3.3.9.3 Hydrolysis of Esters

• An ester is formed by the reaction between a carboxylic acid and an alcohol
• In basic hydrolysis of an ester, the carboxylate ion and the original alcohol are formed.
• What are the reactants in the acidic hydrolysis of an ester?

  Ester and water
• What two conditions are necessary for ester hydrolysis to occur?

  Acidic or basic
• Which molecule acts as a nucleophile in the nucleophilic addition stage of acid-catalyzed hydrolysis?

  Water
• What type of ion is formed in the breakdown stage of base-catalyzed hydrolysis?

  Carboxylate ion
• In the base-catalyzed mechanism, the hydroxide ion acts as a nucleophile
• The base-catalyzed hydrolysis of esters shares the same tetrahedral intermediate as the acid-catalyzed mechanism.
• In basic conditions, the hydrolysis of an ester produces a carboxylate ion and an alcohol
• Order the steps of the acid-catalyzed hydrolysis mechanism:

  1️⃣ Protonation of carbonyl oxygen

  2️⃣ Water attacks carbonyl carbon

  3️⃣ Formation of tetrahedral intermediate

  4️⃣ Breakdown to carboxylic acid and alcohol
• The tetrahedral intermediate in acid-catalyzed hydrolysis breaks down to form a carboxylic acid, alcohol, and the acid catalyst.


  True
• Water acts as a nucleophile in the acid-catalyzed hydrolysis of esters.


  True
• Acid-catalyzed hydrolysis of an ester forms the original carboxylic acid and alcohol.


  True
• The general structure of an ester is R-COO-R', where R and R' represent the hydrocarbon groups
• In esterification, water (H₂O) is eliminated to form the ester linkage, resulting in the structure R-COO-R'
• In acid-catalyzed hydrolysis, the carbonyl oxygen of the ester is protonated by the acid
• In base-catalyzed hydrolysis, the hydroxide ion attacks the carbonyl carbon of the ester.
• How does the base-catalyzed hydrolysis of esters differ from the acid-catalyzed hydrolysis?

  Different reaction mechanisms
• What ion is produced in the base-catalyzed hydrolysis of an ester instead of a carboxylic acid?

  Carboxylate ion
• The general structure of an ester is R-COO-R', where R and R' represent hydrocarbon groups.


  True
• Hydrolysis of esters can occur under acidic or basic conditions.

  True
• In the nucleophilic addition step of acid-catalyzed hydrolysis, water acts as a nucleophile
• The acid catalyst protonates the carbonyl oxygen of the ester, making the carbonyl carbon more electrophilic
• Base-catalyzed hydrolysis of esters uses hydroxide ions (OH⁻) under alkaline conditions.
• Acid hydrolysis produces the original carboxylic acid, while base hydrolysis produces the carboxylate ion.


  True
• What is the chemical reaction called where a compound is broken down using water?

  Hydrolysis
• Under what conditions can ester hydrolysis occur?

  Acidic or basic
• What is the process called when an ester is formed from a carboxylic acid and an alcohol?

  Esterification
• In acidic hydrolysis, an acid catalyst helps break the ester bond.

  True
• Acid-catalyzed hydrolysis regenerates the acid catalyst.

  True
• Base-catalyzed hydrolysis reverses the esterification reaction to form the carboxylate ion and alcohol.


  True
• The tetrahedral intermediate in base-catalyzed hydrolysis includes the hydroxide group and ester groups.

  True
• What is the role of hydroxide ions in the activation stage of the base-catalyzed hydrolysis mechanism?

  Acts as a nucleophile
• What is the chemical process called where a compound is broken down by water?

  Hydrolysis
• What happens during the protonation step in the acid-catalyzed hydrolysis of an ester?

  Carbonyl oxygen is protonated
• What does the acid-catalyzed mechanism efficiently hydrolyze esters into?

  Carboxylic acid and alcohol
• Steps in the acid-catalyzed hydrolysis mechanism

  1️⃣ Protonation of the carbonyl oxygen

  2️⃣ Nucleophilic addition by water

  3️⃣ Formation of a tetrahedral intermediate

  4️⃣ Breakdown to carboxylic acid and alcohol
• In base-catalyzed hydrolysis, the final product is a carboxylate ion and an alcohol.
• Match the application with its description:

  Saponification ↔️ Production of soap

  Biodegradation ↔️ Breakdown of fats and oils in the environment

  Digestion ↔️ Hydrolysis of triglycerides by lipases
• The hydroxide ion attacks the carbonyl carbon in base-catalyzed hydrolysis.

  True