Home --> Products --> Biodiesel Basics --> Biodiesel Production --> Biodiesel Process
Biodiesel (methyl esters) is produced from oils through a chemical process called transesterification. For example, vegetable oil is composed of three fatty acid molecules linked to a glycerol molecule to form triglycerides. When combined with an alcohol in the presence of a catalyst such as sodium hydroxide, the glycerine molecule is stripped from the fatty acids and alkyls esters (biodiesel) and glycerin are formed.
The diagram below shows some of the steps in the process. Note that glycerin is the other by-product of the transesterification reaction (not shown in the diagram). Glycerin must be disposed or processed further for other possible uses. Crude oils or waste oils must be pre-treated because they contain larger amounts of free fatty acids (FFA) which interfere with the main reaction and may result in the inability to generate biodiesel.