catlady101
Harmless
Posts: 3
Registered: 6-3-2019
Member Is Offline
|
|
Not KMnO4 - little bangs - sorted
Greetings all Mad scientists, I hope someone here can help please.
Many years ago I worked as a schhool science technician. My Boss at the time was a very talented chap and he often pottered about building and making
things.
Once, he made something with KMnO4 that I would like to re-create at home as am teaching my son the fun bits of science.
so - I can explain the process but I cannot think what the other ingredients are, that is where I hope this sparks a recollection in someone here as
to what it is that I need, here goes...
the KMnO4 crystals were dissolved in a liquid. I have a faint feeling iron filings may have been added at this stage, but not sure if I am
mis-remembering htis as the end result looked like clumps of iron filings.
the process took place in the fum cupboard, but not sure if that was a necessety or just because the rest of us were taking up all the available bench
space.
the solution was carefully swirled for a while and then left int he fume cupboard overnight with his usual post-it of "Do not dispose" just in case we
tidied it away when he was not looking.
the resulting mixture was then filtered ( no heating, no suction, just a glass funnel and some white filter paper folded into a cone)
the collected solids in the filter paper were left to dry overnight, having been tipped onto some simple school grade blue paper towels ( we preferred
those as they quicly showed if you were mopping up water or some other chemical as they reacted to anything but water)
Then.... he let us each carefully take some of the grain solids and told us to throw them at the floor - where they banged and popped ( a mini
explosion if you will).
My Chemistry knowledge simply is not good enough to extrapolate what chemicals , when mixed with KMnO4 would offer an explosive reaction like that (
emphasis on the MINI explosion).
Does any of this ring a bell?
Can someone here complete the formula for me so that we can do this at home?
I have some rudimentary lab equipment here, beakers, funnels, bunsen, tripod, gauze, heatproof mat, I even have an old buchner funnel and hoze if
needed, glass stirring rods, filter papers, test tubes, boiling tubes, an exiled clamp stand and clamps ( some got a bit rusty and found to be not
worth repairing so the school chucked them, and the technicians then foraged them back out for home use - who knew that 20 years later it would become
trendy to use a clampstand and round bottom flask for coffee making???)
Anywho, I digress, if anyone can help, please let me know, I have told my son storied of some of the things my boss got up to and he is keen to try
out this one.
[Edited on 30-3-2021 by catlady101]
|
|
|
njl
National Hazard
Posts: 609
Registered: 26-11-2019
Location: under the sycamore tree
Member Is Offline
Mood: ambivalent
|
|
I'm almost certain it's ammonium permanganate. Slowly turns steel-gray over time.
"The best involves the reaction of silver permanganate and ammonium chloride in water. Silver chloride precipitates and is removed via filtration. The
aqueous ammonium permanganate solution is concentrated by evaporating the water in vacuum and then cooled to precipitate NH4MnO4 crystals."
Similar prep from the wiki
"Another way is to mix a concentrated solution of ammonium chlorate/perchlorate with another of sodium permanganate. Sodium chlorate/perchlorate will
remain in the solution due to its high solubility, while ammonium permanganate will precipitate due to its low solubility in water. The solution is
filtered and the precipitate is washed thoroughly to remove any chlorate/perchlorate traces."
Closer
"A tested method of producing this compound involves dissolving 20 g KMnO4 in 200ml of boiling water, followed by the addition of 250 g ammonium
nitrate and stirred until it dissolves. The solution is poured off into another beaker to leave any undissolved or decomposed products in the bottom.
Chill the solution to 10 °C to precipitate the NH4MnO4, and remove the solution to collect the reddish-purple crystals. Place the product onto
absorbent paper and leave to dry at room temperature. Excess ammonium nitrate must be used, otherwise any leftover potassium permanganate will also
precipitate.[7]"
Looks about right.
Could also be silver permanganate
[Edited on 3-30-2021 by njl]
Reflux condenser?? I barely know her!
|
|
|
catlady101
Harmless
Posts: 3
Registered: 6-3-2019
Member Is Offline
|
|
Hi Njl,
thank-you for your time and willingness to help us out here,
He may have snuck it in the fridge overnight, but it was back in the fume cupboard when I got back in, as I had to move it to prepare something
(chlorine gas I think, I was always a bit paranoid when making it simply because at the time, I could not smell chlorine, at all).
I was so sure it was Potassium Permanganate, as the solution (at the time I had thought he had dissolved it in iodine) was a purplish brown, and there
were crumbs of potassium permanganate near where he had been working - I loved the colour and noticed it immediately, and disposed of it before
starting what I needed to do.
well, turns out I am a complete plonker, but now off to check the data sheets and make sure I can safely do this at home ( may have to commandeer the
beer fridge).
I will go and look up the reaction you mentioned,the picture you kindly linked to ( I missed it was a link to a picture) is very much the same as the
end product I am looking for, if a little finer, but assuming the image was taken by someone practiced at making it, whereas this was the first ( and
as far as I know) the last time my boss made it so it was a bit less shiny and a bit more clumpy.
I am quite certain about what the end product looked like, simply because one of the other technicians ( disaster walking we used to call her) like
clockwork, knocked over the remainder, and we spent the next 10 minutes on our hands and knees making sure we had recovered it all, not that it was
dangerous in itself, but imagine transporting something dangerous-ish and suddenly there is a bang from under your foot, could have been an issue.
I promise not to start ordering chemicals without checking I can do it safely at home first.
Thank-you again - super helpful - should probably change the title of the post though - but no idea how to do that
:-)
[Edited on 30-3-2021 by catlady101]
Here to learn, please be patient.
|
|
|
Vomaturge
Hazard to Others
Posts: 286
Registered: 21-1-2018
Member Is Offline
Mood: thermodynamic
|
|
Probably unlikely (impossible if it really was KMnO4) but is there any chance that there was actual iodine involved? This story sounds plausible for
nitrogen tri iodide.
Then again, I doubt he had you guys scoop up bits of that and throw it on the floor. It goes off eventually on its own as it dries and if the whole
mass of a few grams went off at once, it could definitely hurt someone.
I also am a little sceptical of ammonium permanganate being ignited by hitting the ground. I want to say MrBungee did a video on it and it was
sensitive to heat, friction, impact, but not *that* sensitive.
I now have a YouTube channel. So far just electronics and basic High Voltage experimentation, but I'll hopefully have some chemistry videos soon. |
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
