Nomenclature of Carboxylic Acids

Naming carboxylic acids is straightforward.
 

  • If the compound (or the primary carbon skeleton) is acyclic, name the alkane for the system that would exist if the carboxylic acid were a CH3 group.  Then drop the terminal -e and substitute -oic acid.  The carbon in the carboxylic acid group is always carbon 1 (this may make the numbering different from that of the alkane).

Naming 7-ethyl-4-methylundecanoic acid

  • If another structural feature overrides the carboxylic acid (e.g., a ring), the suffix -carboxylic acid is added to a root name taken by excluding the carboxylic acid carbon.  Again, the carboxylic acid defines the numbering, but now C-1 is the carbon bearing the COOH group.

Naming cis-3-methylcyclohexanecarboxylic acid

There are a number of carboxylic acids for which the common name has been accepted by IUPAC:

Common names. See McMurray, Table 20.1

Salts of carboxylic acids are named using the positive ion, then the name of the acid modified by dropping -oic and adding -ate.

Thus, acetic acid forms a salt sodium acetate, Na+CH3CO2-.