Potassium permanganate solution fades because the main component of cinnamon oil is unsaturated fatty acids with double bonds.

High-concentration potassium permanganate does not add acid (not acidic potassium permanganate), so potassium permanganate reacts with hydrogen peroxide to form manganese dioxide, which continues to oxidize hydrogen peroxide, manganese From 4 to 2, but no acid is added to potassium permanganate, so white Mn(OH)2 is generated.

2KMnO4 3 H2O2 ===2 MnO2 3 O2 2 KOH 2 H2O

MnO2 H2O2 ===Mn(OH)2 O2 (under KOH environment)

Continue the reaction for half an hour, bubbles are still generated, but precipitates begin to sink, and are pushed to the surface of the liquid in the test tube by the bubbles. The precipitates begin to circulate and form clumps (MnO2 can catalyze the decomposition of H2O2, so the number of bubbles is accelerated, The precipitate is pushed to the surface of the liquid in the test tube by the bubbles).

Extended information:

As an oxidizing agent, potassium permanganate is greatly affected by pH and has the strongest oxidizing ability in acidic solutions. Its corresponding acid permanganate HMnO4 and acid anhydride Mn2O7 are strong oxidants, which can automatically decompose and generate heat, and cause combustion when in contact with organic matter.

Potassium permanganate has strong oxidizing properties and is commonly used as an oxidant in laboratories and industries. It decomposes when exposed to ethanol. It will slowly decompose into manganese dioxide, potassium salt and oxygen in acidic media. Light catalyzes this decomposition, so it is often stored in brown bottles in laboratories. It can be seen from the element potential diagram and the free energy oxidation state diagram that it has extremely strong oxidizing properties. In alkaline solutions, its oxidizing properties are not as strong as in acids. When used as an oxidant, the reduction products vary depending on the acidity and alkalinity of the medium.

Baidu Encyclopedia-Potassium permanganate