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JohnWW
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[*] posted on 5-9-2004 at 18:51


Oxomalonic acid, which Blaster thinks he made, exists (see Google). If it is stable enough to be dehydrated, its dimeric cyclic anhydride, with the formula C6O8, would be another carbon oxide. However, the anhydride does not show up on Google. I brought up the subject of carbon oxides in another organic thrread recently.

John W.
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Blaster
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[*] posted on 6-9-2004 at 02:39


Quote:

Hmmm, wouldn't it be a stupid idea to use Sulfur with KMnO4 ? On contact with moisture it could form a small amount of H2SO4, just like that its a very bad idee to add sulfur to a chlorate because ClO2 is formed witch can self ignite at high concentration.


This is rubbish! Elemental sulphur will not react this way with either oxidant mentioned.


Conversely, an excellent reply by ordenblitz. I agree with all you say.
If I was in the trade I would of course use weight for consistency and greater accuracy, especially with large quantities. Being a purely amateur firework experimenter however, volume has proved more than sufficient for me.

The fact that Mg can be obtained so fine is something new to me. Unfortunately, I am restricted to commercial laboratory grades. Being in "Nanny State" Britain, I imagine purchase of the above powders from a pyrotechnic supplier will prove impossible but I'll look into it.

Oxomalonic acid was a pure guess - I was hoping an organic chemist in the forum could help me out there!
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BromicAcid
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[*] posted on 6-9-2004 at 06:27


When I was into pyrotechnics I heard to never mix sulfur with chlorates over and over again. The theory is that commercial grade sulfur contains impurities that can cause the mix to become acidic on standing which can lead to the decomposition of the sensitive chlorate molecule which can lead to the catalyzed spectacular decomposition of the mix. Doing an Internet search brought up several pages supporting this theory.

However high grade sulfur that lacks this acid component can be somewhat safely mixed and stored with chlorates (although it is recommended to add a component that is basic, barium carbonate or other coloring agent to negate possible acid formation). Sulfur mixes with chlorates are sensitive regardless of this.

Back onto permanganates, the spontaneous ignition of this mixture upon the addition of glycerin makes total sense. Permanganate is a strong oxidizing agent and once the oxidation starts it heats up and it won't be able to stop at any stage in between, it will heat itself as it oxidizes and by then you have a hot acidic soup laying on top of a pile of strong oxidizer mixed with combustible (strong oxidizer that doesn't like the acid much anyway).

Doing a google in the groups section, particularly in rec.pyrotechnics for the properties of potassium permanganate mixtures gives many warnings and long threads on the subjet.




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[*] posted on 6-9-2004 at 08:13


I don't see why potassium permanganate shouldn't be able to oxidize S in humid condition to H2SO3 or even H2SO4.

If you think this is rubbish, please provide some reference.




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[*] posted on 6-9-2004 at 09:41


Bromic,

The problem with sulfur and chlorates is two fold. Early in the past century before the advent of vulcanized rubber for tires, obtaining sulfur free from acid residue was more difficult making the possibility of a pyrophoric mixture "acid+chlorate" more possible.

S+xCLO3 results in a mixture that is very friction and impact sensitive even when free from residual acidity. Many budding pyros, including myself some 30 years ago, have heard the snapping and popping while mixing the two by mortar and pestle. Some were not as lucky to be given a warning.
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Blaster
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[*] posted on 6-9-2004 at 12:21


Ok, firstly the likelihood of sulphur being oxidised at room temperature by the KMnO4 is very small given that the reaction of pure O2 and sulphur to form SO2 does not occur below 260’C and the formation of SO2 from MnO2 and sulphur also requires a high temperature ie. SO2 has a high enthalpy of formation from its elements.
I appreciate that these are not aqueous solution examples but I’m unable to find a specific reference with permanganates. It could be calculated with heats of formation I have no doubt.
Disregarding this, even assuming that SO2 could be formed with consequent production of H2SO3 or H2SO4, the reaction would result in the formation of K2SO4 + MnSO4 under acidic aqueous conditions (Chemical Elements and their Compounds, Sidgewick Vol II p.1269).
Permanganic anhydride is very endothermic, requiring both strong oxidising AND dehyrating conditions for its formation. These conditions could not be met in a moist atmosphere. It’s a similar story for the chlorate and sulphur mix.
The presence of impurities forming acids that Bromic quoted is interesting. Without specific details I cannot comment on this but I’m guessing that moisture is not a prerequisite.

