Acid hydrolysis

Overview

Water adds to the protonated ester carbonyl. Proton transfer allows methanol to leave as the carbonyl reforms, producing the acid and alcohol together.

Transformation

Methyl acetate → Methanol

Equation

CH3COOCH3 + H2O <=> CH3COOH + CH3OH

Reactants

Methyl acetate + Water

Products

Ethanoic acid + Methanol

Reagents

Water; dilute acid catalyst

Environment

Heat in aqueous acid; reversible hydrolysis

Reaction class

Acid hydrolysis

Mechanism

acid-catalysed ester hydrolysis

Evidence level

source-backed molecular example

Scope and limitations

Scope

Methyl acetate yields both ethanoic acid and methanol.

Limitations

The two product branches describe one reaction. Alkaline hydrolysis would instead produce an ethanoate salt until acid work-up.

Related reactions

• Catalytic oxidation: Methanol → Methanal

  Removing hydrogen from methanol creates a carbonyl while retaining its single carbon. Oxygen accepts the removed hydrogen as water in this overall catalytic-oxidation equation.

• Carbonyl reduction: Methanal → Methanol

  Hydride addition forms a new C-H bond and converts the C=O pi bond into an alkoxide. Protonation then gives methanol without introducing another carbon.

• Esterification: Methanol → Methyl acetate

  Methanol attacks an acid-activated carbonyl; proton transfers and water loss give methyl acetate. The ester oxygen linking to the methyl group comes from the alcohol.

• Acid hydrolysis: Methyl acetate → Ethanoic acid

  Water adds to the protonated ester carbonyl. Proton transfer allows methanol to leave as the carbonyl reforms, producing the acid and alcohol together.

References

1. Organic Chemistry: Chemistry of EstersJohn McMurry · OpenStax Organic Chemistry · 2023

   Distinguishes reversible acid-catalysed ester hydrolysis from alkaline saponification, which gives a carboxylate ion until a separate acidification step.