Alkaline potassium permanganate (KMnO4) solution is called as bayer's reagent. It is prepared by dissolving anhydrous sodium carbonate (Na2CO3) in a KMnO4 solution. Baeyer's reagent can oxidize alkenes and alkynes.
It is used as a potent oxidizing agent and used in the qualitative organic analysis to test for the presence of unsaturated alkenes and alkyne groups. Baeyer's reagent interacts with alkene and alkyne, changing its pinkish-purple colour to brown colour (due to formation of manganese dioxide).
There are some conditions to be careful when baeyer's reagent is prepared for alkene oxidation to diol.
Alkene compounds can be oxidized to diol and alkyne compounds can be oxidized to vicinal diketones or dialdehyde (Vic-diketones or 1,2-diketones) or, under more vigorous conditions, carboxylic acids.
Two -OH groups are attached to the carbon atoms in alkene group as in the figure.
Alkyne compounds can be oxidized to vicinal diketones or dialdehyde (Vic-diketones or 1,2-diketones) or, under more vigorous conditions, carboxylic acids by baeyer's reagent. More vigorous conditions can be made by increasing the alkalinity of the solution by adding potassium hydroxide (KOH). KOH is a strong alkali.