Carboxylic acids
Carboxylic acids can be reached from nitriles by hydrolysis and can feed amide-bond formation after activation or coupling.
- Functional group
- COOH
- Also known as
- carboxylic acid, alkanoic acids, COOH compounds
Overview
Carbonyl compounds with a carboxyl group used in amide formation.
Carboxylic acids can be reached from nitriles by hydrolysis and can feed amide-bond formation after activation or coupling.
The carboxyl group combines a carbonyl and hydroxyl group. Proton loss gives a resonance-stabilised carboxylate. Acid-base reactions change charge and solubility without changing the carbon skeleton; acyl substitution or reduction makes a different functional group.
Identifiers
- Functional group
- COOH
- Also known as
- carboxylic acid, alkanoic acids, COOH compounds
Chemical identifiers
- SMILES
- CC(=O)O
Properties
- Intermolecular forces
- Carboxylic acids hydrogen-bond and can form dimers; measured physical values belong to individual compounds.
- Salt or derivative
- A carboxylate salt is not an ester: distinguish proton transfer from replacement at the acyl carbon.
Diagnostic tests
carbonate acid test
- Reagent
- sodium carbonate or sodium hydrogencarbonate
- Conditions
- room temperature
- Positive observation
- effervescence of CO2
- Negative observation
- no effervescence
- Interpretation
- Carboxylic acids react with carbonates to release carbon dioxide gas.
- Scope
- Typical qualitative reaction of carboxylic acids.
- Limitations
- Other sufficiently strong acids also release carbon dioxide. Effervescence supports acidity rather than a unique carboxylic-acid identity; confirm the gas if the interpretation depends on it.
- Evidence
- textbook core
Related compounds
- Lactic acid
An upstream feedstock converted into lactide for PLA.
- Methanoic acid
Methanoic acid is an organic compound with the molecular formula CH2O2.
- Ethanoic acid
A weak carboxylic acid linking neutralisation, buffers and ester formation.
- Propanoic acid
Propanoic acid is an organic compound with the molecular formula C3H6O2.
- Butanoic acid
Butanoic acid is an organic compound with the molecular formula C4H8O2.
- Pentanoic acid
Pentanoic acid is an organic compound with the molecular formula C5H10O2.
- Hexanoic acid
Hexanoic acid is an organic compound with the molecular formula C6H12O2.
- Octanoic acid
Octanoic acid is an organic compound with the molecular formula C8H16O2.
- Decanoic acid
Decanoic acid is an organic compound with the molecular formula C10H20O2.
- Lauric acid
Lauric acid is an organic compound with the molecular formula C12H24O2.
- Palmitic acid
Palmitic acid is an organic compound with the molecular formula C16H32O2.
- Stearic acid
Stearic acid is an organic compound with the molecular formula C18H36O2.
- Benzoic acid
An aromatic carboxylic acid used to connect acid–base extraction with organic structure.
- Oxalic acid
Oxalic acid is an organic compound with the molecular formula C2H2O4.
- Malonic acid
Malonic acid is an organic compound with the molecular formula C3H4O4.
- Succinic acid
Succinic acid is an organic compound with the molecular formula C4H6O4.
- Glutaric acid
Glutaric acid is an organic compound with the molecular formula C5H8O4.
- Maleic acid
Maleic acid is an organic compound with the molecular formula C4H4O4.
- Fumaric acid
Fumaric acid is an organic compound with the molecular formula C4H4O4.
- Phthalic acid
Phthalic acid is an organic compound with the molecular formula C8H6O4.
- Isophthalic acid
Isophthalic acid is an organic compound with the molecular formula C8H6O4.
- Aspirin
Acetylsalicylic acid: an ester and a carboxylic acid in the same molecule.
- Salicylic acid
A molecule with adjacent phenol and carboxylic-acid groups, central to aspirin chemistry.
- Cinnamic acid
Cinnamic acid is an organic compound with the molecular formula C9H8O2.
- Acrylic acid
Acrylic acid is an organic compound with the molecular formula C3H4O2.
- Methacrylic acid
Methacrylic acid is an organic compound with the molecular formula C4H6O2.
- Glycolic acid
Glycolic acid is an organic compound with the molecular formula C2H4O3.
- 2-Methylpropanoic acid
A branched carboxylic acid with the same formula as butanoic acid.
Connected reactions
- Oxidation: Alcohols → Carboxylic acids
Full oxidation of a primary alcohol gives a carboxylic acid.
