3.3.9.5 Acid Anhydrides

• Acid anhydrides are formed from two carboxylic acid molecules when they combine and lose a molecule of water
• The naming convention for acid anhydrides involves replacing "acid" in the carboxylic acid name with anhydride
• Carboxylic acids are formed by the oxidation of primary alcohols or aldehydes
• Acid anhydrides are more reactive than carboxylic acids due to the presence of two acyl groups


  True
• The general formula for acid anhydrides is (RCO)₂O

  True
• Carboxylic acids have the general formula (RCO)₂O

  False
• Acid anhydrides are formed when two carboxylic acid molecules combine and lose a molecule of water
• Steps in the hydrolysis of acid anhydrides

  1️⃣ React with water

  2️⃣ Break oxygen-carbon bond

  3️⃣ Form two carboxylic acids
• Acid anhydrides undergo hydrolysis to form two molecules of carboxylic acid
• What is the general formula for acid anhydrides?

  (RCO)₂O
• Reactions of acid anhydrides in order of their reaction types.

  1️⃣ Hydrolysis

  2️⃣ Alcoholysis

  3️⃣ Ammonolysis

  4️⃣ Reaction with Amines
• Ammonolysis of acid anhydrides forms an amide and a carboxylic acid.


  True
• What types of groups can the R group in an acid anhydride represent?

  Alkyl or aryl
• Acid anhydrides are more reactive than carboxylic acids because they have two acyl groups linked by an oxygen atom.

  True
• Carboxylic acids are formed by dehydration of two acid anhydrides.

  False
• What are the products of the hydrolysis of acid anhydrides?

  Two carboxylic acid molecules
• What products are formed from the hydrolysis of acid anhydrides?

  Two carboxylic acid molecules
• What are the products of the reaction between an acid anhydride and ammonia?

  Amide and carboxylic acid
• The increased reactivity of acid anhydrides compared to carboxylic acids makes them useful in organic synthesis
• What happens during the formation of acid anhydrides?

  Dehydration
• What distinguishes acid anhydrides from carboxylic acids in terms of structure?

  Two acyl groups
• Which compound is more reactive: acid anhydrides or carboxylic acids?

  Acid anhydrides
• What structural feature makes acid anhydrides more reactive compared to carboxylic acids?

  Two acyl groups
• Acid anhydrides undergo hydrolysis to form two carboxylic acid molecules


  True
• Match the reaction of acid anhydrides with its key change:

  Hydrolysis ↔️ Forms two carboxylic acids

  Alcoholysis ↔️ Forms ester and carboxylic acid

  Ammonolysis ↔️ Forms amide and carboxylic acid
• Acid anhydrides are more reactive than carboxylic acids.


  True
• What are the products of the alcoholysis of acid anhydrides?

  Ester and carboxylic acid
• Acid anhydrides are formed from two carboxylic acids by losing a molecule of water
• Acid anhydrides are formed when two carboxylic acid molecules lose a molecule of water
• Acid anhydrides are more reactive than carboxylic acids because they have two acyl
• Acid anhydrides are more susceptible to nucleophilic attack than carboxylic acids.


  True
• Arrange the reactions of acid anhydrides based on their reactivity from most to least reactive.

  1️⃣ Reaction with Amines

  2️⃣ Ammonolysis

  3️⃣ Alcoholysis

  4️⃣ Hydrolysis
• Acid anhydrides react with alcohols to form an ester and a carboxylic
• What are the products of the reaction between an acid anhydride and an alcohol?

  Ester and carboxylic acid
• What are the products of the hydrolysis of acid anhydrides?

  Two carboxylic acids
• What type of reaction occurs when an acid anhydride reacts with water?

  Hydrolysis
• Acid anhydrides react with amines to form a substituted amide and a carboxylic
• Hydrolysis of acid anhydrides results in two molecules of a carboxylic
• What is the general formula for acid anhydrides?

  (RCO)₂O
• Match the formation method with the resulting formula:

  Dehydration of carboxylic acids ↔️ (RCO)₂O

  Oxidation of alcohols ↔️ RCOOH