That’s a brief theory, here’s my experience in practice. I have prepared chlorate based black powder (no nitrate at all in the mix) which I use for underwater fuses and kept it in a damp garage for several years – unsealed because of the risk of friction ignition (I agree once again with ordenblitz here). There is no evidence of degradation. If water is added in any quantity there is no reaction even on standing. Same again for the flash powder, although this does deteriorate due to oxidation of the Al powder over time.

Has anyone tried red phosphorus and KClO3, or better still dissolving yellow phosphorous in CS2 and allowing the solvent to evaporate after pouring it on KClO3, now that IS a dangerous mix!

[Edited on 6-9-2004 by Blaster]
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chemoleo
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[*] posted on 6-9-2004 at 14:11


On this issue, did you even note that sulphur smells??? It doesn't smell of H2S, no, it smells of SO2. Just take a whiff at your S- jar, and you will notice it too.
For all practical purposes, S does naturally contain a small amount of SO2 (unless, say, you were to melt and crush it right before use, under argon/N2 atmosphere)




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[*] posted on 6-9-2004 at 15:00


Quote:
Originally posted by Blaster
Ok, firstly the likelihood of sulphur being oxidised at room temperature by the KMnO4 is very small given that the reaction of pure O2 and sulphur to form SO2 does not occur below 260’C and the formation of SO2 from MnO2 and sulphur also requires a high temperature ie. SO2 has a high enthalpy of formation from its elements.




This isn't meant as a flame, but maybe I should correct a few things here. In order to ignite, only traces of acid have to be present. The reaction of O<sub>2</sub> with S to form SO<sub>2</sub> and SO<sub>3</sub> is exothermic (very low enthlapy), and , if I did the math correctly, will always happen in small amounts above absolute zero. The reaction with oxygen may be slow because O<sub>2</sub> is a weak oxidizer, but it will happen much faster with a stronger oxidizer like KMnO<sub>4</sub> (where the two chems touch). To get an idea of how powerful KMnO<sub>4</sub> is, think about this: keratin will not be oxidized by oxygen very quickly (if at all), but if KMnO<sub>4</sub> is added, it will be almost instantaneous. That's what happens when you spill a KMnO<sub>4</sub> solution on your skin.
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Blaster
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[*] posted on 6-9-2004 at 15:22


My mistake re: enthalpy of formation - I should really have said activation enthalpy.
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[*] posted on 6-9-2004 at 15:55


Ordenblitz said:
Quote:
Many budding pyros, including myself some 30 years ago, have heard the snapping and popping while mixing the two by mortar and pestle.


Now thats a dumb thing to do! I sure hope you dont do that anymore. You will lose a hand or your face if you do. Never grind or roughly mix any flash comp.

(again sorry vulture if this is straying too far, but I thought it pertinant to add a safety warning)

[Edited on 6-9-2004 by fvcked]




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ordenblitz
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[*] posted on 6-9-2004 at 17:49


Blaster said:
Quote
--------------------------------------------------
Has anyone tried red phosphorus and KClO3,
--------------------------------------------------

I believe this combination is known as Armstrongs Mixture. It's sensitivity to impact, friction and just about anything else including dirty looks is only slightly better than NI3.

