Synthesis, characterization and surface properties of 1-N-L-tryptophan-glycerol-ether surfactants

Abstract

A novel homologous series of 1-N-L-tryptophan-glycerol-ether surfactants was synthesized and characterized. The precursor compounds, 3-alkyloxy-1-chloropropan-2-ols, were prepared from epichlorohydrin and aliphatic alcohols with alkyl chain lengths of 9-16 carbon atoms. Tryptophan was then attached to the monosubstituted glycerol backbone from its α-amino group through an α-NH-C bond. Structural assignment of the new compounds was made on the basis of elemental analysis and spectroscopic data. Critical micelle concentrations of the new surfactants, as well as the negative logs of the surfactant concentrations required to reduce the surface tension of the solvent by 20 mN/m (pC20) and the interfacial areas occupied by the surfactant molecules, were calculated from aqueous surface tension measurements using the Wilhelmy plate technique.