Thermodynamic properties of N,N-dimethylformamide and N,N-dimethylacetamide

The heat capacity of N,N-dimethylformamide and N,N-dimethylacetamide in both crystalline and liquid state was determined between T = (7 to 305) K and T = (7 to 340) K, respectively, by adiabatic vacuum calorimetry, generally with an uncertainty of ±0.2%. The melting temperatures and the enthalpies of fusion were measured and the entropies of fusion were estimated. The experimental data were used to calculate the standard (p^{{ring operator}} = 0.1 MPa) thermodynamic functions of the examined amides C_p,m^{{ring operator}} / R, Δ_o^T H_m^{{ring operator}} / R, Δ_o^T S_m^{{ring operator}} / R, and Φ_m^{{ring operator}} = Δ_o^T S_m^{{ring operator}} - Δ_o^T H_m^{{ring operator}} / T (where R is the universal gas constant) in the range from T → 0 to T = 305 (340) K.