(But as Bromic has pointed out this was his intended point )

Fvcked said:
Quote
--------------------------------------------------
Now thats a dumb thing to do!
I sure hope you don't do that anymore.
--------------------------------------------------

Thanks for your concern fvcked, but I believe I mentioned that my sulfur/chlorate incident happened some 30 years ago. I was about 11 years old. I'm fairly certain all of us at one time or another have done some pretty stupid things especially in our youth. These mistakes and certainly our successes do shape our lives and sometimes our futures. My younger days cemented my love of pyrotechnics and chemistry such that it was my only logical career choice and has been for the last 18 years.

I was especially amused by your warning about magnesium in combination with nitrate oxidizers. You might be surprised to know that 95% of all indoor theatrical pyrotechnics are combinations of the above. Strontium nitrate with magnesium being the most useful for airbursts, flash pots, concussion and a myriad of other amusing effects.

Regarding that earlier post… Linseed oil fell out of favor in the 50's as a protective coating for magnesium. Typically the only time Mg needs passivation is when used with ammomium perchlorate. Potassium dichromate is employed for the conversion coating for that purpose.

[Edited on 7-9-2004 by ordenblitz]
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BromicAcid
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[*] posted on 6-9-2004 at 17:58


Quote:

I believe this combination is known as Armstrongs Mixture. It's sensitivity to impact, friction and just about anything else including dirty looks is only slightly better than NI3.


He was just saying that to prove there are more dangerous mixes out there, expecially when he suggested a saturated solution of white phosphorus in carbon disulfide poured onto chlorate.




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[*] posted on 7-9-2004 at 00:48


Just to add a final bit of weight to my above theory, I mentioned I'd added water to chlorate black powder and the flash powder with no reaction. I've now tried the same with boiling water and again nothing for both mixtures. Then I tried adding 10% H2SO4 to both - still nothing, and finally boiling 10% H2SO4 and even then nothing. I rest my case for the moisture theory!


Odenblitz I once again agree with what you say - the risky things I have done in my time and still do to a certain extent 20 years on (eg. ethyl perchlorate) would make most people shudder. I happen to enjoy it!
An example when I was a kid with the red P/KClO3 mix - I mixed it with a stick on the floor and then rode my bike over it - I was blown a foot into the air!

Great choice of career btw, any vacancies? I have lots of experience!!!
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[*] posted on 7-9-2004 at 14:55


ordenblitz said:
Quote:

I was especially amused by your warning about magnesium in combination with nitrate oxidizers. You might be surprised to know that 95% of all indoor theatrical pyrotechnics are combinations of the above. Strontium nitrate with magnesium being the most useful for airbursts, flash pots, concussion and a myriad of other amusing effects.


The Mg reduces the nitrate and forms other chemicals that I dont care to go into right now, but they do make the mixture heat up and/or self ignite on rare occasions. And as for you saying that "everyone uses it", well many people use AP, and thats not safe. I am sure someone can elaborate for me on the reaction but as for now, im going to sleep.




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vulture
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[*] posted on 8-9-2004 at 05:25


Nitrates + Al + moisture ----> alkaliamines, which are strong bases and react exothermically with aluminium.



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[*] posted on 8-9-2004 at 10:18
Armstrong's mixture


Rift valley, I couldn't help but laugh about your post with conventional flash.
I also think your Mom is as cool as mine was when I was growing up !
It's been over 30 years since I blew my eyebrows off while making
Armstrong's mixture. All my mother could do was laugh her ass off upon
seeing me without my eyebrows ! The only other thing she said is
"YOU'LL LEARN !". Funny thing is that my stepfather was a narc in the
U.S. Coast Guard and didn't mind me making my own shit ! I pissed him
off every time my friends and I would sneak over the border into Canada
to get the highly illegal fireworks that were banned in Maine ! And only
because Maine said they were illegal ! It's nice to have supportive parents
but don't push your luck. Even parents with a more liberal attitude
towards your "research" have their limits. Enjoy your youth but don't
kill yourself in the process, and always make sure you have lots of fun !




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[*] posted on 9-9-2004 at 09:08


Quote:

Nitrates + Al + moisture ----> alkaliamines, which are strong bases and react exothermically with aluminium.


