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Let us look at the basic reaction of an alcohol with a strong oxidising agent. The oxidising agent can be shown as [O]. The square brackets mean that oxygen is not present as an atom but is supplied during the reaction. Two hydrogen atoms are lost from the alcohol molecule, forming a
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Let us look at the basic reaction of an alcohol with a strong oxidising agent.
The square brackets mean that oxygen is not present as an atom but is supplied during the reaction.
Two hydrogen atoms are lost from the alcohol molecule, forming a carbonyl group, C=O.
The organic product can be an aldehyde or a ketone, depending on whether a primary or a secondary alcohol has been oxidised.
What happens when it is oxidised by acidified potassium dichromate(VI)?
During the reaction, the orange potassium dichromate(VI) solution changes to a green solution that contains chromium(III) ions.
An aldehyde is formed when a primary alcohol is oxidised. Here, propanal is formed from propan-1-ol.
If the primary alcohol is oxidised using distillation apparatus, the aldehyde distils off and is not oxidised further to a carboxylic acid.
Aldehydes are formed when primary alcohols are oxidised at room temperature or using distillation.
Something different happens when an excess of oxidising agent is used at high temperature.
The primary alcohol is oxidised to form an aldehyde, which is oxidised further to form a carboxylic acid.
If a primary alcohol is oxidised under reflux with excess oxidising agent, the aldehyde formed is oxidised to form a carboxylic acid.
What happens when it is oxidised by acidified potassium dichromate(VI)?
During the reaction, the orange potassium dichromate(VI) solution changes to a green solution that contains chromium(III) ions.
A ketone is formed when a secondary alcohol is oxidised. Here, propanone is formed from propan-2-ol.
Tertiary alcohols, like 2-methylpropan-2-ol, cannot be oxidised by acidified potassium dichromate(VI).
Tertiary alcohols, like 2-methylpropan-2-ol, cannot be oxidised by acidified potassium dichromate(VI).