Enthalpy of dilution of aliphatic amides in aqueous solutions at temperatures between 293.15 K and 308.15 K

Abstract

The enthalpies of dilution of aqueous solutions of acetamide, propionamide and butyramide were determined as a function of the molar fraction at 293.15 K, 298.15 K, 303.15 K and 308.15 K by flow microcalorimetric measurements. The enthalpies of dilution of amides are compared with literature data when available and the results are discussed in terms of solute–solvent interactions. The enthalpic interaction coefficients were obtained according to the McMillan–Mayer theory. The addition of a CH 2 group causes an important change in the interaction coefficients. The pairwise coefficients increase as the number of CH 2 groups increase. Two additivity approaches are used in this work: the Savage–Wood principle and a simple methylene additivity approach. The results obtained by both methods are presented and compared with literature data.