Studies of Collectors. XIII. The Selective Flotation of Cesium Ion with Resorcinol-Type Calix[4]arenes with Alkyl Side Chains

The resorcinol-type calix[4]arenes with alkyl side chains, [4]Ar-Rn, were prepared and then investigated as flotation collectors of Cs+. Alkali metal ions (Na+, K+, Rb+, and Cs+) were extracted in the pH range of 9.5—12.5 with [4]Ar-Rn. Moreover, the surface-active [4]Ar-Rn had competence to float Cs+ as a complex in a foam film (adsorbates) when short-chain [4]Ar-Rn (n = 4—8) were used for foam fractionation, and as scum when long-chain [4]Ar-Rn (n = 8—16) were used for ion flotation. The Cs+ was floated selectively with [4]Ar-Rn from a mixture of Na+, K+, Rb+, and Cs+, due to the strong binding to Cs+.