Manganese Heptoxide: Synthesis and Reactions

[Spaceshotx7]

when it reacts, how is the fire created? How does it create heat with the chemical?

[chemlabchemistry]

Im sorry but it is stupid to make such a large amount of Mn2O7. It is actually explosive and ignites the skin when contacted. I did it as well on my channel but with much smaller amounts. A fellow amateur chemist once got a drop of green oil on his skin and was badly burned. I have also done some stupid things doing home chemistry, you learn from it, but not with things like Mn2O7.

I also tried some experimenting with Mn2O7, like extracting it in CCl4, but this is even oxidised. Small scale!

[atourdeforce]

@chemlabchemistry of coarse it was oxidised it is an organic compound, you should of known the outcome before you started.

[endimion17]

I can not believe how stupid some people can be. You NEVER EVER drop combustibles in manganese heptoxide, especially not in a mixture of the heptoxide and concentrated sulfuric acid. You could've been sprayed with the mixture, and it EATS SKIN and it does it PROMPTLY. It is similar to a warm piranha solution. It eats skin and those wounds stay forever.

A man would think that people doing more complex experiments would know what not to do in this classic experiment. But I was wrong.

[ReactionFactory]

@endimion17

Well somehow, we both survived this experiment, which is apparently not supposed to happen. I sincerely hope you choose to forgive us.

[PersonguydudeWB]

@endimion17

You do realize that a lot of common chemicals, acids and such, that are used in a lab destroy or otherwise dehydrate organic compounds? I am sure the maker of this video was wearing proper safety gear.

[trick58]

Hey guys, I appreciate your enthusiasm - I was doing these sames kinds of experiments at a young age and it helped me catch the science bug.. I do caution you to be a bit more careful. The spattering you see is a real problem and these chemicals can cause permanent damage. You also want to pay a bit more attention to your naming - Mn is a transition metal, so you have to use the Stock or Classical system to name it-using the Greek prefix on the oxygen just mixes it up with nonmetal/nonmetals.

[Caswalle]

this is so weird i can and have bought potassium permanganate buy a local store and i can get battery acid and together they will make that!!!

[ReactionFactory]

@Caswalle

I'm not sure that battery acid is concentrated enough to dehydrate the permanganic acid to manganese heptoxide. No matter, the sulfuric acid you're looking for is sold as drain opener!

[purehate2003]

Potassium permanganate and sulfuric acid react to produce some ozone, which has a high oxidising power and rapidly oxidises the alcohol, causing it to combust. As a similar reaction produces Mn2O7, An approximate equation for the ozone formation.....

6 KMnO4 (aq) + 9 H2SO4 (aq) → 6 MnSO4 (aq) + 3 K2SO4 (aq) + 9 H2O (l) + 5 O3 (g)

[Rannyfash]

2*KMnO4 (s) + H2SO4 (aq) → Mn2O7 (l) + K2SO4 (aq) + H2O

your equation is actually two equations,

2*KMnO4 (s) + H2SO4 (l) --> K2SO4 + 2*HMnO4

the concentrated sulphuric acid dehydrates the permanganic acid

to manganese heptoxide,

2HMnO4 --> Mn2O7 + H2O

captain obvious away!!!

[RenXiS47]

Can you explain something thats bugging me:

oxidizer (Mn2O7) + primary alcohol ---> aldehide + water ; why isnt this the case here? Instead you get: CO2 + water

[ReactionFactory]

@RenXiS47

We're talking about totally different strengths of oxidizer here. In terms of which compounds it can oxidize, to what extent it can oxidize them, the rate it which the oxidation occurs, and the energy released by the oxidation reaction, manganese heptoxide is far more powerful than the oxidizing agents that you're thinking of.

[RenXiS47]

@ReactionFactory Tnx for the explanation :D

[zmod101]

remember adehydes can be further oxidixzed thats what your missing here.

[mewrox99]

Are the browns marks on the paper holes from H2SO4 or bits of MnO2

[ReactionFactory]

@mewrox99

They're not due to a reaction with sulfuric acid. The shock of the first explosion threw a mixture of unreacted and reacted chemicals into the air. This caused the brown marks.

[pyr0ph1L]

Is it adviseable to store this stuff in an air-tight glass container?

[ReactionFactory]

@pyr0ph1L

I can't say that it is impossible to store it safely, but it would be highly inadvisable to attempt it. It has a high vapor pressure and is sensitive to shock which causes detonation. It is a much better plan to synthesize it only immediately before it is to be used. Also, its hazards are great enough that it probably shouldn't be considered to be more than a fun curiosity; trying to use it for anything other than experiments like this one would probably end in failure or worse.

[piranha031091]

@ReactionFactory It is simply impossible to store at ambient temperature as it decomposes slowly into MnO2 and O2. (You could in theory store it under -10°C, but as you said, it is far too hazardous)

Great video by the way! It would also have been fun to see you setting frequent objects on fire by placing them into the manganese heptoxide...

[paopaomanalansan]

What compound is there in the fume that has manganese?

[ReactionFactory]

@paopaomanalansan

OzoneNerd here:

That's a good question. I can't guarantee it, but my understanding of manganese heptoxide leads me to believe that the visible fumes are primarily manganese dioxide. Also likely to be present are oxygen, ozone, carbon dioxide and water vapor. The manganese dioxide, oxygen and ozone come from the decomposition of manganese heptoxide; the carbon dioxide and water come from the oxidation of the alcohol we add.

[paopaomanalansan]

@ReactionFactory ah, Mn2O7 is reduced to MnO2 then? isn't the latter a solid substance sort of brown precipitate? why is it gaseous here?

[ReactionFactory]

@paopaomanalansan

It's not actually a gaseous substance here. Visible gases, with the exceptions of the halogens and a few other unusual substances like nitrogen dioxide, which you can see in one of our other videos, are actually suspensions of solid particles in the air. When the redox reaction occurs, large amounts of manganese dioxide, shock, gases and heat are generated. This is more than enough to shoot the manganese dioxide particles into in the air. You don't want them in your lungs.

[paopaomanalansan]

@ReactionFactory certainly, their toxic... thanks for the info.. hope you post videos about reactions of different functional groups, like aldehydes and alcohols,, i am interested... :-)

[ReactionFactory]

@paopaomanalansan

We plan to make a video of the synthesis of diethyl ether via the dehydration of ethanol with sulfuric acid. We might also be synthesizing some chloroform through the haloform reaction in the future. (We've made iodoform in the past, it was fairy boring and smelled bad.) We've also done the reaction shown in /watch?v=NCpG9eIfThk , which involves the oxidation of ethanol into acetaldehyde. Ours was not as good, so we won't film it. We might try /watch?v=53r3ChVkLDg too.

[arnold02000]

Cool