Vulture, I don't follow this. Could you elaborate?
Are you saying that NaNO3 is converted to NaNH2 this way??? which in the presence of moisture of course immediately forms NH3 and NaOH? So really what reacts is the NaOH, forming aluminate? A direct conversion to NaNH2 sounds unlikely to me though (simply becuase it is so highly reactive), even if the NaNH2 is only an intermediary.... comments?




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[*] posted on 4-12-2005 at 14:30


Blaster had mentioned white P and chlorate, I have a chemistry demonstartion book that makes mention of this( and I got it at chapters only a year ago, with actually interesting demonstrations in it....how rare is that:o)

Quote from book:
"You place a few drops of a solution of yellow phosphorus in carbon disulfide on a 5 grain tablet of KClO3 which is resting on the base of a rignstand. In 15 minutes the solvent will have evaporated and the tablet is ready to be exploded. Touched with a metal rod from a ringstand, the explosion is violent"

I am rather surprised that it does not just spontaneously explode once the CS2 has evaporated....

Also, in keeping with this threads topic of unconventional flash powders, I just tried sodium peroxide-nonahydrate(self made) with Mg filings, aprox 1:1 by volume(I know not reliable). The burn rate was not incredibly fast, about the same as decent BP, but was incredibly bright, I had blind spots despite wearing UV goggles(nothing has ever caused this before when wearing these goggles)




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[*] posted on 9-12-2005 at 18:08


That would be the oxygen developed by the Na2O2 reacting with the magnesium and burning with that high intensity flame. There was no characteristic yellow color to the mix then?

It is hard to make a fast sodium peroxide mixture since the material is very hygroscopic and quite tough to grind.
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[*] posted on 9-12-2005 at 18:57


Oh the flame was yellow, the brightest sodium orange I have ever experianced.:)

The sodium peroxide was also not ground well, just crushed with the metal spatula, after taking it out of its vial. My sodium peroxide is not in large granules, it is rather fine crystals. I followed the procedure Polverone got from the inorganic synthesis books,(there is a thread somewhere here on that), but unfortuantly I spent my time searching for that synth in the inorganic synthesis volumes at the library, before checking the forum(and the inorganic synthesis volumes lack any real indexing method, that I know of). I also only dried it over CaCl2 for a week, not concentrated sulfuric, and only used half the recomended ammount of etOH they suggested for washing.

Also I have been unsuccessful in doing the sodium peroxide/kleenex hypergol, but likely because I was only working on a small scale.

EDIT: I never really experianced much hygroscopicity, even after leaving a small pile in an open beaker overnight, but by the next day it had likely become sodium carbonate as the peroxide reacts with the CO2 in air. I should test that...and I will go leave a bit out right now!

[Edited on 10-12-2005 by rogue chemist]




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[*] posted on 9-12-2005 at 19:03


Anybody notice that according to brauer, potassium aurate is said to decompose to something like Au, K2O and KO2? If there was an easy way to separate these, potassium superoxide would be fun to play with :)
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[*] posted on 9-12-2005 at 19:30


Fun perhaps, but expensive too! At $510 an ounce for gold, it would easily be one of the most expensive ways to get potassium oxides. Then again, you do get your gold back too :-)
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[*] posted on 9-12-2005 at 21:27


For my flash I use Potassium Permanganate and Aluminum. My Aluminum is 8 mesh. I am thinking of using this mixture as a rocket fuel igniter as it burns "slower" compared against other finer aluminum/magnesium.

Anyways I never bother with the sulfur addition as it makes a fairly nasty smell.


[Edited on 10-12-2005 by DeAdFX]
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[*] posted on 10-12-2005 at 05:56


8 Mesh? That's very coarse for flash powder.
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[*] posted on 10-12-2005 at 08:22


Powder... that's more like gravel.

[Edited on 10-12-2005 by ordenblitz]
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