Controlled oxidation

Overview

Controlled oxidation of a primary alcohol gives an aldehyde.

Transformation

Primary alcohols → Aldehydes

Equation

R-CH2OH + [O] -> R-CHO + H2O

Reagents

acidified K2Cr2O7

Environment

heat and distil

Reaction class

oxidation

Mechanism

oxidation

Evidence level

textbook core

Scope and limitations

Scope

Primary alcohols are oxidised to aldehydes when the aldehyde is distilled off as it forms.

Limitations

Further oxidation to the acid is avoided by distillation; generic alcohol routes remain as family-level summaries.

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.

• 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.

• Oxidation: Aldehydes → Carboxylic acids

  Oxidation of an aldehyde gives a carboxylic acid.

• Carbonyl addition: Grignard reagents → Primary alcohols

  Grignard addition to methanal gives primary alcohols after work-up.

• Grignard addition co reactant: Methanal → Primary alcohols

  Methanal plus a Grignard reagent gives a primary alcohol 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.