Re: Fun with chemistry
..., Thu Jul 19 2007, 01:20AM

shikes!

Kids lucky it didn't get started faster... Or explode...

Re: Fun with chemistry
Sulaiman, Thu Jul 19 2007, 01:55AM

I remember doing this with potassium permanganate and glycerine as a youth

just as with antifreeze it takes a while to start -not that dangerous really.

Re: Fun with chemistry
Simon, Fri Jul 20 2007, 05:34AM

I can't watch the video here but I doubt they were being safe enough.

Permanganate mixtures are so unreliable.

Re: Fun with chemistry
Dave Marshall, Fri Jul 20 2007, 06:04AM

Ask Chris F. about his (and mine, and Grant's) lesson about potassium permanganate and sugar. Word of advice...Don't mix it in a water bottle cap.

Dave

Re: Fun with chemistry
AndrewM, Fri Jul 20 2007, 05:36PM

Also from the annals of personal experience: do not sand a block of permangante/epoxy mixture with a dremel tool.

Yeah, I know, admitting that takes me down a notch.

Re: Fun with chemistry
Shaun, Mon Jul 23 2007, 03:43AM

What do you use a permanganate/epoxy mixture for? And isn't the KMnO4 and Glycerine mix supposed to be good for igniting thermite? From the looks of the video is seems fun enough by itself...

Re: Fun with chemistry
Swany, Thu Jul 26 2007, 08:36PM

Yeah, it ignites thermite, but really, there are better ways to go about it IMHO. The leftovers contaminate the thermite and it is messy. Permagnate stains like none other (exept for nitrophenol diazo derivs, which have yet to come off of my countertop, 3 years later).

It is a fun mix. I just aquired a lot of sodium, so I will be preparing some sodium peroxide which tends to ignite on contact with fuels. Fun fun fun for everyone.

Almost forgot; permagnate and glycerin is fun, but manganese heptoxide is that much better. Permagnic acid anhydride, Mn2O7, the stuff is truely the devil. Prepared by dissolving KMnO4 in concentrated H2SO4, I will post more about it later, but belive you me, it is truely awsome.

Re: Fun with chemistry
Chris, Thu Jul 26 2007, 11:21PM

Mn2O7 is a highly unstable and explosive compound, which is to be made and used very cautiously at one's own risk. It explodes if heated to 55C so don't even think about trying to distill it. You really need to mention such points when apparently suggesting the use of such a compound. Even though this information is available to anyone who looks for it, you can't count on people doing that, and this substance is no joke.

Re: Fun with chemistry
Swany, Fri Jul 27 2007, 06:29AM

Distilling it would be a bad, bad, bad idea indeed. Mn isn't meant to be stable in such oxidation states, what goes up must come down!

Oxygen-containing acids condensation products stability is inversely proportional to the acid strength. That is, HClO4 and HMnO4 (both very scary in their own right, stability issues and first acid constants of about 10^8) condense to form large molecules (Cl2O7, Mn2O7) with serious difficulty. H2SO4 can be condensed to form H2S2O7, phosphoric acid forms loads of condensation products in solutions. But I digress, point being, Mn2O7 in any form is not stable!

Mn2O7 prepared by dissolving permagenate in conc. sulfuric acid is not pure; it is in sulfuric acid solution. It will seperate as oily, green drops, but they are still not pure. Brauer outlines the production of pure Mn2O7, 2 eq. KMnO4 (crystalline, ultra-pure for obvious reasons) and 2 eq. H2SO4. Add KMnO4 over a period of 15 minutes to form a slurry, cover and set aside overnight. Solids will form and the Mn2O7 oil is gently kneeded out of the formed stuff with a mortar and pestle... sounds scary!

The stuff decomposes into MnO2 and O3, if you do not cool the former reaction or add slowly enough, purple fumes will evolve into a volcano of porous brown MnO2 and O3.

Really though, it is a very amusing -if not highly dangerous- novel explosive. Drips on kleenex is a personal favorite...