Illustrated Glossary of Organic Chemistry

Biodiesel: Diesel fuel composed of a mixture of fatty acid methyl esters, synthesized by transesterification of triacylglycerides from waste cooking oil, vegetable oils, etc. 'Biodiesel' refers to the vegetable oil or animal fat origin of the triacylglyceride starting material.

Biodiesel is synthesized by transesterification of triacylglycerides in vegetable oil or animal fat. In this example, glycerol tristearate is transesterified with methanol and either base catalysis (with CH₃O^-) or acid catalysis (for example with H₂SO₄) to produce methyl stearate (the product used for biodiesel fuel) plus glycerol. The transesterification reaction follows the nucleophilic carbonyl substitution mechanism.


The biodiesel fuel used in this bus was produced from soybean oil.