Figure 1.10. Naming Carboxylic Acids
The carboxylic acid group does not receive a number in the name because it is a terminal functional
group; common names are included in parentheses.MCAT EXPERTISE
Did you notice that some of the common names are similar between aldehydes and
carboxylic acids? Remembering that formaldehyde and formic acid both refer to molecules
with methane as a parent alkane—and that acetaldehyde and acetic acid contain ethane as a
parent alkane—will help consolidate this information.The carboxylic acid derivatives are the final category of functional groups. These include esters,
amides, and anhydrides.
ESTERS
Esters are common carboxylic acid derivatives. In these compounds, the hydroxyl group (–OH) is
replaced with an alkoxy group (–OR, where R is a hydrocarbon chain). Ester nomenclature is based
on the naming conventions for carboxylic acids. The first term is the alkyl name of the esterifying
group. Think of this first term as an adjective describing the ester, based on the identity of the alkyl
(R) group. The second term is the name of the parent acid, with –oate replacing the –oic acid suffix.
For example, methanoic acid (formic acid) would form butyl methanoate with exposure to butanol
under appropriate reaction conditions. Examples of ester nomenclature are shown in Figure 1.11.