Sciencemadness Discussion Board

Oxide Manganese... what to do with?

luXi - 5-12-2005 at 03:58

Hello!

I'm new in this great forum (I'm from Israel...).

I wanted to ask what can I do with Oxide Manganese (I think it's M2O4)?

I know it's a catalyst and it can make a chemical reaction with H2O2 (hydrogen peroxide) that creates heat and steams.

There is something else I can do with this stuff?

thx! :cool:

[Edited on 5-12-2005 by luXi]

Darkblade48 - 5-12-2005 at 05:11

Quote:
Originally posted by luXi
I wanted to ask what can I do with Oxide Manganese (I think it's M2O4)?

I believe it's MnO2 (Manganese (IV) oxide) and not the formula you proposed.

I'm not too sure what you could do with the manganese oxide, perhaps you could conduct a thermite reaction to isolate elemental manganese? Also, welcome to these forums!

[Edited on 5/12/05 by Darkblade48]

luXi - 5-12-2005 at 05:30

hey thanks for the answer... =]

so let me understand you..

you're saying that I can put this stuff with a thermite and it'll give some effect to the whole process?

Nerro - 5-12-2005 at 07:07

Quote:
Originally posted by luXi
hey thanks for the answer... =]

so let me understand you..

you're saying that I can put this stuff with a thermite and it'll give some effect to the whole process?
You've effectively said nothing :D

The substance you talk about is called manganesedioxide (also known as MnO<sub>2</sub>;). It is a waste product from oxidation reactions involving KMnO<sub>4</sub> (potassium permanganate). It can catalyze the decomposition of H<sub>2</sub>O<sub>2</sub> into H<sub>2</sub>O and O<sub>2</sub>.

The proposed thermite reaction is a reaction between MnO<sub>2</sub> and a more reactive metal like Mg or Al.

eg: MnO<sub>2</sub>(s) + 2Mg(s) -> Mn(s) + 2MgO(s)

[Edited on Mon/Dec/2005 by Nerro]

[Edited on Mon/Dec/2005 by Nerro]

12AX7 - 5-12-2005 at 08:17

Quote:
Originally posted by Nerro
eg: MnO<sub>2</sub>(s) + Mg(s) -> Mn(s) + MgO<sub>2</sub>(s)


Ahem... MnO2(s) + 2Mg(s) = Mn(lq) + 2MgO(s).

Technically Mg is liquid or gaseous and MnO2 molten when the reaction begins. If the MgO were molten when complete (a flux would help), you could get a reasonable product such as globules of metal.

Mn is pretty reactive so even MnO2, an oxidizer, doesn't burn faster than say, Fe2O3, which has less oxygen.

Oh, and burn it outside, lest you get Parkinsons-like manganese disease.

Tim

Nerro - 5-12-2005 at 11:53

I know I know, its liquid while its being formed but just leave it to stand for a few minutes and it'll be solid. I dont think I'd start working with the Mn before it solidifies anyway.

[Edited on Mon/Dec/2005 by Nerro]

12AX7 - 5-12-2005 at 13:24

Well, you wouldn't, but I would. No wonder I mentioned it :rolleyes: ;)

praseodym - 5-12-2005 at 23:40

Anyway, I believe MnO2 is also used in dry-cell batteries, such as the alkaline batteries and the zinc-carbon batteries, at least in the past. But I am not so sure about whether it is still used in those batteries today.

Douchermann - 6-12-2005 at 06:52

It is still used in alkaline batteries, thats my only source of this stuff today. It is also used to produce chlorine gas but I suggest you don't do that until you've got the proper safety equipment

MnO2 + 4HCl ---> Cl2 + MnCl2 + 2H2O

One of the cleanest ways to prepare manganese metals (but also fairly dangerous) would be to electrolise MnCl2. It melts at a high temp, but nothing as high as salt or calcium chloride. It melts at about 600-700 Celcius.

Fleaker - 7-12-2005 at 16:25

Doesn't NaCl melt at like 814C or so? 600-700 is at aluminum melting temperatures, a good cherry red heat. However, you could probably make a lower melting eutectic mixture with some other halide and electrolyze it. Works with CaCl2 and NaCl I might add :cool:

reduction or oxidation

chloric1 - 7-12-2005 at 17:44

Manganese Dioxide-
Reacts with Hydrochloric or Hydrobromic acid to release free halogen. What ius novel here is that it works better with slight warming so the gas evolution can be abated by freezing cold (Dry Ice/acetone or Calcium chloride and crushed ice). A strong advantage over hypochlorite methods

Reduced by oxalic acid in the presence of a mineral acid to form carbon dioxide and the Mn+2 salt of the mineral acid used. Boiling is necessary from what I have read.

Heating with barium nitrate at 600 C will produce the manganate. Also will form manganates with strong bases with ample oxygen supply.

Oxidizes sulfur dioxide in aqueous solution to furnish manganous dithionate. This can be converted to the sodium salt or barium salt for further synthesis.

There is more to be done with this valuable oxide but I am too lazy to write more. Download "Handbook of Preparative Inorganic Synthesis" from the forum's library.