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2.5: Nomenclature of Esters

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  • Learning Objectives

    • Use common names to name esters.
    • Name esters according to the IUPAC system.

    Esters occur widely in nature. Unlike carboxylic acids, esters generally have pleasant odors and are often responsible for the characteristic fragrances of fruits and flowers. Once a flower or fruit has been chemically analyzed, flavor chemists can attempt to duplicate the natural odor or taste. Both natural and synthetic esters are used in perfumes and as flavoring agents.

    Fats and vegetable oils are esters of long-chain fatty acids and glycerol. Esters of phosphoric acid are of the utmost importance to life.

    Names of Esters

    Although esters are covalent compounds and salts are ionic, esters are named in a manner similar to that used for naming salts. The group name of the alkyl or aryl portion is given first and is followed by the name of the acid portion. In both common and International Union of Pure and Applied Chemistry (IUPAC) nomenclature, the -ic ending of the parent acid is replaced by the suffix -ate (Table \(\PageIndex{1}\)). The only difference is the name used for the acid portion: the common nomenclature follows the common names used for acids, while the IUPAC nomenclature applies the official prefixes to indicate numbers of carbon atoms on the main carbon chain.

    Esters nomenclature.png


    Table \(\PageIndex{1}\): Nomenclature of Esters
    Condensed Structural Formula Common Name IUPAC Name
    HCOOCH3 methyl formate methyl methanoate
    CH3COOCH3 methyl acetate methyl ethanoate
    CH3COOCH2CH3 ethyl acetate ethyl ethanoate
    CH3CH2COOCH2CH3 ethyl propionate ethyl propanoate
    CH3CH2CH2COOCH(CH3)2 isopropyl butyrate isopropyl butanoate
    Table 15.3.jpg ethyl benzoate ethyl benzoate

    Example \(\PageIndex{1}\)

    Give the common and IUPAC names for each compound.

    1. Ex 5 1.jpg
    2. Ex 5 2.jpg


    1. The alkyl group attached directly to the oxygen atom is a butyl group (in green).
      Ex 5 Ans 1.jpg

      The part of the molecule derived from the carboxylic acid (in red) has three carbon atoms. It is called propionate (common) or propanoate (IUPAC). The ester is therefore butyl propionate or butyl propanoate.

    2. An alkyl group (in green) is attached directly to the oxygen atom by its middle carbon atom; it is an isopropyl group. The part derived from the acid (that is, the benzene ring and the carbonyl group, in red) is benzoate. The ester is therefore isopropyl benzoate (both the common name and the IUPAC name).
      Ex 5 Ans 2.jpg

    Exercise \(\PageIndex{1}\)

    Give the common and IUPAC names for each compound.

    1. SB 1.jpg
    2. SB 2.jpg

    Example \(\PageIndex{2}\)

    Draw the structure for ethyl pentanoate.


    Start with the portion from the acid. Draw the pentanoate (five carbon atoms) group first; keeping in mind that the last carbon atom is a part of the carboxyl group.

    Ex 6 1.jpg

    Then attach the ethyl group to the bond that ordinarily holds the hydrogen atom in the carboxyl group.

    Ex 6 2.jpg

    Exercise \(\PageIndex{2}\)

    Draw the structure for phenyl pentanoate.

    Concept Review Exercises

    1. From what carboxylic acid and what alcohol can isopropyl hexanoate be made?
    2. From what carboxylic acid and what alcohol can cyclobutyl butyrate be made?


    1. hexanoic acid and isopropyl alcohol
    2. butyric acid and cyclobutyl alcohol

    Key Takeaway

    • An ester has an OR group attached to the carbon atom of a carbonyl group.


    1. Draw the structure for each compound.

      1. methyl acetate
      2. ethyl pentanoate
      3. phenyl acetate
      4. isopropyl propionate
    2. Draw the structure for each compound.

      1. ethyl hexanoate
      2. ethyl benzoate
      3. phenyl benzoate
      4. ethyl 3-methylhexanoate
    3. Name each compound with both the common name and the IUPAC name.

      1. Ex 3a.jpg
      2. Ex 3b.jpg
    4. Name each compound with both the common name and the IUPAC name.

      1. Ex 4a.jpg
      2. Ex 4b.jpg


      1. Ans 1a.jpg
      2. Ans 1b.jpg
      3. Ans 1c.jpg
      4. Ans 1d.jpg
      1. methyl formate; methyl methanoate
      2. ethyl propionate; ethyl propanoate

      Citations and attributions

      Esters - Structures and Names. (2020, August 17). Retrieved May 22, 2021, from