl, di-o-nitrophenyl, dialkyl, and diphosphineoxide ethers; di-, tetra-, penta-, hexa-, and octaethyleneglycols; mixed PEG-300, technical hydroxyethylaclohols, and alkylphenols. It is demonstrated that replacing terminal hydroxy groups by ethers reduces the extraction ability (EA) of the PEG. As the hydroxyethyl chain length increases, the EA increases and the influence of the terminal groups decreases. The EA increases especially sharply on going from derivatives of the tetra- to those of the pentaethyleneglycol. Regardless of the hydroxyethyl chain length and the type of substituent, log K(ex) decreases in the order K+ greater-than-or-equal-to Cs+ > Na+. The substituted PEG are similar in EA to dibenzo-24-crown-8 but are less selective.
