Whistle Powder

[YT2095]

traditionaly this is a mixture of potassium perchlorate and either Sodium or potassium benzoate,

I got to thinking, if we strip the Na or K off the benzoate and leave benzoic acid, wouldn`t that allow for a more complete combustion with less solid product remaining?

thus you could get away with less mixture OR add more binder to make a whole array of new firework designs where pressing the powder isn`t always practical.

 

Secondly, as sodium benzoate makes the flame yellow, how about Barium or Strontium benzoate instead, it would be nice to see a rocket go with a colored flame trail!

[jdurg]

I would think that the sodium/potassium ions make the mixture a slight bit more stable. Pure organic acids and very potent oxidizers aren't exactly the safest of mixtures.

[YT2095]

it`s the Fuel (reducer) in this mix though, the KClO4 is the oxidiser

[budullewraagh]

thats what he was saying. benzoic acid is an organic acid. potassium perchlorate is the oxidizer. pure organic acids (eg: benzoic acid)+oxidizers (ie, KClO4) arent very stable

[YT2095]

aha, I`m with ya, I misread!

 

I think I`m going to have to do some Practical with this, as I can`t see any mechanism they could react with under "normal" conditions when cast.

 

assuming it fails, the Barium or Strontium adjunct may still prove interesting

[jsatan]

Aha, Bonfire night, me is starting as well,

[woelen]

If the oxidizer is KClO4 then I would not worry too much about the stability of the benzoic acid/KClO4 mixture. As far as I remember, benzoic acid is not such a nice powdery crystalline substance as sodium benzoate. So you might have problems to make a really good mix of KClO4 and benzoic acid. The latter is quite 'sticky'.

[YT2095]

well normaly the benzo componant is dissolved in ethanol that then gets mixed with the oxidiser to make the slurry for coatings (wheat or rice hulls, I use wheat as I grow the stuff anyway), but mixed in a similar way with a binder (dextrin) it should set quite nicely when cast, and the granular texture`s never going to be an issue

 

I really DO need to make some tests 1`st though, as at the moment it`s all hypothetical and needs trial (the Fun part) )

[woelen]

I really DO need to make some tests 1`st though, as at the moment it`s all hypothetical and needs trial (the Fun part) )

Keep us updated . Especially the color-part is interesting. As you mentioned, this might open up ways for making whistle compositions with other flame colors than orange/yellow.

[YT2095]

well I`ve run a few tests with my whistle composition going the benzoic acid route, I was astonished at the result, I made an equal mix with sodium benzoate and benzoic acid with the KClO4 (in the correct proportions), the sodium benzoate worked as expected, nice flash and gone.

the benzoic acid recipe did hardly a thing at all, it started melting and then caught fire like candle wax and kept going out (it was hard to light) with the occasional sparkle from the KClO4, so basicly, don`t bother, for some reacton it needs the metal ion in the benzo to work at all.

incidently the remainder of both I mixed and set fire to, that worked well also, but lots of white smoke.

now all I need to do is get my hands on barium and/or strontium hydroxides to try the other half of my idea somehow???

 

but basicly benzoic acid and KClO4 doesn`t work at all.

 

edit: as an afterthought, and since the last experiment has me down the color path instead, we can cover yellow, green and red, how about COPPER Benzoate! if my thinking is correct, this Could make a Blue whistle powder!

anyone know a way to synth this at all?

[woelen]

Try mixing strontiumcarbonate and benzoic acid with a small amount of water. Strontium carbonate can be purchased at ceramics and pottery suppliers. You might be able to make strontium benzoate with this and use that as fuel. I'm not really sure whether this method allows you to make strontium benzoate, but you could give it a try. Strontium carbonate is dirt cheap and easy to obtain.

 

Beware, that in commercial strontium carbonate there may be up to 5% of strontium sulfide. So, perform the mixing and preparation of strontium benzoate outside!

[YT2095]

a thought about the copper, if I used copper sulphate and added NaOH to make sodium sulphate and copper Hydroxide, a good wash and filter to shift all the sodium ions, the hydroxide should react with the benzoic acid?

 

I`m not sure of the copper benzoate solubility, but maybe even copper sulphate to sodium benzoate might work (providing the copper benzoate isn`t that soluble)?

