Role of Internal Pressure-Free Volume in the Study of Calorific Value of Vegetable Oils as Biodiesel

Many studies have been made on physio-chemical properties of several vegetable oils. However, the thermodynamic properties such as internal pressure and free volume and their relation to fuel characteristics like higher heating value and Cetane number have not been made so far and are reported for the first time. The nature of the internal molecular structure and its impact on the physical and thermodynamic properties is studied and reported. Though oils have a very complex structure, their physio-chemical properties mainly depend on the average chain length of fatty acids and their level of saturation.