The partial molar heat capacities and volumes of some N-acetyl amino acid amides in aqueous solution over the temperature range 288.15 to 328.15 K

Abstract

The partial molar heat capacities, Cp,20, and partial molar volumes, V20, at infinite dilution have been determined for the compounds N-acetylvalinamide and N-acetylleucinamide in aqueous solution at the temperatures 288.15, 298.15, 313.15 and 328.15 K and for N-acetylglycinamide and N-acetylalaninamide at the temperatures 288.15, 313.15 and 328.15 K. Partial molar volumes at infinite dilution have also been determined for the sparingly soluble N-acetylisoleucinamide in aqueous solution over the same temperature range. The Cp,20 and V20 results have been used to calculate amino acid side-chain contributions to the thermodynamic properties. These side-chain contributions are critically compared with those obtained using other model compounds.