Application of Wada's Group Contribution Method to the Prediction of the Speed of Sound of Biodiesel

Biofuels are an important alternative to environmental sustainability, and biodiesel has a detached contribution to this scenario. The increasing use of biodiesel requires the knowledge of several thermophysical properties of this biofuel. This work addresses the measurements of the speed of sound and density at atmospheric pressure of five fatty acid methyl esters (methyl caprylate, methyl caprate, methyl palmitate, methyl stearate, and methyl linoleate). These data are used to test Wada's group contribution method recently proposed by us and its ability to predict the speed of sound of biodiesel fuels and to expand the application of this model to the prediction of the speed of sound of biodiesel fuels. The overall average relative deviations (OARD) obtained were 0.12% for the methyl esters and 0.29% for biodiesels. An extension of this model to high pressures is also proposed and tested with success, presenting an OARD of 1.0% for six biodiesel fuels.