Thermochemical analysis of intermolecular interactions between N-acetylglycine and polyols in aqueous solutions

Abstract

The integral enthalpies of dissolution Δ_solH_m for N-acetylglycine in aqueous solutions of glycerol, ethylene glycol and 1,2-propylene glycol are measured via solution calorimetry. The standard enthalpies of dissolution (Δ_solН⁰) and transfer (Δ_trН⁰) for N-acetylglycine from water to aqueous solutions of polyhydric alcohols are calculated from experimental data. Positive values of enthalpy coefficients of pair interactions h_xy for amino acids and polyol molecules are calculated using the McMillan–Mayer theory. The results are discussed using an approach for evaluating different types of interactions in ternary systems and the effect the structural features of interacting biomolecules have on the thermochemical characteristics of N-acetylglycine dissolution.