Surface Tensions of Biodiesels at Various Temperatures and Pressures with Gibbs Energy Additivity Approach

Surface tension is an important physical property of biodiesel. It is directly affected by both temperature and
pressure. Gibbs free energy additivity is used as an alternative approach to quantitative structure-property relationship (QSPR) in estimating surface tension at high temperature and pressure which correlate surface tension of biodiesels to their carbon numbers, number of double bonds of fatty acid are proposed. The estimation results of surface tension of biodiesel as well as canola, jatropha and soapnut biodiesel fuels at various temperatures and pressures up to 473 K and 7 MPa which the most accurate predictive model. The surface tension of biodiesel fuels showed a linear relationship with Gibbs energy additivity approach. The model was proposed to estimate surface tension at high pressure and developed using the measured data from the tests for each liquid fuel.