Ester formation

Overview

Ethanol oxygen attacks the acyl carbonyl carbon. Loss of chloride and proton transfer restore C=O and form the ester, with ethanol contributing the ethoxy group and HCl produced in the overall equation.

Transformation

Benzoyl chloride → Ethyl benzoate

Equation

C6H5COCl + CH3CH2OH -> C6H5COOCH2CH3 + HCl

Reactants

Benzoyl chloride + Ethanol

Products

Ethyl benzoate + Hydrogen chloride

Reagents

Ethanol; base to bind HCl

Environment

Dry acylation conditions

Reaction class

Ester formation

Mechanism

nucleophilic addition-elimination

Evidence level

source-backed molecular example

Scope and limitations

Scope

Ethanol supplies the ester ethyl group.

Limitations

The equation shows net HCl production; a base used experimentally forms its corresponding salt.

Related reactions

• Acyl chloride preparation: Benzoic acid → Benzoyl chloride

  Reaction with phosphorus(V) chloride replaces the carboxyl OH group with chlorine, retaining the acyl carbon and aromatic ring. The new acyl chloride is more susceptible to nucleophilic substitution, while POCl3 and HCl account for the remaining atoms.

• Amide formation: Benzoyl chloride → Benzamide

  Ammonia adds to the acyl carbonyl to form a tetrahedral intermediate. Carbonyl re-formation expels chloride, and proton transfer gives benzamide; additional ammonia captures the acid as ammonium chloride.

• Esterification: Benzoic acid → Ethyl benzoate

  Acid activation allows ethanol to add to benzoic acid; proton transfers and water loss produce ethyl benzoate. The aromatic ring stays intact throughout the acyl substitution.

References

1. Organic Chemistry: Chemistry of Acid HalidesJohn McMurry · OpenStax Organic Chemistry · 2023

   Supports acid-halide preparation with thionyl chloride and nucleophilic acyl substitution chemistry, including tetrahedral intermediates, hydrolysis, alcoholysis and amine acylation at acid chlorides.