Oxidation of alcohols and aldehydes

Question 1

Write the equation for the oxidation of ethanol to ethanal.

Answer 1

CH₃CH₂OH + [O] ⇒ CH₃CHO + H₂O

Question 2

Write the equation for the oxidation of ethanal to ethanoic acid.

Answer 2

CH₃CHO + [O] ⇒ CH₃COOH

Question 3

Write the equation for the oxidation of ethanol to ethanoic acid.

Answer 3

CH₃CH₂OH + 2[O] ⇒ CH₃COOH + H₂O

Question 4

What can primary alcohols be oxidised to?

What can secondary alcohols be oxidised to?

Answer 4

• Primary alcohols can be oxidised to aldehydes and then can be further oxidised to carboxylic acids.
• Secondary alcohols can oxidised to ketones.

Question 5

What are the conditions needed to prepare aldehydes?

Answer 5

You need to distil the aldehyde from the reaction mixture as it is formed. This prevents the aldehyde being oxidised further to a carboxylic acid.

Question 6

What are the conditions required to prepare a carboxylic acid?

Answer 6

When making the carboxylic acid, the reaction mixture is usually heated under reflux before distilling the product off.