LIPOPHILIC POLYTHIAMACROCYCLES AS PALLADIUM EXTRACTING AGENTS

Six new lipophilic thiacrown ethers (1-6), abbreviated as 2-octyl-9S3, 2-octyl-10S3, 2-octyl-12S4, 6-octyl-14S4, 3-octyl-16S4 and dioctyl-18 S6, were synthesized starting from different dithiols and dihalides. C s2CO3 is used for the cyclizations. The extraction behavior of palladi um (II) from nitric acid media with these reagents in chloroform has b een studied in terms of extraction equilibrium constants K-ex. The inf luence of parameters such as lipophilicity brought by alkyl chains, ma crocyclic cavity size and number of sulfur donor atoms on the extracti on behavior was investigated.