How to get KMnO4 from MnO2?

letmeregister · Post by **letmeregister** » Thu Nov 20, 2014 3:19 pm

MnO₂ --X--> KMnO₄
Can anyone help me with the equation, please?

I've been trying to solve it for a half of an hour already and I have a test tomorrow...

Rodrigo Pires · Post by **Rodrigo Pires** » Wed Nov 26, 2014 4:23 am

Preparation
Potassium permanganate is produced industrially from manganese dioxide, which also occurs as the mineral pyrolusite. The MnO₂ is fused with potassium hydroxide and heated in air or with another source of oxygen, like potassium nitrate or potassium chlorate. This process gives potassium manganate:

2 MnO₂ + 4 KOH + O₂ â†’ 2 K₂MnO₄ + 2 H₂O

The potassium manganate is then be converted into permanganate by electrolytic oxidation in alkaline media:

K₂MnO₄ + H₂O â†’ KMnO₄ + KOH + 1/2 H₂

Other methods
Although of no commercial importance, potassium manganate can be oxidized by chlorine or by disproportionation under acid conditions. The chlorine oxidation reaction is:

2 K₂MnO₄ + Cl₂ â†’ 2 KMnO₄ + 2 KCl

And the acid-induced disproportionation reaction may be written:
3 K₂MnO₄ + 4 HCl â†’ 2 KMnO₄ + MnO₂ + 2 H₂O + 4 KCl

A weak acid acid such as carbonic acid is sufficient for this reaction:
3 K₂MnO₄ + 2 CO₂ â†’ 2 KMnO₄ + 2 K₂CO₃ + MnO₂

Potassium permanganate crystallizes from the concentrated reaction solution.

From: http://en.wikipedia.org/wiki/Potassium_permanganate

letmeregister · Post by **letmeregister** » Thu Dec 04, 2014 1:35 pm

Thank you very much for your help. However, my textbook tells me to make it all in one step. Would that be possible?