Oxidation of Aldehydes

Question 1

What is the carbonyl group?

Answer 1

C=O

Question 2

Difference between an aldehyde and a ketone structurally?

Answer 2

In aldehydes : Carbonyl group always bonded to 1 H atom. (at end of chain)

In ketones : Carbonyl group always bonded to 2 alkyl groups (middle of chain)

Question 3

How should the apparatus for oxidation of a primary alcohol to an aldehyde be set up?

Answer 3

• Aldehyde should be distilled off as it is produced
• To prevent further oxidation into a carboxylic acid

Question 4

How would we oxidise a primary alcohol straight to a carboxylic acid?

Answer 4

Heat the reaction mixture under reflux

Aldehyde would be produced but drop back into reaction mixture until reaction mixture contains all carboxylic acid.

Question 5

What is the oxidising agent used for all oxidation reactions?

Answer 5

Potassium dichromate and sulphuric acid.

K2Cr2O7 + H2SO4

Question 6

What happens when ketones are FURTHER oxidised and why?

Answer 6

• They aren’t
• No available H atom
• Really strong [O] needed, and would probably break a C-C bond