Fatty Acids and Their Esters

Fatty Acids and Their Esters

• The naturally occurring fats and oils are triesters formed
between glycerol and fatty acids.
• Saturated fatty acid: A long-chain carboxylic acid containing
only carbon–carbon single bonds.
• Unsaturated fatty acid: A long-chain carboxylic acid
containing one or more carbon–carbon double bonds.
• If double bonds are present in naturally occurring fats and
oils, the double bonds are usually cis rather than trans.
Polyunsaturated fatty acids have more than one C=C double
bond. Linoleic and linolenic acids are essential in the human
diet because the body does not synthesize them and they are
needed for the synthesis of other lipids.
The simplest fatty acid esters in nature are waxes. A wax is a
mixture of fatty acid—long-chain alcohol esters. The acids
usually have an even number from 16 to 36 carbons, whereas
the alcohols have an even number from 24 to 36 carbons.
A component in
beeswax is the
ester formed from
a 30-C alcohol
(triacontanol) and
a 16-C acid
(palmitic acid).