- Complete oxidation: Primary alcohols → Carboxylic acids
Full oxidation of a primary alcohol gives a carboxylic acid.
- Reduction: Carboxylic acids → Primary alcohols
Reduction of a carboxylic acid gives a primary alcohol.
- Oxidation: Aldehydes → Carboxylic acids
Oxidation of an aldehyde gives a carboxylic acid.
- Hydrolysis: Nitriles → Carboxylic acids
Nitriles can be hydrolysed to carboxylic acids, splitting the old aggregate nitrile-to-amide route into a single functional-group conversion.
- Activation for amide formation: Carboxylic acids → Amide chemistry
Carboxylic acids or activated acid derivatives connect to amide-bond formation.
- Esterification: Carboxylic acids → Esters
Carboxylic acids react with alcohols to form esters.
- Hydrolysis: Esters → Carboxylic acids
Hydrolysis converts esters back into carboxylic acid products.
- Chlorination: Carboxylic acids → Acyl chlorides
PCl5 converts carboxylic acids into acyl chlorides.
- Chlorination with thionyl chloride: Carboxylic acids → Acyl chlorides
Thionyl chloride converts carboxylic acids into acyl chlorides with sulfur dioxide and hydrogen chloride as by-products.
- Hydrolysis: Acyl chlorides → Carboxylic acids
Water hydrolyses acyl chlorides to carboxylic acids, releasing hydrogen chloride.
- Carboxylation: Grignard reagents → Carboxylic acids
Grignard carboxylation gives carboxylic acids after acidic work-up.
- Grignard carboxylation co reactant: Carbon dioxide → Carboxylic acids
Carbon dioxide plus a Grignard reagent gives a carboxylic acid after acidic work-up.
- Salt formation: Carboxylic acids → Carboxylate salts
Carboxylic acids react with bases, carbonates and reactive metals to form carboxylate salts.
- Anhydride hydrolysis: Acid anhydrides → Carboxylic acids
Water attacks an anhydride carbonyl, and collapse of the tetrahedral intermediate breaks the acyl-oxygen linkage. Proton transfer gives carboxylic-acid products; a mixed anhydride yields two different acids.
References
- Organic Chemistry: Structure and Properties of Carboxylic AcidsJohn McMurry · OpenStax Organic Chemistry · 2023
Supports functional-group chemistry used to curate the linked examples. Checked 2026-09-16; named examples are applications of textbook scope, without claimed experimental yields.
- Pearson Edexcel Level 3 Advanced GCE in Chemistry specificationPearson Education Limited · Pearson qualifications · 2024
Supports the textbook-core organic reaction routes used for displayed route and mechanism content.
- Ingeo technology: sugars, lactic acid, lactide and PLANatureWorks
- PubChem Compound Summary: Methanoic acid (CID 284)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- PubChem Compound Summary: Ethanoic acid (CID 176)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- PubChem Compound Summary: Propanoic acid (CID 1032)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- PubChem Compound Summary: Butanoic acid (CID 264)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- PubChem Compound Summary: Pentanoic acid (CID 7991)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- PubChem Compound Summary: Hexanoic acid (CID 8892)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- PubChem Compound Summary: Octanoic acid (CID 379)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- PubChem Compound Summary: Decanoic acid (CID 2969)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- PubChem Compound Summary: Lauric acid (CID 3893)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- PubChem Compound Summary: Palmitic acid (CID 985)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- PubChem Compound Summary: Stearic acid (CID 5281)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- PubChem Compound Summary: Benzoic acid (CID 243)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- PubChem Compound Summary: Oxalic acid (CID 971)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- PubChem Compound Summary: Malonic acid (CID 867)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- PubChem Compound Summary: Succinic acid (CID 1110)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- PubChem Compound Summary: Glutaric acid (CID 743)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- PubChem Compound Summary: Maleic acid (CID 444266)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- PubChem Compound Summary: Fumaric acid (CID 444972)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- PubChem Compound Summary: Phthalic acid (CID 1017)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- PubChem Compound Summary: Isophthalic acid (CID 8496)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- 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.
- PubChem Compound Summary: Salicylic acid (CID 338)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- PubChem Compound Summary: Cinnamic acid (CID 444539)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- PubChem Compound Summary: Acrylic acid (CID 6581)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- PubChem Compound Summary: Methacrylic acid (CID 4093)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- PubChem Compound Summary: Glycolic acid (CID 757)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- PubChem Compound Summary: 2-Methylpropanoic acid (CID 6590)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.