Apparent molar volumes and expansibilities of H2O and D2O in N,N-dimethylformamide and N,N-dimethylacetamide in the range of T = (278.15 to 318.15) K at p = 0.1 MPa: A comparative analysis

Densities of highly dilute solutions of protiated and deuterated water in N,N-dimethylformamide and N,N-dimethylacetamide, with the solute mole fractions ranging up to 0.012, were measured with an error of 1.0 · 10−5 · cm3 · mol−1 at T = (278.15, 288.15, 298.15, 308.15 and 318.15) K and atmospheric pressure using a precise sealed vibrating-tube densimeter. Apparent molar volumes and apparent molar isobaric expansibilities (down to the infinite dilution) of water isotopologues were calculated. The temperature-dependent behavior of D2OH2O solute isotope effects on the apparent molar quantities under study were described taking into account the structural features of the amide-solvating media compared.

► Densities of highly dilute solutions of H2O and D2O in DMF and DMA were measured. ► Apparent molar volumes and expansibilities for water isotopologues were computed. ► Water dissolved in DMA forms denser structure packings compared with those in DMF. ► Apparent molar expansibilities of both H2O and D2O in DMA are higher than in DMF. ► The apparent volume is lower but apparent expansibility is higher for solute D2O.