doranobi - 17-6-2011 at 07:56
Hi everyone.
As you may know that Mn2O7(prepared by mixing KMnO4 with conc. Sulfuric acid) has the potential to set almost all organic stuff on fire or even lead
to explosion.
But I have read the article that said that in the mixture of KMnO4 and conc.Sulfuric acid MnO3+ is formed.Well I am sure that this ion must be really
really reactive.
So I'd like to ask if it possible that MnO3+ will acts as the electrophile when reacting with toluene(Or may be with benzene)
I got the idea from the mechanism of Nitration that Nitronium ion acts as the electrophile.
Is obvious that if if just mix toluene with Mn2O7 it will surely explode.But what if I do this under the inert atmosphere?
I have tried some experiment. I drop a little drop of Mn2O7 onto the cotton in the open air,it almost explode. But when I burned all O2 in my reaction
vessel the almost nothing happen.But I'm not quite sure about this idea.So I'd love to hear from you here before I could further my experiment(Because
it tends to explode sometimes)
redox - 17-6-2011 at 09:19
Well, I believe MnO3+ ions only form in the extremely concentrated and dehydrating mixtures of sulfuric acid with permanganate. Dripping this mixture
into toluene would only oxidize the toluene to CO2 and H20, I think. I don't see why an inert atmosphere would help at all. Are you sure your Mn2O7 on
cotton in an sans-oxygen atmosphere results were valid?
Also, If the reaction DID proceed as you suggest, there would be a manganese-carbon bond, which I had thought only existed in carbonyl compounds, such
as dimanganese decacarbonyl.
But please, experiment!
doranobi - 17-6-2011 at 23:12
Thank you for your comment Redox.
Here is the video of my experiment that I talked about.As you can see I'm not sure that the result was valid but I can see that Mn2O7 is less reactive
if i burn out the O2. So I think if there's no O2 it may not ignite the cellulose or toluene and if i left it for about half an hour(Just like
Nitration but i will give it more time).That reaction as I suggest above may occur.
So what do you think??
Click to see Video
ItalianChemist - 18-6-2011 at 02:37
toluene explodes in contact with Mn2O7 also in the absence of atmospheric oxygen, as Mn2O7 is an oxidizing agent.