Transesterification

Transesterification is a reaction in which an ester’s alcohol-derived group is exchanged with one from another alcohol. It is used to make biodiesel from oils and fats.

Nucleophilic acyl substitution: A reaction in which a nucleophile replaces a group attached to an acyl carbon. Transesterification proceeds through substitution at the ester’s acyl carbon.
Biodiesel: A diesel fuel made from fatty acid esters derived from biological oils or fats. Its fatty acid methyl esters are commonly produced by transesterifying triglycerides.
Ester: An organic compound containing a carbonyl group bonded to an oxygen that is bonded to carbon. Transesterification acts on this functional group by replacing its alcohol-derived portion.
Amidation: A reaction that forms an amide, commonly by coupling an amine with a carboxylic acid derivative. It exchanges or forms acyl derivatives involving nitrogen, unlike alcohol-based ester exchange.
Fischer esterification: An acid-catalyzed reaction of a carboxylic acid with an alcohol to form an ester and water. It forms esters from acids and alcohols rather than exchanging an ester’s alcohol-derived group.
Triglyceride: A lipid consisting of glycerol esterified with three fatty acids. Vegetable oils and animal fats are largely triglycerides used as biodiesel feedstocks.
Alcohol: An organic compound containing a hydroxyl group bonded to a saturated carbon atom. The incoming alcohol supplies the group that replaces the ester’s original alcohol-derived group.
Esterification: A reaction that forms an ester, commonly from a carboxylic acid and an alcohol. It creates an ester bond, whereas transesterification starts with an ester and exchanges its alcohol-derived group.
Acid catalysis: Catalysis in which proton transfer increases the reactivity of a substrate or intermediate. Protonating the carbonyl oxygen makes the ester more susceptible to alcohol attack.
Fatty acid methyl ester: An ester formed from a fatty acid and methanol, often abbreviated FAME. FAME is the principal product when triglycerides react with methanol in biodiesel production.

Linked from 15 pages