Enthalpies of dilution and volumetric properties of N,N′-hexamethylenebisacetamide in aqueous solutions of sodium chloride at 298.15 K

Enthalpies of dilution (Delta H-dil(m)) of N,N'-hexamethylenebisacetamide (HMBA) in aqueous solutions of sodium chloride (NaCl) were determined at 298.15 K by isothermal titration microcalorimetry. Densities (rho) of the ternary homogeneous systems were also measured with a quartz vibrating-tube densimeter. The homogeneous enthalpic interaction coefficients have been calculated according to the excess enthalpy concept based on the calorimetric data. Apparent molar volumes (V-phi) of the ternary systems were calculated from the data of densities, which have been used to deduce limiting partial molar volumes of HMBA (V-phi(0)) and limiting partial molar volumes of transfer (Delta V-trs(phi)0) from water to sodium chloride solutions at different concentrations. The results are discussed in terms of weak interactions of the diluted component with other species. (C) 2010 Elsevier Ltd. All rights reserved.