The mechanism of primary alcohol oxidation by acidified potassium manganate (VII) Primary alcohols are easily oxidized. Potassium manganate (VII) is a strong oxidizing agent as compared to potassium dichromate (VI). For potassium manganate (VII), it is impossible to extract the aldehyde formed. The only product is the carboxylic acid.
The mechanism of primary alcohol by acidified potassium manganate (VII) is as shown below:
The aldehyde is formed as an intermediate, but it is unstable under the reaction conditions and cannot be isolated. There is a colour change that accompanies the reaction - the purple solution of KMnO4 turns colourless and brown precipitate of MnO2 is formed.