Question

Synthesis of a Chemiluminescence Compound: Luminol

Why does luminescence stop if the container of luminol, DMSO and KOH is kept closed or in other words, why is oxygen necessary for the reaction?

Answer 1

Luminol is oxidized (with molecular oxygen) in the presence of sodium hydroxide. When the students

shake the tube, they are introducing oxygen into the solution.

That’s why the reaction doesn’t work unless they shake the tube and why chemiluminescence stops when they set the tube aside.

The higher the reaction temperature, the faster the reaction, the more intense the chemiluminescence.

On closing or stoping the oxygen supply oxidation also stops so chemiluminescence stops