Oxidation of alcohols
The partial oxidation of an alcohol can be brought about by using an oxidising agent.
Some typical oxidising agents are:
- acidified potassium dichromate solution
- acidified potassium permanganate solution
- hot copper (II) oxide (black solid)
- Benedict’s reagent
- Tollen’s reagent (silver-mirror)
Watch this video for a demonstration of oxidising alcohols using acidified potassium dichromate solution
Primary alcohols
Oxidation of primary alcohols forms two products in a two stage reaction.
When carbon compounds are oxidised, the oxygen to hydrogen ratio increases, so either oxygen atoms are being added to the compound, or hydrogen atoms removed.
The first stage oxidation of a primary alcohol involves the molecule losing two hydrogen atoms to form an aldehyde.
Consider the oxidation of propan-1-ol.
Stage one
Stage two
In the second stage, oxygen is added to the aldehyde molecule to form a carboxylic acid.
Secondary alcohols
Unlike primary alcohols, secondary alcohols can only be oxidised once.
Watch this video for a demonstration of investigating whether aldehydes and ketones can be oxidised.