Densities, Refractive Indices, Ultrasonic Speeds and Excess Properties of Acetonitrile + Poly(ethylene glycol) Binary Mixtures at Temperatures from 298.15 to 313.15 K

Abstract

The densities, ρ, refractive indices, n D, and ultrasonic speeds, u, of binary mixtures of acetonitrile (AN) with poly(ethylene glycol) 200 (PEG200), poly(ethylene glycol) 300 (PEG300) and poly(ethylene glycol) 400 (PEG400) were measured over the entire composition range at temperatures (298.15, 303.15, 308.15 and 313.15) K and at atmospheric pressure. From the experimental data, the excess molar volumes, $$ V_{\text{m}}^{\text{E}} $$ , deviations in refractive indices, $$ \Delta n_{\text{D}} $$ , excess molar isentropic compressibility, $$ K_{{s , {\text{m}}}}^{\text{E}} $$ , excess intermolecular free length, $$ L_{\text{f}}^{\text{E}} $$ , and excess acoustic impedance, Z E, have been evaluated. The partial molar volumes, $$ \overline{V}_{\text{m,1}} $$ and $$ \overline{V}_{\text{m,2}} $$ , partial molar isentropic compressibilities, $$ \overline{K}_{{s , {\text{m,1}}}} $$ and $$ \overline{K}_{{s , {\text{m,2}}}} $$ , and their excess values over whole composition range and at infinite dilution have also been calculated. The variations of these properties with composition and temperature are discussed in terms of intermolecular interactions in these mixtures. The results indicate the presence of specific interactions among the AN and PEG molecules, which follow the order PEG200 < PEG300 < PEG400.