The calorimetric and volumetric properties of selected alpha-amino acids and alpha,omega-amino acids in water at T = (288.15, 298.15, 313.15, and 328.15) K and p=0.1 MPa

摘要

Relative densities and relative massic heat capacities have been measured for the amino acids beta-alanine, 4-aminobutanoic acid, d,l-norleucine and d,l-norvaline in dilute aqueous solution at p = 0.1 MPa and T = (288.15, 298.15, 313.15 and 328.15) K. Apparent molar volumes and apparent molar heat capacities have been calculated and the isothermal concentration dependences of these properties have been modeled to yield apparent molar properties at infinite dilution. Values for apparent molar properties at infinite dilution are compared to those previously reported in the literature. Trends in the temperature dependences of the infinite dilution properties are discussed in terms of methylene group contributions and the variations in these contributions caused by the presence of ionic end groups.