Thermodynamics of mixtures containing alkoxyethanols. Part XXV. Densities, excess molar volumes and speeds of sound at 293.15, 298.15 and 303.15 K, and isothermal compressibilities at 298.15 K for 2-alkoxyethanol + 1-butanol systems

Densities, ρ, and speeds of sound, u, of systems formed by 2-methoxyethanol (2ME), 2-ethoxyethanol (2EE), 2-propoxyethanol (2PE), or 2-butoxyethanol (2BE) and 1-butanol have been measured at 293.15, 298.15 and 303.15 K and atmospheric pressure using a vibrating tube densimeter and sound analyser Anton Paar model DSA-5000. The ρ and u values were used to calculate excess molar volumes, VE, at those temperatures and deviations from the ideal behaviour of the thermal expansion coefficient, ΔαP, or of the isentropic and isothermal compressibilities, ΔκS and ΔκT at 298.15 K. From the data, it is apparent that the interactional contribution to VE is more important for systems with 2ME or 2EE, while structural effects are more relevant in the 2PE or 2BE mixtures, and that dipolar interactions decrease with the size of the 2-alkoxyethanol. Several methods are applied to predict speeds of sound: free length theory (FLT), collision factor theory (CFT), and Nomoto, Junjie and Van Dael equations. CFT and Nomoto's equation provide the better predictions. Finally, 1-butanol + 2-alkoxyethanol, or + 2-(2-alkoxyethoxy)ethanol mixtures have been studied using ERAS. Poorer results were obtained for systems including 2-(2-alkoxyethoxy)ethanols, which may be due to dipolar interactions and structural effects are more important in such solutions.