Aldehyde oxidation
The hydrated aldehyde is oxidised to a carboxyl group. All four starting carbon atoms remain together in butanoic acid.
- Reagents
- Acidified K2Cr2O7
- Conditions
- Warm in aqueous acid
- Reaction class
- Aldehyde oxidation
- Equation
- CH3CH2CH2CHO + [O] -> CH3CH2CH2COOH
Overview
The hydrated aldehyde is oxidised to a carboxyl group. All four starting carbon atoms remain together in butanoic acid.
Transformation
- Equation
- CH3CH2CH2CHO + [O] -> CH3CH2CH2COOH
- Reagents
- Acidified K2Cr2O7
- Environment
- Warm in aqueous acid
- Reaction class
- Aldehyde oxidation
- Mechanism
- aldehyde oxidation through a hydrate
- Evidence level
- source-backed molecular example
Scope and limitations
- Scope
- The aldehyde carbon becomes the carboxyl carbon.
- Limitations
- Alkaline oxidation gives butanoate before acid work-up.
Related reactions
- Controlled oxidation: Butan-1-ol → Butanal
Oxidation removes hydrogen from the O-H bond and the OH-bearing carbon to form C=O. Separating butanal as it forms limits its further oxidation.
- Carbonyl reduction: Butanal → Butan-1-ol
Hydride adds to the aldehyde carbon and the carbonyl oxygen becomes an alkoxide. Protonation completes the return to butan-1-ol.
- Esterification: Butanoic acid → Ethyl butyrate
Ethanol oxygen bonds to the acid carbonyl carbon, followed by proton transfer and water loss. The product joins a butanoyl fragment to an ethoxy group.
- Acid hydrolysis: Ethyl butyrate → Butanoic acid
Water attack and proton transfers permit the ethoxy fragment to leave as ethanol. Re-forming the carbonyl produces butanoic acid on the other branch.
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.