SOLVENT-EXTRACTION OF AMINO-ACIDS WITH CROWN-ETHERS AND CRYPTAND-222

The possibility of crown ethers: 18-crown-6 (18C6), benzo -18-crown-6 (B18C6), dibenzo-18-crown-6 (DB18C6) and cryptand 222 (222) to form co mplexes with the cationic species of a series of alpha - amino acids i n the protonated form (L - leucine, L - isoleucine, L - phenylalanine, L - methionine, L - valine and L - alpha-alanine) has been investigat ed. These cationic complexes can be extracted in chloroform, as ion pa ir complexes using pirate anion as counterion. The extraction constant s have been determined by UV Vis absorption method and they are in the 4.2 - 5.28, 4.19 - 4.54, 3.5 - 4.25, and 4.15 - 4.49 ranges when 18C6 , B18C6, DB18C6 crown ethers, and 222 cryptand, respectively are used.