Biodiesel
Biodiesel
- Biodiesel is made from renewable vegetable oils rather than non sustainable petrochemicals
- Natural triglyceride oils are converted to esters of methanol, which makes them less viscous
- Biodiesel made from rapeseed oil for example is produced by transesterification
- The triglyceride is converted, or transesterified, into the less viscous fatty acid methyl ester (FAME) using methanol
- Acids and alkalis can both be used to catalyse the reaction
- An acid works by protonating the carbonyl group
- An alkali works by deprotonating the alcohol / methanol
- However, it is more common to use an alkaline catalyst such as NaOH / KOH
- The transesterification is reversible, so an excess of methanol is used to drive the equilibrium to the right
- Under optimum conditions this process can produce a very successful yield of 98%
Transesterification forming methyl esters
