Abstract
This review treated the researches regarding the effect of counter ion on some physicochemical properties of N-acyl amino acid salts, which has the discrimination between its optically active isomer and racemate. Firstly it was shown that the Krafft temperature of vacyl amino acid salt increased with decreasing size of the amino acid residue and counter ion except for the case of acyl phenylalanineate. It was also found from these results that the L-L interaction in solid state of N-acyl amino acid surfactant salt was superior to the D-L interaction for both the alanine and valine systems when the counter ion size increased. Secondly a diastereomer-type surfactant, which was an amino acid surfactant having optically active base as a counter ion, was investigated. The functions of N-acyl amino acids and PEA as an optical resolving agent were examined by drawing the phase diagrams of some diastereomer mixtures. Finally an unique aggregation behavior of potassium N-acyl phenylalaninate in dilute aqueous solution was explained. It was found that relatively large aggregates were appeared in these system at lower concentration. The large aggregates were not observed in these sodium salts systems. It was found, furthermore, that the unique aggregation behavior has never happened in the case which the racemic modification was employed as acyl phenylalanine.
