Reduction

Overview

Reduction of a carboxylic acid gives a primary alcohol.

Transformation

Carboxylic acids → Primary alcohols

Equation

R-CO2H + 4[H] -> R-CH2OH + H2O

Reagents

LiAlH4

Environment

dry ether, then aqueous work-up

Reaction class

reduction

Mechanism

hydride reduction

Evidence level

textbook core

Scope and limitations

Scope

Carboxylic acids can be reduced to primary alcohols with strong hydride reducing agents.

Limitations

This route records the functional-group conversion; strong hydride reagents and aqueous work-up are required.

Related reactions

• 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.

• 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.

• Carbonyl addition: Grignard reagents → Primary alcohols

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

• Carboxylation: Grignard reagents → Carboxylic acids

  Grignard carboxylation gives carboxylic acids after acidic work-up.

• Grignard addition co reactant: Methanal → Primary alcohols

  Methanal plus a Grignard reagent gives a primary alcohol 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.

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.