Hydrophobic tartaric acid monoamides as complexing and tensioactive agents

A simple method for the preparation of monoamide derivatives of tartaric acid is proposed. The direct synthesis of the products HOOC-CHOH-CHOH-CONHR, where R is an alkyl chain with 3, 8, 10 or 14 carbons, from tartaric acid and the corresponding amines is described. The tensioactive properties of the C-8 molecule have been evaluated; this compound forms micelles in water and the critical micellar concentration has been measured. The complexing ability of these molecules toward the trivalent lanthanide cation Pr(III) has been checked with the C-3 compound. The formation of a neutral complex and the hydrophobic character of these molecules make them good candidates for liquid-liquid extraction in order to extract and separate lanthanide(III) ions.