Sciencemadness Discussion Board - Gunpowder (Potassium Chlorate) from Bleach

Gunpowder (Potassium Chlorate) from Bleach

EliasExperiments - 4-12-2020 at 05:00

Hi, in this video, I tried to make some gunpowder from bleach:

https://youtu.be/ooL3IAjx8jU

My yield at 20 % was quite low however. Does anybody know why that could be? I am pretty the largest part of the available poatassium chlorate crystallized from solution.
Could it be because the Bleach is old? I thought it would just decompose into sodium chlorate upon aging. Or does it release oxygen?

Antigua - 4-12-2020 at 05:02

This reaction is notorious for very low yields. You should better look into chloride electrolysis if you're after some valuable amount of chlorate. Woelen has a really nice writeup about it on his page.

Fyndium - 4-12-2020 at 05:28

Apparently a large portion will remain in the liquid, even though relatively small percentage concentration, but the liquid volume is so large. Same issue goes with perborate process. It could possibly be improved by using supersaturated reaction mixture where a solid form of both exists at the same time and the reaction proceeds as the reactants are dissolving on the go. With bleach, obviously higher concentration of hypochlorite would be the thing - here the calcium hypochlorite metathesis steps in as a feedstock. For example where I live, sodium hypochlorite is sparsely available over 3-5% concentration and in small bottles costing a lot and larger canisters needing hazmat shipping will rocket the price, but calcium is sold by the kilo. Not sure if the conversion to chlorate could be done directly from calcium?

[Edited on 4-12-2020 by Fyndium]

Maurice VD 37 - 4-12-2020 at 08:28

I would be cautious about the competence of the experimenter. He says that NaOCl can be read "N H O C L". That is wrong. Reading correctly this formula is "N A O C L".
Furthermore heating bleach may produce potassium chlorate by cooling the solution. But gun powder made with chlorate is known to be dangerous. On the contrary, gun powder made with potassium nitrate KNO3 instead of potassium chlorate KClO3 is not dangerous.

Antigua - 4-12-2020 at 09:06

Now I watched the video and the german guy got 20% yield too. So what's wrong? You got the same awful yield as him, you both used the same method, you both turned some NaOCl into NaCl and oxygen and you both didn't disproportionate the hypochlorite fully probably. And there must be still a lot of salts in the filtrate, KClO3 is weakly soluble but not insoluble (considering we have 25L of water there!). Solubility of KClO3 - 4.46 g/100 mL (10 °C) 8.15 g/100 mL (25 °C). It's far, far away from insoluble!

greenlight - 4-12-2020 at 10:59

Two things:

It would definitely be worth designing even a small electrolysis cell if you want to make a useable amount of potassium chlorate. There are many internet pages that go into detail on construction of these cells and they are not that hard to run.

This guy has good skills with purification of compounds but it stops there. What he has made is not gunpowder. It is a burst mixture called H3 used for larger diameter pyrotechnic shells which is usually mixed very carefully (Not in a mortar and pestle) and then coated onto rice hulls or the like.

He should not be using the word chlorate and gunpowder together as it gives people with limited knowledge stupid ideas which can lead to limited fingers to count on. Gunpowder uses potassium nitrate, sulfur and charcoal. You cannot substitute potassium chlorate as the oxidizer as this creates an unstable friction sensitive mixture when in contact with the sulphur which you cannot process the same way you can normal gunpowder mix. There's a reason that sulfur isn't ever included with chlorate compositions.

EliasExperiments - 4-12-2020 at 11:40

@Antigua: I will do a chlorate electrolysis in the future, but first I wanted to use up the bleach I got. I don't think there was any significant amount of chlorate in the filtrate, because it is satureated with other salt like KCl and NaCl. KClO3 has the lowest solubility of all of them. Evaporating it down further only caused other salts to crystallize.

@Fyndium I don't think there is a lot left in the filtrate for the reasons stated above. Calcium hypochlorite might be a good idea, but I think electrolysis is better then buying calcium hypochlorite.

