Cyclic esters are called lactones and are named in the same manner as lactams, with the name of
the precursor acid molecule also included. Examples are shown in Figure 9.5.
Figure 9.5. Examples of LactonesBecause they lack hydrogen bonding, esters usually have lower boiling points than their related
carboxylic acids.
Triacylglycerols, the storage form of fats in the body, are esters of long-chain carboxylic acids (fatty
acids) and glycerol (1,2,3-propanetriol). Saponification is the process by which fats are hydrolyzed
under basic conditions to produce soap; saponification of a triacylglycerol is shown in Figure 9.6.
Subsequent acidification of the soap regenerates the fatty acids.
Figure 9.6. Saponification of a Triacylglycerol
Treating triacylglycerols with NaOH will produce fatty acid salts (soap) as well as glycerol.Anhydrides
Anhydrides, also called acid anhydrides, are the condensation dimers of carboxylic acids. These
molecules have the general formula RC(O)OC(O)R. Symmetrical anhydrides are named by
substituting the word anhydride for the word acid in a carboxylic acid. When anhydrides are
asymmetrical, simply name the two chains alphabetically, followed by anhydride, as shown in
Figure 9.7. Phthalic and succinic anhydrides are cyclic anhydrides arising from intramolecular