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Author: Subject: Hypochlorites and Permanganates
Farnsworth
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[*] posted on 2-8-2012 at 21:16
Hypochlorites and Permanganates


I have some basic chemistry education, but my bread and butter in college were math and physics. I've been doing a little fiddling in my head lately, and I'd like to ask a couple questions concerning these...rather potent materials.

There doesn't seem to be a lot of material out there concerning energetics using these compounds beyond a piece or two of Dumbasses' Cookbook type examples. What I do know is that both compounds are extremely reactive, often to the point of unpredictable self-initiation, when combined with a wide variety of fuels.

Hypochlorites interest me because they are one of the few compounds in the chlorate/chlorite family that is still widely available OTC. Ditto for permanganates. In the latter case I'm given to understand that KMNO4 is suitable as a component in certain sprengel type explosives or cheddites if combined with a narrow list of suitable complements. This avoids critical oversensitivity.

First question is, is this correct?

The second is a follow on to the first. Are there any known hypochlorite combinations that do NOT express the unruly hypersensitivity that normally precludes their use in energetics?

It just seems a pity that these two components are there, relatively unrestricted, but totally unusable due to their sensitivity.


--Farnsworth
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CaliusOptimus
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[*] posted on 2-8-2012 at 23:13


As far as fast burning mixtures are concerned (ie flash powder) these ingredients are truly out of the question. I'm sure there are probably a few slower comps that can be made and handled with safety, but in general these two are of exiled from the list of safe and useful pyrotechnic oxidizers.

Consider mixing them with some less reactive fuels on a ~1g scale to test the sensitivity. Personally, I've always been curious to know how they would behave in a fine mixture with polyethylene, PVC or parlon.

[Edited on 3-8-2012 by CaliusOptimus]
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hyfalcon
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[*] posted on 3-8-2012 at 02:16


Why waste the chlorine donor? Unless he's making colored stars that is. Try some red gum.
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Kalium
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[*] posted on 3-8-2012 at 02:35


I can give you some insight on using KMnO4 in pyrotechnic compositions.
When I was 16 and just wanted to make loud noises (I wasn't interested very interested in chemistry then) I used KMnO4 as an oxidiser for flash powder in the span of over a year. I mixed it with 400 mesh atomised aluminium in a ratio of 4:1. The mixture was very insensitive and wouldn't even ignite from a blue flame. As a test I stored a sample of 10g in a plastic container for half a year and there was no apparent decomposition. It had decent power when highly confined and it produced a large amount of greenish, pungent smoke. I was the ultimate 'kewl' but still, my findings showed that when mixed with a relatively unreactive fuel and kept away from humidity, KMnO4 can be used quite safely.
Unfortunately I can't help you with hypochlorite mixtures; this site has taught me to steer clear of them.
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[*] posted on 3-8-2012 at 08:27


I read a story of a fellow in the lab grinding a fair amount of KMNO4 and aluminum powder in a mortar and pestle. It blew a hole through the desk, ripped the skin off his face and arms, along with some fingers lost. He had to get multiple skin grafts.

One time I ground about a teaspoon of purple salt in a mortar and pestle and then wearing a face shield, ear protection, and heavy gloves added some aluminum powder. I very gently ground the two together using a tiny brush to get the fine mixture off the sides of the wall of the mortar from time to time as I went along. In increments I made about 2 tablespoons and set this pile on the ground and placed one very small drop of glycerine on the pile, with a small depression on top to keep the glycerine from rolling off the talc-like mix.
In a few seconds a wisp of smoke formed from the glycerine reacting with the permanganate. Then nothing, and I waited and waited for about 15 seconds. Never had it taken so long to light. It seemed like a half minute went by and then there was this thunderous detonation, rattling the windows of my house.
Other times I would fill a plastic bottle cap with about a teaspoon of the mix and set it off with glycerine. This would create a really nice smoke ring effect with the detonation, the torus climbing high above the blast.
The moral of the story is never grind more than you want to blow up in your face. In fact, even gently grinding KMNO4 and Al powder in any amount is pretty stupid. I shattered a small mortar and pestle with way less than a half teaspoon of this mix, just tapping the pestle against the walls to get the fine powder to unstick/shake free from the sides of the mortar. I recall the explosion was very loud and was lucky to have not injured my eyes.
It's funny how poorly granular KMNO4 burns with powdered aluminum and then as you grind it more it produces a muffled dull thud or poof of a sound when lit, hinting at what it can do when finely mixed.

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[*] posted on 3-8-2012 at 14:46


As for me, the best way to use hypochlorites is to convert them to chlorates. Better oxigen balance and so on. It is very simple procedure.



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Farnsworth
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[*] posted on 3-8-2012 at 20:01


Quote:
As far as fast burning mixtures are concerned (ie flash powder) these ingredients are truly out of the question. I'm sure there are probably a few slower comps that can be made and handled with safety, but in general these two are of exiled from the list of safe and useful pyrotechnic oxidizers.

Consider mixing them with some less reactive fuels on a ~1g scale to test the sensitivity. Personally, I've always been curious to know how they would behave in a fine mixture with polyethylene, PVC or parlon.


