14- Acid anhydride reactions

covers: water, alcohol, ammonia, primary amines

What is the functional group change when an acid anhydride reacts with water?

Acid anhydride → carboxylic acid.

What reagent is used for acid anhydride + water?

Water.

What are the conditions for acid anhydride + water?

Room temperature.

What are the products for acid anhydride + water?

Two molecules of carboxylic acid.

Write the general equation for acid anhydride + water.

(RCO)₂O + H₂O → 2RCO₂H.

What is the key difference between the products of acyl chloride and acid anhydride hydrolysis?

Acyl chloride produces carboxylic acid + HCl, whereas acid anhydride produces two carboxylic acid molecules.

What is the functional group change when an acid anhydride reacts with an alcohol?

Acid anhydride → ester.

What reagent is used for acid anhydride + alcohol?

An alcohol.

What are the conditions for acid anhydride + alcohol?

Room temperature.

What are the products of acid anhydride + alcohol?

Ester + carboxylic acid.

Write the general equation acid for anhydride + alcohol.

(RCO)₂O + R′OH → RCOOR′ + RCOOH.

What is the key difference between an acyl chloride and acid anhydride reacting with an alcohol?

Acyl chloride produces ester + HCl, whereas acid anhydride produces ester + carboxylic acid.

What mechanism occurs in acid anhydride + alcohol?

Nucleophilic addition–elimination.

What is the functional group change when an acid anhydride reacts with ammonia?

Acid anhydride → primary amide.

What reagent is used for acid anhydride + ammonia?

Ammonia.

What are the conditions for acid anhydride + ammonia?

Room temperature.

What are the products for acid anhydride + ammonia?

Primary amide + ammonium carboxylate.

What mechanism occurs for acid anhydride + ammonia?

Nucleophilic addition–elimination.

What happens when an acid anhydride reacts with a primary amine?

A secondary amide and an alkylammonium carboxylate are formed.

What are the conditions for acid anhydride + primary amine reactions?

Primary amine at room temperature.

What functional group is formed in acid anhydride + primary amine?

A secondary amide.

What is the general equation for an acid anhydride + primary amine?

(RCO)₂O + 2R′NH₂ → RCONHR′ + R′NH₃⁺RCO₂⁻.

What mechanism occurs during acid anhydride + primary amine?

Nucleophilic addition–elimination.

What is the nucleophile in the reaction of acid anhydride + primary amine?

The nitrogen atom of the primary amine, using its lone pair.

Why are two moles of primary amine used?

One mole forms the amide and the second neutralises the acid by-product.

What product forms from ethanoyl chloride + methylamine?

N-methylethanamide.

What is formed alongside N-methylethanamide from ethanoyl chloride?

Methylammonium chloride.

What is formed alongside N-methylethanamide from ethanoic anhydride?

Methylammonium ethanoate.