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reactivity of KMnO4 (potassium permagantate)

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ramses

Thu Mar 13 2008, 07:53PM

Registered Member #1208 Joined: Thu Jan 03 2008, 05:30PM
Location: Chesterland, OH
Posts: 154

yes glycerin suppositories are what i had planned to use, and no offense, but the implied purpose of the thread was to gather information about fuels to use in the rocked fuel, so that it won't randomly blow up/catch fire/make poison/some other bad thing. thanks for the info about the electrical ignition, but it seems to be unpredictable based on how much the steel wool is twisted, how good the contact is, etc. extensive fuse testing will be done before it is used to ignite an actual fuel.

edit: not steel wool, thin wire. silly me! but still hard to get working. i think the light and run method is much cooler anyway.

ramses

johnf

Tue Apr 01 2008, 08:40AM

Registered Member #230 Joined: Tue Feb 21 2006, 08:01PM
Location: Gracefield lower Hutt
Posts: 284

I used to make things that reacted very very quickly that used the permanganate plus glycerine fuse then permanganate and aluminium powder (fast heat source) then anhydrous ammonium nitrate and aluminium powder as the final burn very very fast fuel.
A pound of the final is equivalent to many tens of pounds of TNT

be very very careful !!!
also note the fuse is tempermental if it doesnt go off, leave it for days before working out a way to soak it with water!!!

I would think that the permangante /aluminium power plus amoderator such as aluminium oxide would make a controllable rocket fuel the al oxide to slow rate to desired burn.

Bored Chemist

Tue Apr 01 2008, 04:56PM

Registered Member #193 Joined: Fri Feb 17 2006, 07:04AM
Location: sheffield
Posts: 1022

"A pound of the final is equivalent to many tens of pounds of TNT"
In what sense?
BTW, I don't think ammonium nitrate forms a hydrate under normal conditions.

ramses

Tue Apr 01 2008, 07:51PM

Registered Member #1208 Joined: Thu Jan 03 2008, 05:30PM
Location: Chesterland, OH
Posts: 154

Johnf- by energy output, maybe, although I doubt it. by detonation velocity, your out of your mind! point being that there is no comparison. i'm not sure Al2O3 would be good to mix with a sensitive fuel, since it is an abrasive. perhaps charcoal powder would do better, since it actually contributes to the reaction and produces lots of exhaust gas.

Bored Chemist- I hate to contradict you, but ammonium nitrate is very soluble in water

from wikipedia:
"The highly water-soluble salt..."

sorry if I am wrong, but i believe that it is hygroscopic. given KMnO4's dislike of water(spontaneous ignition and purple-ness), it doesn't seem like a good idea to be mixing water absorbent material.

ramses

Bored Chemist

Tue Apr 01 2008, 08:44PM

Registered Member #193 Joined: Fri Feb 17 2006, 07:04AM
Location: sheffield
Posts: 1022

Ammonium nitrate is very soluble in water. So is sodium sulphate.
If you cool a solution of sodium sulphate it crystalises out as a hydrate- the decahydrate as it happens- Na2SO4. 10 H2O
Ammonium nitrate crystalises out as the anhydrous material NH4NO3.
So far as I'm aware it doesn't form a hydrate. Weird conditions of temperature and pressure might make it do so, but I don't think they are what's being talked about here.

There's a difference between anhydrous and dry.

johnf

Wed Apr 02 2008, 09:10AM

Registered Member #230 Joined: Tue Feb 21 2006, 08:01PM
Location: Gracefield lower Hutt
Posts: 284

Yes the al2o3 may be very hard /abraive but i mentioned it as it not likely to react in the mentioned reaction as the bond strength is considerable there are other compounds that are as good and maybe softer

The ammonium nitrate plus Al powder is known as ammonal and is a compression explosive ie it needs a massive jar to set off ie detonator or such like
commonly used in mines (minefields) and quarrying (making montainsides collapse into gravel)

check out the link 450 tons ammonium nitrate plus other ingredients =1-2 kilotons of tnt

ramses

Wed Apr 02 2008, 07:41PM

Registered Member #1208 Joined: Thu Jan 03 2008, 05:30PM
Location: Chesterland, OH
Posts: 154

even so, I don't want to make a pound of somthing that is as powerful as many 10's of pounds of TNT.

I want to make a rocket motor, not a massive pipe bomb.

additionally, have you compared the results of your mixture with actual TNT under the same conditions? That was a rhetorical question, since "...illegal explosives are not an acceptable topic of discussion."

If it is not illegal to make bombs and use dynamite in your are, I envy you, apologize for any flaming, want to live where you live etc.

again, not trying to flame, but the past 5 or so posts are quite off-topic. If I decide to move to the desert, however, they may be invaluable to my entertainment...

ramses

ps. 101th post!

Billybobjoe

Thu Apr 03 2008, 01:58AM

Registered Member #396 Joined: Wed Apr 19 2006, 12:55AM
Location: Pittsburgh, PA
Posts: 176

I hate to suggest KNO3 but KMnO4 does not seem like the most reliable or safe chemical to use in any pyrotechnic composition - Skylighter.com doesn't even sell it, and on the massive database of pyrotechnic formulas and compositions available from them, it is only listed on some non recommended very sensitive flash powder mixtures. It is useful for fuses with glycerin like you mentioned though (among other chemistry related uses).

You can get KNO3 for very cheap on eBay - I have 20 lbs. - don't remember what I paid but it was probably not more than $2/lb. But if you insist on KMnO4, I'm interested where you're getting it from at such a better price and in more readily available quantities than KNO3 (that may sound sarcastic but its not meant to - I'd actually like to know).

ramses

Fri Apr 04 2008, 08:07PM

Registered Member #1208 Joined: Thu Jan 03 2008, 05:30PM
Location: Chesterland, OH
Posts: 154

tractor supply has 5 lbs for USD 22 + 6.5% tax which comes out to ~$26 for 5 lbs, around $5.20 per pound.
I mainly wanted to do this locally, so I wouldn't have to mess around with shipping. KNO3, or what I suspect is, costs ~$7 per pound + tax,and is probably much less powerful.

If we assume K2O is given off, than 2 moles KNO3 give off 5 moles Oxygen, while if K2O and Mn2O are given off we get 6 Moles of Oxygen. plus, a more potent oxidizer would let me use less exotic fuels, and the extra O2 would let me use less of the oxidizer, the most expensive part to buy.

I will check Ebay, just in case someone decides to sell it ~$2.00 per pound. I need a scale anyway!

EDIT: I just checked and they do have it at ~$2.00 per pound including shipping, but I really don't have a use for 20 lbs of KNO3

ramses

Bored Chemist

Sat Apr 05 2008, 01:43PM

Registered Member #193 Joined: Fri Feb 17 2006, 07:04AM
Location: sheffield
Posts: 1022

You need to compare the molecular weights too.

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