This is sort of what I had in mind. There was a reference to a patent in a thread here that I've since lost, but it was concerning cheddite mixtures using potassium chlorate, and petroleum jelly. It was a turn of the century patent, but one line in it stated that KMNO4 could be suitably substituted for the chlorate in the mix. That was the point that sparked my interest. Flash powder is neat, but it is still just flash powder. Making an exceptionally unsafe version of such a ridiculously common OTC energetic "for the lulz" doesn't tickle my sciencebone very much. If I'm going to risk my eyebrows, it must be something more interesting than that!
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CaliusOptimus
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[*] posted on 3-8-2012 at 21:52


Quote: Originally posted by hyfalcon  
Why waste the chlorine donor? Unless he's making colored stars that is. Try some red gum.


Just a curiosity. One that I satisfied about 10 minutes ago.

Both coarse mixtures (70KMnO4:30Fuel) burned at a reasonably speedy pace, something akin to AP star comp. Burn rate would probably be significantly faster if the KMnO4 was milled and comp bound with solvent. Zero OB would also help. I'm confident that all of these mixes would be very stable at STP, but don't take my word for it. Unfortunately I didn't have any polyethylene to try.



[Edited on 4-8-2012 by CaliusOptimus]
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Kalium
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[*] posted on 3-8-2012 at 22:06


This thread contains the patent you were thinking of, along with some useful information regarding cheddite and Sprengel mixtures: http://www.sciencemadness.org/talk/viewthread.php?tid=19712

[Edited on 4-8-2012 by Kalium]
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[*] posted on 4-8-2012 at 07:31


The only OTC solid hypochlorite is Ca(OCl)2.2H2O, used as swimming pool bleach. I have mixed this with a few fuels and some of these self-ignited on mixing, others were insanely sensitive and already ignited while a flame was near (not in!) the mixture.

Another easy to obtain compound is so-called MMS, which is sodium chlorite, NaClO2 (80% or so, the remainder being NaCl). This is nearly as useless as calcium hypochlorite. It is a little less sensitive, but still way too sensitive to make a useful mix. I tried this with sulphur, sugar and red P. The mix with red P is self-igniting, the mix with sugar also easily self-ignites, e.g. by swirling it in a piece of paper, and the mix with sulphur is more sensitive than the already very dangerous mix of KClO3 and S.




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[*] posted on 5-8-2012 at 06:40


Quote: Originally posted by Farnsworth  
.... What I do know is that both compounds are extremely reactive, often to the point of unpredictable self-initiation, when combined with a wide variety of fuels.

Hypochlorites interest me because they are one of the few compounds in the chlorate/chlorite family that is still widely available OTC. Ditto for permanganates. In the latter case I'm given to understand that KMNO4 is suitable as a component in certain sprengel type explosives or cheddites if combined with a narrow list of suitable complements. This avoids critical oversensitivity.

First question is, is this correct?

The second is a follow on to the first. Are there any known hypochlorite combinations that do NOT express the unruly hypersensitivity that normally precludes their use in energetics?.......
--Farnsworth


Something I was recently thinking about may answer your question. Sodium Hypochlorite Pentahydrate (NaClO.5H2O) . To quote: "The pentahydrate (NaClO·5H2O) is more stable; its melting point is 18° C (64°F)". Also: "Sodium hypochlorite is made commercially by passing chlorine gas (Cl2) through a cold aqueous solution of sodium hydroxide (NaOH):

Cl2 + 2NaOH → NaClO + NaCl + H2O

The pentahydrate then can be extracted by crystallization." Source: http://www.bookrags.com/research/sodium-hypochlorite-chmc/

Per another reference, to quote: "The concentration of base depends on the application, eg,~14% NaOH is used to prepare commercial strength 12.5% NaOCl solutions. Chlorination of 50% NaOH and removal of precipitated salt produces a concentrated, low salt solution (32%NaOCl, 6% NaCl), which is used as a process intermediate in Ca(OCl)2 manufacture. Concentrations as high as 45% can be obtained by melting NaOCl.5H2O crystals (mp 18 C) recovered by cooling this solution." Link:
http://www.scribd.com/doc/30121142/Dichlorine-Monoxide-Hypoc... )

More details on the preparation of NaOCl.5H2O are available in Patent 5,194,238 in which a slurry of sodium hypochlorite pentahydrate in an aqueous solution of sodium hypochlorite is formed by the reaction a 35% hypochlorous acid solution and a 40% to about 80% by weight NaOH at a temperature below about 25 C. Link: http://www.google.com/patents/US5194238

At this point it is probably wise to reference Sodium hypochlorite pentahydrate's MSDS. To quote: "Hazards: May explode from heat or contamination. May react explosively with hydrocarbons (fuels). May ignite combustibles." Link: http://www.chemexper.net/specification_d/chemicals/supplier/...

Actually, I do not find the last quote surprising as anhydrous sodium hypochlorite is very explosive (see, for example, https://docs.google.com/viewer?a=v&q=cache:p8Tx6bqxtMQJ:... ). So Sodium hypochlorite pentahydrate is perhaps a 'safer' compound given the hydration, but I would proceed cautiously nevertheless with small samples in the event of likely impurities. Note, I would strongly NOT recommend mixing NaOCl.5H2O with anything as the result could again be a hypersensitive explosive composite.

[Edited on 5-8-2012 by AJKOER]
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