Enthalpies of Dilution of Acetamide and N,N-Dimethylformamide in Aqueous Sodium Chloride Solutions at 298.15 K

Abstract

The enthalpies of dilution of acetamide and N,N-dimethylformamide (DMF) in pure water and aqueous sodium chloride solutions have been determined using flow microcalorimetry at 298.15 K. The homogeneous enthalpic interaction coefficients (h2, h3, h4) in the range of sodium chloride molality, (0 to 0.6) mol·kg−1, have been calculated according to the McMillan−Mayer theory. It is found that the enthalpic pairwise interaction coefficients h2 of acetamide and DMF are all positive in aqueous sodium chloride solution and become more positive with an increase in the molality of sodium chloride. The value of h2 of acetamide is less than that of DMF in pure water and an aqueous solution of the same sodium chloride molality. The results are discussed in terms of the solute−solute and solute−solvent interactions.