Densities, Refractive Indices, and Ultrasonic Speeds of N,N-dimethylformamide plus Acetone Binary Mixtures at Different Temperatures

Experimental densities, rho, refractive indices, n, and ultrasonic speeds, u, at various compositions and at various temperatures from (298.15 to 313.15) K for N,N-dimethylformamide + acetone binary mixtures were measured. From these results excess molar volumes (V-m(E)), deviations in refractive indices (Delta n), isentropic compressibilities (Delta k(s)), partial molar volumes ((V) over bar (0)(phi,2)), and partial molar compressibilities ((K) over bar (0)(phi,2)), of acetone in N, N-dimethylformamide were calculated. All the excess and deviation functions were fitted to Redlich-Kister polynomial equation to determine the fitting coefficients and the standard deviations. The values of V-m(E) and Delta k(s) showed negative deviations, whereas excess Delta n showed positive values over the entire range of concentrations and temperatures. The observed variations of these parameters, with concentration and temperature are discussed in terms of the intermolecular interactions and structural effects between the unlike molecules of the binary mixtures.