[woelen]

Copper benzoate is not soluble, but you'll find it extremely difficult to get it totally free of sodium ions. Also if you make Cu(OH)2, it is extremely difficult to get it in the pure state.

 

A general rule: If a precipitate is formed of a flocculent nature, such as Cu(OH)2, then you'll suffer from co-precipitation. Together with the Cu(2+) ions, some Na(+) will be encapsulated in the precipitate, which cannot be washed out. Of course, the same holds for the sulfate ions.

 

If you precipitate a crystalline solid, then the problem of co-precipitation is much less severe.

 

So, if you want to make copper benzoate for making whistle mix, which has another flame-color than orange, try to make some potassium benzoate and precipitate that with copper sulfate. In that case you get copper benzoate with some potassium and sulfate ions co-precipitated, but these do not spoil the color of the flame.

 

I understand that you made your benzoic acid from sodium benzoate. You can get rid of sodium in your benzoic acid, by dissolving it in an organic solvent, decanting the solution and discarding any solid which does not dissolve (this contains the ionic remains of sodium benzoate) and evaporating the solvent. I'm not sure what is a good volatile solvent for benzoic acid. You could try it with acetone.

 

Even if trace amounts of sodium are left in your mix, it spoils the flame color.

[YT2095]

well benzoic acid dissolves great in ethanol, although I`m not sure about sodium benzoate (I`ll have to test it), I know Copper Sulphate is partly soluble in ethanol also, as I use this method to make Copper Chlorate.

I agree that an organic solvent would be the better choice for a "wet" reaction, although I`ve been Very succesfull in the past a removing sodium ions from floculent PPTs, it just takes ALOT of time

 

 

edit: scratch that, just tried it, sodium benzoate doesn`t dissolve in ethanol Grrrr..

[woelen]

edit: scratch that, just tried it, sodium benzoate doesn`t dissolve in ethanol Grrrr..

This is VERY good man!

 

Now, you can purify your benzoic acid very easily. Make benzoic acid from sodium bezoate and any acid. The precipitate still contains some sodium benzoate and other ionic stuff.

 

Now you dissolve your (somewhat impure) acid in the ethanol. Any insoluble matter (including remains of sodium benzoate) do not dissolve. Let insoluble matter settle at the bottle and decant the clear liquid.

 

Next, let ethanol evaporate and the benzoic acid remains, free of sodium!

 

Now, you can make copper benzoate, absolutely free of sodium as follows:

Prepare a solution of potassium benzoate by dissolving as much as possible of benzoic acid in a solution of KOH or K2CO3.

Next, add a solution of copper sulfate to this solution.

Now you get a precipitate of coper benzoate with some co-precipitated potassium and sulfate ions. These ions do no harm, because they do not spoil the flame color.

Filter the precipitate, rinse a little and let dry overnight.

 

You see? You have a perfectly doable method of preparing copper benzoate, which is absolutely free of sodium ions and you exploit the fact that benzoic acid is soluble in ethanol, while sodium benzoate is not.

[YT2095]

agreed 100%, only prob is, I have no KOH or the carbonate, well... I have a soln of it, but it has Zinc contamination (only trace so it maybe doable still).

 

I tried the All Wet method, sodium benz and Copper sulphate, nice light blue PPT that seems to like to Float on water rather than sink???

anyway, it`s been washed and filtered and re washed and filtered again (I didn`t do the magnetic stirrer on fast though, so there may be traces left, anyway it`s drying now on the convector, it`s only just under a gram, so I ecpect it usable in about an hour. I`ll post the results also.

 

oh and btw, I`de hoped not to embarass myself, but I have to re-test that sodium benz result again, you know that powder I made this morning with the benzoic acid, I MAY have used that! I know I did once by mistke, so it`s possible I did it then also (I thought it was odd having 2 different sorts of PPT, one was the KClO4) *hangs head in shame*

 

that`s what you get for mix anon white powders in test tubes without LABELS YT!

[YT2095]

update:

 

whilst waiting for the copper benz to dry, I thought I`de try KClO3 instead of the O4 with the sodium benz, remarkably similar in every respect, a little more "Crackley" and a bit easier to light, other than that, you`de not be able to tell the difference

 

the Cu benz test was equaly interesting, with the O4 the burn rate is about the same as with the Na benz, but the flame color is a brilliant white and leaves spots in front of the eyes, there is a Hint of light blue/green also.

