Densities and surface tensions of binary mixtures of biodiesel, diesel, and n-butanol

Density and surface tension have been measured for mixtures of biodiesel+ n -butanol, biodiesel+diesel, and diesel+ n -butanol over the entire concentration range at 283.15 K and 293.15 K and atmospheric pressure, with the combined expanded uncertainties of 1.32 kg·m −3 and 1%, receptively. Densities were determined by a single-sinker densimeter; surface tensions were measured using the surface laser light scattering method. The experimental data showed that densities and surface tensions decreased as temperature increased. The excess surface tensions and excess densities were all negative, and further fitted to the Redlich-Kister equation.