Esters

Question 1

How are esters made?

Answer 1

Esters are made by 2 methods of esterification.

These are both condensation reactions.

carboxylic acid + alcohol

acid anhydride + alcohol

Question 2

What is the name of the process and the reaction between an alcohol and a carboxylic acid?

Answer 2

Esterification is the process of forming an ester.

The reaction is a condensation reaction between COOH and alcohol.

Question 3

What is the other product of esterification?

Answer 3

Water because it is a condensation reaction

Question 4

What is the reagent and conditions for esterification?

Answer 4

A strong acid catalyst e.g. concentrated H2SO4 or HCl or H3PO4.

Question 5

What is an acid anhydride and how are they made?

During the process of making an anhydride whats the byproduct?

Answer 5

An acid anhydride is what forms when 2 identical carboxylic acids react and join together via an oxygen.

The byproduct is water.

Question 6

During base hydrolysis using a dilute alkali such as NaOH, what are the products?

Answer 6

The products are a sodium carboxylate salt which needs further acidification to turn into a carboxylic acid and an alcohol.

Question 7

What are the 2 types of hydrolysis of an ester?

Answer 7

Acid hydrolysis and base hydrolysis.

Question 8

What is acid hydrolysis of an ester?

Give an example of the reagents and conditions used.

Answer 8

When the ester is split into a carboxylic acid and an alcohol. e.g. H+ from H2SO4, under reflux.

Question 9

What are the reagents and conditions for acid hydrolysis of an ester?

Answer 9

Reflux with a dilute acid like HCl or sulfuric acid (H2SO4).

Question 10

What is base hydrolysis of an ester?

Give an example of the reagents and conditions used.

Answer 10

Base hydrolysis is when an ester is split into a carboxylate salt and an alcohol. E.g. NaOH, under reflux.

Question 11

What are the reagents and conditions for base hydrolysis of an ester?

Answer 11

Reflux with a dilute alkali such as NaOH.

Question 12

What physical property do esters have?

Answer 12

Esters smell sweet and fruity.

Question 13

How are esters named?

Answer 13

Remove the -oic acid suffix from the parent carboxylic acid and replace with -oate.

Then the alkyl chain attacked to the oxygen of the -COO- group is added as the first word in the name.

Question 14

What are the 3 differences between base hydrolysis and acid hydrolysis?

Answer 14

In acid hydrolysis, equilibrium is established and the reaction does not go to completion, whereas in base hydrolysis, the reaction is irreversible and therefore goes to completion.

In acid hydrolysis a dilute acid such as H2SO4 is used whereas in base hydrolysis, a dilute alkali such as NaOH is used. Both are heated under reflux tho.

In acid hydrolysis, a carboxylic acid and alcohol is produced, but in base hydrolysis, a carboxylate salt and alcohol is produced. The carboxylate salt can be further acidified into a carboxylic acid.