Oxidation

Overview

Oxidation of an aldehyde gives a carboxylic acid.

Transformation

Aldehydes → Carboxylic acids

Equation

R-CHO + [O] -> R-CO2H

Reagents

acidified K2Cr2O7

Environment

heat under reflux

Reaction class

oxidation

Mechanism

oxidation

Evidence level

textbook core

Scope and limitations

Scope

Aldehydes can be oxidised to carboxylic acids.

Limitations

Ketones are outside this oxidation route under these standard conditions.

Related reactions

• Cyanohydrin formation: Aldehydes → Hydroxynitriles

  Cyanide addition to an aldehyde forms a hydroxynitrile, giving a carbonyl-route analogue of the nitrile chain-extension motif.

• Oxidation: Alcohols → Aldehydes

  Controlled oxidation of a primary alcohol gives an aldehyde.

• Oxidation: Alcohols → Carboxylic acids

  Full oxidation of a primary alcohol gives a carboxylic acid.

• Controlled oxidation: Primary alcohols → Aldehydes

  Controlled oxidation of a primary alcohol gives an aldehyde.

• Complete oxidation: Primary alcohols → Carboxylic acids

  Full oxidation of a primary alcohol gives a carboxylic acid.

• Reduction: Aldehydes → Primary alcohols

  Reduction of an aldehyde gives a primary alcohol.

• Reduction: Carboxylic acids → Primary alcohols

  Reduction of a carboxylic acid gives a primary alcohol.

• 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 addition co reactant: Aldehydes → Secondary alcohols

  Aldehydes plus Grignard reagents give secondary alcohols after acidic work-up.

References

1. 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.