 

same with the O3, oddly this was a quieter mix with copper than with the Na (opposite to the 1`st test).

 

an interesting point to note is that instead of the white powdery marks left as a condensate on the surface when burned, you get a Pink Copper powder instead and much less "smoke"

[jsatan]

I've got some KOH as well, you get it from the hydroponics shop.

Just to add to the colours etc, I mixed sodium chlorate with copper sulphate and sugar and that was a great blue flame, it even had a 2 tone effect on the top of the flame, must try.

[YT2095]

I tried that mix myself, the blue isn`t that good IMO, I`de imagine that the 2 tone effect would be from the mesh size of the powder, if they were a really fine powder and intimately mixed you`de get an overall single color, but like this you`ll get distinct copper and sodium containing granules that will emit individualy.

also, be VERY carefull when mixing chlorates with Sulphates, it can spontaniously ignite without warning, sodium chlorate and sugar alone is plenty dangerous too, as it`s friction sensitive

[woelen]

also, be VERY carefull when mixing chlorates with Sulphates

Is that true? Of course, you need to be careful with any chlorate mixture, but why would a sulfATE mixture be more sensitive. In fact, sulfate is rather inert. I know about the really dangerous mixes, with sulfIDE mixed in (e.g. barium carbonate from a pottery supplier, which also contains some barium sulfide). The danger of sulfide, mixed with chlorate is understandable, because sulfide is the most reduced form of sulphur. Even with sulfITE, I can imagine, but with sulfATE, no.

 

Another dangerous thing is mixing of copper salts with chlorate. So, mixing copper sulfate with pot. chlorate may be quite dangerous, because the copper ions act as a catalyst on certain decomposition reactions. If ammonium ion is present, then also the dangerous TACC can be formed.

[YT2095]

sulphates can break down too, giving sulpher based acids. it`s also rare to never that you`ll get a 100% Pure sample of copper sulphate without acid traces either, same with "pure" sulpher also, it makes them time unstable and also impact sensitive. perchlorates are immune, however "home made" perchlorates without Chlorate traces are very difficult to acheive, and I advise against that too.

 

as for Amine problem (metal powders and nitrates for instance), that`s easily overcome with the addition of Boric acid

[jsatan]

Yeah I alway watch out when I've got sulpher and ATES. etc, but it was good anyway.

It was the weed killer from wilkos, I know they put some other stuff in it to stop people making what ever out of it,

But it was fun to try.

[YT2095]

does anyone know the solubility of Barium Benzoate?

 

barium carbonate Does react with benzoic acid in hot water perfectly, but I have a Sulfide contamination that could be up to 6%, I have a precipitate, so is the clear Liquid the product and the PPT junk? is the solubility low and BOTH are good?

 

basicly a spatula of the benzoic and a half spat of the barium carbonate (contaminated) to 20ml of hot (deionised) water.

[woelen]

I expect barium benzoate to have a low solubility. If copper benzoate has a low solubility, then the barium salt almost certainly also has low solubility. So, I would expect the precipitate to be barium benzoate, contaminated with mainly unreacted benzoic acid and unreacted barium carbonate.

 

The problem of this synthesis is that both reactants are not soluble in water very well and the expected product also is not soluble in water very well. Having a really good mix therefore is difficult.

 

 

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You could try the following to see whether barium benzoate really has low solubility:

 

Dissolve a pinch of BaCO3/BaS in a small amount of conc. HCl and evaporate to dryness. This will leave reasonably pure BaCl2 with some BaSO4 and S contamination.

 

Dissolve the solid and let turbidity settle. The clear liquid above it is an almost pure solution of BaCl2.

 

Add the clear liquid to a solution of sodium benzoate. This probably will show a thick white precipitate of barium benzoate.

[YT2095]

actualy, that`s more or less exactly what I did do

 

I used potassium benzoate instead though, interestingly enough, there was no imediate reaction I had to boil the soln and leave it to cool slowly, now I have a large cluster of needle like crystals that have grown at the bottom of the test tube overnight, I`ll pour off the liquid, allow these crystals to dry and do a flame test on them, all being well I should get a nice green color, and have a way to make reasonably pure barium benzoate free of Sodium ions!