33.3 A2 Level

Acyl chlorides

8 flashcards to master this topic

Definition Flip

List three reagents that can be used to convert a carboxylic acid into an acyl chloride.

Answer Flip

Phosphorus trichloride (PCl₃) with heat, phosphorus pentachloride (PCl₅), or thionyl chloride (SOCl₂). These reagents replace the -OH group of the carboxylic acid with a chlorine atom.

Definition Flip

Write the general equation for the reaction of an acyl chloride with water.

Answer Flip

RCOCl + H₂O → RCOOH + HCl. This hydrolysis reaction produces a carboxylic acid and hydrogen chloride gas.

Definition Flip

What type of organic compound is produced when an acyl chloride reacts with an alcohol?

Answer Flip

An ester is formed. The reaction is: RCOCl + R'OH → RCOOR' + HCl. Hydrogen chloride gas is also produced.

Definition Flip

Write the general equation for the reaction of an acyl chloride with ammonia.

Answer Flip

RCOCl + 2NH₃ → RCONH₂ + NH₄Cl. An amide is formed, along with ammonium chloride.

Key Concept Flip

Describe the addition-elimination mechanism of acyl chloride reactions.

Answer Flip

The nucleophile (

Example: water, alcohol, amine) attacks the carbonyl carbon of the acyl chloride (addition). A tetrahedral intermediate is formed. Then, chloride ion is eliminated, regenerating the carbonyl group and forming a new compound (elimination).
Definition Flip

Outline the reaction of acyl chloride with phenol.

Answer Flip

RCOCl + C₆H₅OH → RCOOC₆H₅ + HCl. An ester is formed, along with hydrogen chloride gas. Phenol is benzene ring with an -OH group.

Key Concept Flip

Explain why acyl chlorides are more readily hydrolysed than alkyl chlorides or halogenoarenes.

Answer Flip

The carbonyl carbon in acyl chlorides is more δ+ due to the electronegativity of both the oxygen and chlorine atoms. This makes it more susceptible to nucleophilic attack by water. Alkyl chlorides and halogenoarenes are less polarised and the C-Cl bond is stronger.

Definition Flip

Write the general equation for the reaction of an acyl chloride with a primary amine.

Answer Flip

RCOCl + 2R'NH₂ → RCONHR' + R'NH₃Cl. An N-substituted amide is formed, along with the amine salt.

Ready to test yourself?

Practice with MCQ questions to check your understanding of Acyl chlorides.

Take Quiz
33.2 Esters 34.1 Primary and secondary amines