@Maurice VD 37 What you are saying it not very nice, but anyway. Yeah that was totally stupid for me to missspell it. That is why I have written it out in the video. Thank you for pointing that out, I didn't even give it a second thought. Gunpowder with just charcoal and chlorate is not really more dangerous as far as I know. Only when you add sulfur to chlorate mixtures it gets more problematic.

@greenlight Getting the most chlorate for the least amount of effort was not the point. The point was to create an entertaining educational video, while using up my remaining bleach.
This is gunpowder, just not the most commonly used composition. You can also call it H3, but that doesn't make it less gunpowder. If someone who is stupid tries stuff like that anyway I can't be made responsible for everything. You don't need to try such time consuming experiments to lose fingers. A regular kitchen knife is enough...

You can substitute the nitrate for chlorate if you do NOT add sulfur! That's the whole point.

MidLifeChemist - 4-12-2020 at 16:37

Quote: Originally posted by EliasExperiments

This is gunpowder, just not the most commonly used composition.

Elias, trying to make gunpowder from potassium chlorate actually has a very interesting history. In fact, as you may know, potassium chlorate is also known as "Berthollet's salt".

https://www.sciencephoto.com/media/764614/view/berthollet-s-...

I think you are going to see more comments on the video, saying that it is not considered gunpowder. Just a prediction.

[Edited on 12/5/2020 by MidLifeChemist]

greenlight - 5-12-2020 at 11:38

Quote: Originally posted by MidLifeChemist

Quote: Originally posted by EliasExperiments

This is gunpowder, just not the most commonly used composition.

I understand what your trying to do and it is a good method if an amateur chemist doesn't want to do additional electrical research and spend the extra time and money to make a chlorate cell.

A lot of people are going to be saying its not gunpowder and i do agree. There was an attempt linked above from midlifechemist about a man attempting to make chlorate gunpowder which had disastrous results (explosion and loss of life of family members) upon the milling of the composition which is quite interesting. This resulted in chlorate being used in pyrotechnics only afterward.

H3 makes a strong burst and when placed in a gun barrel it does exactly that. The gun barrel will inevitably rupture.

Quite hard to call something a gunpowder when it cant even be used as a propellant in a gun.

Fyndium - 5-12-2020 at 15:02

Generally people interested in pyrotechnics and energetics should be paid extra caution about what they are really dealing with. Something that cuts off their fingers starting from 5000m/s is not something to trifle with. In this context, the extra H's or gunpowderie like lower high explosive chlorate is matter of semantics.

Anyway, better call it a pyrotechic mixture. These are not suited for any sort of controlled projectile ejecting applications, unless exclusively specified.

I'm quite aware of getting (per)chlorate much easier with an electrolytic cell, having done so in small quantity with PbO2 electrodes and I actually dug up my old transformers and rectifiers planning to take it as a project for the more boring days, but here the concept was that of if chlorate could be made out of seemingly easily available and cheapish bleach. Concept being, you go and buy a bag of this and bag of that, mix'em up, boil, cool, filter and dry. Close to zero lead-in costs and if you're productive, you can get this all done in a pastime.

However, do not underestimate the solubility matters. Few grams per 100mL is not much, but it quickly eats your yields when the process volume skyrockets. The perborate method I worked with requires 10 liter volume for hundreds of grams of reagents, and that will alone consume 200g of the theoretical 600g yield, a 33% (and this is not counting in the separation and purification losses and unreacted or side reaction stuff) which I would begin to call for a nope, unless it is only method available or still cheaper than alternatives.

That is, 200 to 700 grams of potassium chlorate remaining in the solution, in ideal conditions. Co-precipitation of other salts must be taken into account, if their solubility decreases below treshold, as they will come up as impurities.

I still find this method viable, especially if it works with specifics I stated in my earlier post. Potassium chloride and calcium hypochlorite (and sodium compounds) are easily and cheaply available and allow for a much higher concentrations, reducing the losses from dissolved remains.

For example, the bleach chloroform method is practically unuseable as it needs several kilograms of reagents to obtain even few hundred mL of chloroform. The topic floating here earlier specified a synthesis:

https://www.youtube.com/watch?v=heqMdYqqMGs

Which uses very reasonable reaction volumes producing useful quantities of chloroform. Meanwhile, people do it with 5% bleach, using 10 gallon basins to extract few hundred mL of impure product. Youtube is half-full of videos titled "synthesis of x" where people try a synthesis and work out few drops of wanted product with 3% yield. Few and far apart are the videos where the synthesis is actually depicted in a clear, logical way with all the tried and true methods and the yield is closer to 90 than 30. That's really scales away from useful yield.

