Physical Properties of Biodiesel Blended with Hexanol Isomers at Different Temperatures: Surface Tension, Density, Viscosity, and Refractive Index

In this work, surface tensions, densities, viscosities, and refractive indices of biodiesel +1-hexanol, 4-methyl-2-pentanol, and 2-ethyl-1-butanol have been measured from 288.15 to 338.15 K at 0.1 MPa throughout the whole composition range. Du Nouy ring tensiometer, vibrating tube densimeter, glass capillary viscosimeter, and Abbemat refractometer are used to measure the surface tensions, densities, viscosities, and refractive indices, respectively. Our experimental results for the pure alcohols agree with literature values within average absolute percentage deviations of 1.171, 0.024, 0.737, and 0.061 % for the surface tension, density, viscosity, and refractive index, respectively. Experimental densities and viscosities of some of our biodiesel mixtures satisfy the limits set by the diesel fuel standard (EN 590), becoming potential substitutes of conventional diesel. Kinematic viscosities show a minimum value at alcohol mass fractions between 0.4 and 0.9. Thermodynamic properties and derived properties have been correlated using different equations reported in the literature.