Potassium permanganate

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Legality: DEA Listed Chemicals

Production of this substance may be illegal in some jurisdictions under certain circumstances.

21CFR1310.02 a & b

In 1995/6, two lists were created "List I" and "List II", for which commercial manufacturers and distributors must register, and for which possession with the intent to manufacture illegal substances (such as methamphetamine, ecstasy, etc) is illegal. On these a few dozen "precursor" compounds commonly used in the manufacture of illegal drugs. [1] [2]

Bottom line: Do not produce this chemical without checking to make sure that you may do so legally.

 
 
Potassium permanganate
DEA LIST I/II SUBSTANCE
Chemical formula KMnO4
OTP appearance purple solid 
Molar Mass(g/mol) 158 
Density(g/cc) 2.703 
Index of refraction 1.59 
Solubility in water(g/L) 63.8
NFPA 704
NFPA704.png
0
2
0
OX

 

Thermal Decomposition
Potassium permanganate
240°C
K2MnO4,MnO2,O2

Potassium permanganate is a widely used strong oxidizer, somewhat similar to sulfuric acid in its ubiquity. It could be argued that it should listed among the industrial chemicals, since three tons are produced for every 400 of hydrochloric acid.

Uses

Primary

  • Pharm: WHO LEM medicine
  • Source of gaseous oxygen
  • Water treatement (oxidizes and removes iron, manganese, hydrogen sulfide, and other materials)
  • Produces fire when mixed with glycerol
  • Used in analytic chemistry
  • Pharmacopia: treats dermatitis and dermal fungal infections
  • Pharmacopia: disinfectant

Hazards

  • Skin and mucal membrane irritant, particularly in powder form
  • As a strong oxidizer, this substance can form explosive compounds
  • As a strong oxidizer, this substance can ignite organic compounds
  • Potassium permanganate can stain many natural fibers and substances purple

Natural Occurrence

Character

Oxidation mechanism

Potassium permanganate donates oxygen by divesting itself of a molecule of manganese dioxide and two oxygens:

2 KMnO4 K2MnO4 + MnO2 + 2 O

Production

Synthesis

The short version is that the -permanganate is produced by oxidizing potassium manganate.

Chemical

Chlorine gas

Bubble chlorine gas through a concentrated solution of potassium manganate. Or possibly directly over the solid?

2 K2MnO4(aq) + Cl2(g) 2 KMnO4(aq) + 2 KCl(aq)
Hydrochloric acid

An easier, but lower yield method: combine hydrochloric acid with potassium manganate

3 K2MnO4(aq) + 4 HCl(aq) 2 KMnO4(aq) + MnO2(s) + 2 H2O(l) + 4 KCl(aq)
Carbon dioxide

Bubble carbon dioxide through a potassium manganate solution. Like the hydrochloric acid method above, this decomposes some of the manganate, lowering the yield.

3 K2MnO4(aq) + 2 CO2(g) 2 KMnO4 + 2 K2CO3 + MnO2

Electrolytic

Noble electrodes
  1. Gather 60-220 units by mass of potassium manganate
  2. Gather 150 units by mass of potassium hydroxide
  3. Gather 1000 units by mass of water
  4. Prepare two electrodes of nickel or stainless steel. The anode should have 10 times as much surface area as the cathode
  5. Mix the materials above thoroughly
  6. Heat the solution to 40-60°C
  7. Place the electrodes into the solution, not allowing them to touch
  8. Apply 2.3-3v at 50 A/m2
  9. Agitate or stir (if possible) during electrolysis
Reactive electodes
  1. Prepare a cathode of porous copper oxide
  2. Prepare an anode of manganese
  3. Submerge the electrodes in a solution of molten potassium hydroxide
  4. Apply current
    7 CuO + 2 Mn + 2 KOH
    {
    ≥406°C}
    7 Cu + 2 KMnO4 + H2O

Purification

Testing

Storage

Disposal

See Also

References

  1. "Emphasizing the "Control" in controlled substances"
    United States Drug Enforcement Agency
    link last accessed 11 September 2012.
  2. "Controlled Substances Act; Title 21; Chapter 13; Subchapter I"
    United States Food & Drug Administration
    link last accessed 11 September 2012.