Ketones
Ketones undergo nucleophilic addition with cyanide to form hydroxynitriles, adding a second carbonyl-derived entry route.
- Functional group
- C=O
- Also known as
- alkanones, ketone, carbonyl compounds
Overview
Carbonyl compounds with an internal C=O group.
Ketones undergo nucleophilic addition with cyanide to form hydroxynitriles, adding a second carbonyl-derived entry route.
A ketone has two carbon groups bonded to the carbonyl carbon. Reduction gives a secondary alcohol. Ordinary aldehyde oxidation tests usually leave simple ketones unchanged; this is a condition-dependent contrast, not a claim that ketones can never be oxidised.
Identifiers
- Functional group
- C=O
- Also known as
- alkanones, ketone, carbonyl compounds
Chemical identifiers
- SMILES
- CC(=O)C
Properties
- Oxidation boundary
- Strong oxidative conditions can cleave carbon-carbon bonds; they do not simply give a same-skeleton carboxylic acid.
- Iodoform boundary
- Only the methyl ketone subgroup contains the CH3CO- pattern required for the standard iodoform reaction.
Diagnostic tests
2,4-DNP carbonyl test
- Reagent
- 2,4-DNP
- Conditions
- room temperature
- Positive observation
- orange precipitate
- Negative observation
- no orange precipitate
- Interpretation
- A precipitate supports an aldehyde or ketone functional group; a C=O bond in an ester, acid or amide does not by itself predict this result.
- Scope
- Aldehydes and ketones form 2,4-dinitrophenylhydrazones.
- Limitations
- Aldehydes and ketones give positive responses; compare derivative melting points or spectra.
- Evidence
- textbook core
Related compounds
- Propanone
The simplest ketone, connecting carbonyl addition with secondary-alcohol formation.
- Butan-2-one
An unsymmetrical ketone whose reduction creates a stereogenic centre.
- Pentan-2-one
Pentan-2-one is an organic compound with the molecular formula C5H10O.
- Pentan-3-one
A symmetrical ketone useful for comparing structure and reduction products.
- Cyclopentanone
A five-membered cyclic ketone with two equivalent ring paths at the carbonyl.
- Cyclohexanone
A cyclic ketone that reduces to cyclohexanol.
- Acetophenone
An aromatic methyl ketone with different groups on either side of its carbonyl.
- Benzophenone
A diaryl ketone with two identical phenyl substituents.
- 4-Methylpentan-2-one
4-Methylpentan-2-one is an organic compound with the molecular formula C6H12O.
Connected reactions
- Cyanohydrin formation: Ketones → Hydroxynitriles
Cyanide addition to a ketone forms a hydroxynitrile, adding a second carbonyl route into the expanded organic network.
- Oxidation: Alcohols → Ketones
Oxidation of a secondary alcohol gives a ketone.
- Oxidation: Secondary alcohols → Ketones
Oxidation of a secondary alcohol gives a ketone.
- Reduction: Ketones → Secondary alcohols
Reduction of a ketone gives a secondary alcohol.
- Grignard addition co reactant: Ketones → Tertiary alcohols
Ketones plus Grignard reagents give tertiary alcohols after acidic work-up.
References
- Organic Chemistry: Oxidation of Aldehydes and KetonesJohn 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 International Advanced Level Chemistry Practical GuidePearson Education Limited · Pearson qualifications · 2018
Official Pearson practical guidance for organic qualitative tests, including bromine water, acidified dichromate, silver nitrate, carbonyl reagents and the iodoform reaction.
- 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.
- PubChem Compound Summary: Propanone (CID 180)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- PubChem Compound Summary: Butan-2-one (CID 6569)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- PubChem Compound Summary: Pentan-2-one (CID 7895)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- PubChem Compound Summary: Pentan-3-one (CID 7288)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- PubChem Compound Summary: Cyclopentanone (CID 8452)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- PubChem Compound Summary: Cyclohexanone (CID 7967)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- PubChem Compound Summary: Acetophenone (CID 7410)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- PubChem Compound Summary: Benzophenone (CID 3102)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- PubChem Compound Summary: 4-Methylpentan-2-one (CID 7909)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.