After mixing two liquids, at first, a weak red glow appears, and then the solution foams and emits a blue glow.
name: Hydrogen peroxide reacts with pyrogallol, formaldehyde and luminol.
Two Colour Chemiluminescent Clock Reaction - Periodic Table of Videos
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Trautz-Schorigin Reaction / Two colour chemiluminescence [HD]
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Wear eye protection and lab gloves. This experiment should be performed in a fume hood.
Avoid contact of hydrogen peroxide, sodium hydroxide and pyrogallol with skin. Pyrogallol can be absorbed through the skin.
Avoid inhaling the formaldehyde vapours
Always follow general safety
recommendations. Please note that conducting chemistry
experiments you must comply with the relevant legal procedures in
2CH2O + 3H2O2 → CH2(OH)OO(OH)CH2 + 1O2 +2H2O
C8H7N3O2 + 2OH- + O2 → C8H5NO42- + 2 H2O + N2
- Mix 40 ml of water and 0.8 g of sodium hydroxide in a 250-ml beaker.
- Add 5 mg of luminol, 25 g of potassium carbonate and 1 g of pyrogallol into the beaker. Stir to dissolve.
- Add 10 ml of about 40% formaldehyde.
- Pour the resulting solution into a 1-l beaker.
- Add 30 ml of 30% hydrogen peroxide into the mixture. It is better to do this in a dark room.
There are two oxidation reactions in this experiment. The first reaction is known as Trautz-Schorigin reaction. It is the oxidation of formaldehyde by alkaline hydrogen peroxide in the presence of pyrogallol. Singlet molecular oxygen is produced in this reaction, and it converts to triplet oxygen with a weak emission of red light. This reaction is strongly exothermic, and the solution temperature may increase to 90 °C.
The second reaction is the oxidation of luminol, in which blue glow is emitted.
Full detailed reactions are very complicated, and there are only simplified reactions in this description.