Yes, I'm a big fan of process economics. It's not that you make the synthesis work, it's the one who gets the yield closest to 100%. A huge, sometimes even better bonus if you can recover/recycle the waste product.

Not arguing here. Just thinking. I believe we all can agree to the former paragraph.

woelen - 6-12-2020 at 02:12

After reading this thread I have one comment: Do not use the term "gunpowder" for a mix of KClO3 and whatever reductor. Gunpowder is a mix of KNO3, C and S. Normally I can be somewhat lax on naming issues, but in this case, I think that there is an unacceptable risk that people without experience of knowledge read the word "gunpowder" and think they can safely crunch, hit or otherwise crudely process mixes of the chemicals, regardless of what they are. This will lead to ignition, or even explosions, where people do not expect them.

I remember my young days at an age of 16, when I mixed KNO3, sugar, sulfur, carbon and all other kinds of flammable things and I used hammers to crunch the stuff, used files to scrape things and mixing things at the same time, and so on. I only had KNO3 at that time and knew nothing of safe practices (it was pre-internet time, beginning of the 1980's). Never had an accident though. If I would have done that with KClO3, my life could have been quite different from the life I now have . . .

metalresearcher - 6-12-2020 at 03:14

Quote: Originally posted by woelen

After reading this thread I have one comment: Do not use the term "gunpowder" for a mix of KClO3 and whatever reductor. Gunpowder is a mix of KNO3, C and S. Normally I can be somewhat lax on naming issues, but in this case, I think that there is an unacceptable risk that people without experience of knowledge read the word "gunpowder" and think they can safely crunch, hit or otherwise crudely process mixes of the chemicals, regardless of what they are. This will lead to ignition, or even explosions, where people do not expect them.

I remember my young days at an age of 16, when I mixed KNO3, sugar, sulfur, carbon and all other kinds of flammable things and I used hammers to crunch the stuff, used files to scrape things and mixing things at the same time, and so on. I only had KNO3 at that time and knew nothing of safe practices (it was pre-internet time, beginning of the 1980's). Never had an accident though. If I would have done that with KClO3, my life could have been quite different from the life I now have . . .

Nice story.
For me the same. I did this as well when I was 16. KClO3 was readily available at the local pharmacist who only warned me when I purchased another 500g.
I mixed a bit with sulfur (!) and put it into a 10mm diameter and 200mm long aluminum tube. Nice fireworks....
I had luck ...

[Edited on 2020-12-6 by metalresearcher]

MidLifeChemist - 6-12-2020 at 07:29

Quote: Originally posted by woelen

I remember my young days at an age of 16, when I mixed KNO3, sugar, sulfur, carbon and all other kinds of flammable things and I used hammers to crunch the stuff, used files to scrape things and mixing things at the same time, and so on.

Yes, that was me too, I created the same mix at that age and enjoyed watching it burn and spark.

TriiodideFrog - 12-12-2020 at 20:27

You can try to make a chlorate cell.

https://woelen.homescience.net/science/chem/exps/miniature_c...

Woelen has a great description on how to build one.

macckone - 14-12-2020 at 11:29

I am going to interject here.

There are in fact chlorate gunpowders.

What it isn't is black powder or smokeless powder.
Black powder being KNO3, sulfur and carbon.
smokeless powder being single, double or triple base with most small arms using single base which is nitrocellulose.
Ie. gun cotton.

Chlorate based gunpowder is used in fireworks as a replacement for black powder in some formulas for specific effects.

As a side note chlorate and sulfur don't mix.
They tend to become unstable as sulfur oxidizes to acid and releases chloric acid which is unstable.

https://www.jstor.org/stable/27757116?seq=1

There are also a large number of pyrotechnic forums which describe the chlorate based powders.
In addition there is a formula for the old powder used in actual firearms floating around somewhere.