CHIRAL INTERACTION IN AQUEOUS-SOLUTIONS OF AMINO-ACIDS - A CALORIMETRIC STUDY OF THE PROTONATED FORMS IN H2O-HCL MIXED-SOLVENTS AT 25-DEGREES-C

The enthalpies of dilution in H2O-HCl mixed solvents containing the protonated forms of α-aminoacids bearing alkyl chains of increasing length (glycine, alanine, aminobutyric acid, valine, norvaline, leucine, isoleucine, norleucine) were measured at 25°C. The dilution enthalpies were the same for solutions containing only one or both the enantiomeric forms of the same aminoacid. The hypothesis of the main role played in pure water by the zwitterions on the possibility of chiral recognition was confirmed. © 1990 Plenum Publishing Corporation.