Densities of Dilute Aqueous Solutions of 1-Butanol and 1-Pentanol at Atmospheric Pressure and Temperatures in the Range of 283.15 to 353.15 K

Mass densities of dilute aqueous solutions of 1-butanol and 1-pentanol (with alcohol concentrations between 0.07 to 0.7 and 0.006 to 0.06 mol.kg(-1), respectively) were determined at atmospheric pressure and temperatures in the range of 283.15 to 353.15 K using a custom-built volume dilatometer. The dilatometer was first calibrated using water, and it was then benchmarked using water and aqueous solutions of ethanol. Evaporation in the experiments with water and the alcohol solutions was prevented by adding a small amount of oil (about 0.2 mL) over the liquid surface that was exposed to the ambient air. The density data complement and extend those available in the published literature. They also show that at alcohol concentrations less than 0.01 mol.kg(-1), the density of such solutions may be reasonably assumed to be the same as that of water or calculated using the ideal-solution assumption. For solutions with higher alcohol concentrations, however, the aforementioned assumptions are inappropriate, as they lead to density values that differ from the data presented in this paper by amounts that exceed the expanded uncertainty of the underlying measurements.