Esters

Overview

Carboxylic acid derivatives containing a C(O)-O-R group.

Esters are carboxylic acid derivatives that undergo hydrolysis; the groups on both sides of the ester linkage determine the products.

An ester joins an acyl group through oxygen to an organic group. Hydrolysis cleaves the ester linkage, returning an alcohol or phenol and an acid or carboxylate. Track both fragments: distinguish the acyl side from the group attached through oxygen.

Identifiers

Functional group

COO

Also known as

ester

Properties

Hydrolysis comparison

Acid-catalysed hydrolysis is reversible; alkaline hydrolysis produces a carboxylate and consumes hydroxide.

Polymer connection

Repeated ester linkages connect diol and diacid building blocks in polyesters; a single ester molecule is not itself a polymer.

Related compounds

• Methyl methacrylate

  An unsaturated ester that forms acrylic polymer PMMA.

• Dimethyl terephthalate

  An alternative PET feedstock used together with ethylene glycol.

• Vinyl acetate

  The acetate-bearing comonomer used with ethene to make EVA.

• Lactide

  The ring-shaped monomer in the selected PLA route.

• Methyl acetate

  Methyl ethanoate, an ester with different methyl environments.

• Ethyl acetate

  Ethyl ethanoate, a simple ester connecting alcohol and carboxylic-acid chemistry.

• Propyl acetate

  Propyl acetate is an organic compound with the molecular formula C5H10O2.

• Butyl acetate

  Butyl acetate is an organic compound with the molecular formula C6H12O2.

• Isopentyl acetate

  Isopentyl acetate is an organic compound with the molecular formula C7H14O2.

• Ethyl butyrate

  Ethyl butyrate is an organic compound with the molecular formula C6H12O2.

• Methyl benzoate

  Methyl benzoate is an organic compound with the molecular formula C8H8O2.

• Ethyl benzoate

  An ester joining a benzoyl fragment to an ethoxy group.

• Aspirin

  Acetylsalicylic acid: an ester and a carboxylic acid in the same molecule.

• Benzocaine

  Benzocaine is an organic compound with the molecular formula C9H11NO2.

• Methyl salicylate

  An aromatic ester that retains a separate phenolic hydroxyl group.

• Methyl methanoate

  The simplest methyl ester, combining a methanoyl group with methoxy oxygen.

• Ethyl methanoate

  A methanoate ester whose oxygen-bound group is ethyl.

• Methyl propanoate

  An ester with a propanoyl fragment and an oxygen-bound methyl group.

• Ethyl propanoate

  An ester joining the propanoic-acid and ethanol carbon frameworks.

• Phenyl ethanoate

  An aryl ester in which phenyl is bonded through oxygen to an acetyl group.

Connected reactions

• Esterification: Carboxylic acids → Esters

  Carboxylic acids react with alcohols to form esters.

• Esterification co reactant: Alcohols → Esters

  Alcohols combine with carboxylic acids to form esters.

• Hydrolysis: Esters → Carboxylic acids

  Hydrolysis converts esters back into carboxylic acid products.

• Hydrolysis co product: Esters → Alcohols

  Hydrolysis of an ester also regenerates the alcohol component.

• Acylation: Acyl chlorides → Esters

  Alcohol acylation converts acyl chlorides into esters.

• Anhydride alcoholysis: Acid anhydrides → Esters

  Alcohol oxygen attacks an anhydride carbonyl and the tetrahedral intermediate expels carboxylate. Proton transfer produces the ester and a carboxylic acid; one acyl fragment transfers to the alcohol.

References

1. Organic Chemistry: Chemistry of EstersJohn McMurry · OpenStax Organic Chemistry · 2023

   Distinguishes reversible acid-catalysed ester hydrolysis from alkaline saponification, which gives a carboxylate ion until a separate acidification step.

2. Manufacturing acrylic glass from MMAPLEXIGLAS / POLYVANTIS
3. Polyesters: manufacture and usesChemical Industry Education Centre, University of York
4. Vinyl acetate monomerCelanese
5. Lactides: cyclic diesters of lactic acidNatureWorks
6. PubChem Compound Summary: Methyl acetate (CID 6584)National Center for Biotechnology Information · PubChem

   Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.

7. PubChem Compound Summary: Ethyl acetate (CID 8857)National Center for Biotechnology Information · PubChem

   Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.

8. PubChem Compound Summary: Propyl acetate (CID 7997)National Center for Biotechnology Information · PubChem

   Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.

9. PubChem Compound Summary: Butyl acetate (CID 31272)National Center for Biotechnology Information · PubChem

   Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.

10. PubChem Compound Summary: Isopentyl acetate (CID 31276)National Center for Biotechnology Information · PubChem

    Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.

11. PubChem Compound Summary: Ethyl butyrate (CID 7762)National Center for Biotechnology Information · PubChem

    Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.

12. PubChem Compound Summary: Methyl benzoate (CID 7150)National Center for Biotechnology Information · PubChem

    Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.

13. PubChem Compound Summary: Ethyl benzoate (CID 7165)National Center for Biotechnology Information · PubChem

    Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.

14. PubChem Compound Summary: Aspirin (CID 2244)National Center for Biotechnology Information · PubChem

    Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.

15. PubChem Compound Summary: Benzocaine (CID 2337)National Center for Biotechnology Information · PubChem

    Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.

16. PubChem Compound Summary: Methyl salicylate (CID 4133)National Center for Biotechnology Information · PubChem

    Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.

17. PubChem Compound Summary: Methyl methanoate (CID 7865)National Center for Biotechnology Information · PubChem

    Identity, molecular formula, molecular weight and selected English aliases retrieved via PUG REST on 2026-09-16. Chinese search names are curated nomenclature translations. Unspecified stereochemistry remains unspecified.

18. PubChem Compound Summary: Ethyl methanoate (CID 8025)National Center for Biotechnology Information · PubChem

    Identity, molecular formula, molecular weight and selected English aliases retrieved via PUG REST on 2026-09-16. Chinese search names are curated nomenclature translations. Unspecified stereochemistry remains unspecified.

19. PubChem Compound Summary: Methyl propanoate (CID 11124)National Center for Biotechnology Information · PubChem

    Identity, molecular formula, molecular weight and selected English aliases retrieved via PUG REST on 2026-09-16. Chinese search names are curated nomenclature translations. Unspecified stereochemistry remains unspecified.

20. PubChem Compound Summary: Ethyl propanoate (CID 7749)National Center for Biotechnology Information · PubChem

    Identity, molecular formula, molecular weight and selected English aliases retrieved via PUG REST on 2026-09-16. Chinese search names are curated nomenclature translations. Unspecified stereochemistry remains unspecified.

21. PubChem Compound Summary: Phenyl ethanoate (CID 31229)National Center for Biotechnology Information · PubChem

    Identity, molecular formula, molecular weight and selected English aliases retrieved via PUG REST on 2026-09-16. Chinese search names are curated nomenclature translations. Unspecified stereochemistry remains unspecified.