The term ‘‘bio’’ indicates the
biological source of biodiesel, in contrast with conventional diesel [9]. Biodiesel is a
clear liquid with a light- to dark-yellow colour. It has a boiling point of over 200 1C, a flash
point between
145–175 1C, a distillation range of 195–325 1C, and a vapour pressure (mm Hg at 22 1C)
less than 5. It is also insoluble in