Dear ScienceMadness,
I'm new here, so i apologize for any unintentional breaking of formalities.
My question is related to pyrotechnics, so it seems the "Energetic Materials" forum is closest to my topic.
It's a known fact that solutions of Methanol, CuCl2 and chloroform/DCM burn with a beautiful blue flame due to the CuCl species being formed in the
flame.
Sadly these solutions are quite difficult to store in anything other than glass as CuCl2 reacts with Stainless Steel (SS) and few plastics are
resistant to the charms of chloroform/DCM.
I've tried complexing the copper with NH3 and Citric Acid to prevent the Cu/Fe reactions on SS and while these work, they require a lot more of the
chlorine donor to get the blue. This solves one problem, but exaggerates another.
So my question. Are there other radiating species other than CuCl that give blue? Maybe sulfur or one of its compounds? j_sum1 - 21-11-2016 at 00:53
Welcome to the board. Stick around and enjoy the wealth of good information here. (Sadly little from me but I am getting better.)
For the record, all thread starters without a reference belong in beginnings. Take the time to read the FAQ and read a few threads to find out how
the place works. Because of the science focus and the consciousness that we are building a science reference, etiquette is different here from other
boards.
In answer to your question(s) implied and stated...
I did not know DCM was used in such a mix -- my experience is that it does not really burn. Do you really need it?
For storage, glass or plastics are used extensively for ionic substances. Most of my liquids are in the vessel that I bought them in. It seems to
work.
Search the site for pyrotechnic colours. You will find lots to read -- including a post in the last week on firework recipes. There are a few here
who are experts in the field and will help with specific questions once you have read up. For flames, I think you have hit upon the most common blue
that is used. There may be other possibilities but CuCl2 will take quite a lot of beating. For improvements I suggest adjusting your ratios and
burning conditions before you look for a different substance. Bert - 21-11-2016 at 01:19
You will not enjoy breathing the gasses coming off that blue fire mix when it burns- Likely to include phosgene, carbon monoxide, HCl (and a bit of
the unburned methanol to metabolize into formaldehyde in your liver...)
Why do you want to produce blue fire... A classroom demo? Outdoor display work? Stage/proximate special effects?Chemetix - 21-11-2016 at 01:37
Blue is undoubtedly the most difficult colour to produce. And you are on the right track with Cu(I)Cl, the use of DCM is also on the right track.
Cu(I)Cl
dissociates into Cu atoms and Cl at fairly high temperatures which give a neutral spectrum. The Cu(I)Cl that remains undissociated give the required
spectum emissions between 420-500nm. So a source of Cl to keep the atomic Cu as Cu(I)Cl is as important as keeping the temperature in the right range.
In pyro formulas the chlorine source is usually hexachloroethane. Sawdust or cellulose is use to lower the temperature. But pyro formulas are powered
by chlorates and perchlorates so the temp is going to get hot.
It remains to find a copper salt that will stay as Cu(I)Cl in the flame.
Cu oxalate and DCM perhaps. But DCM burns only under strong persuasion, perhaps an alcohol, ether or crown ether needs to be there to sustain
combustion and complex the Cu. OH radicals from the combustion of the ether shouldn't be a problem because the CuOH and CuO behave similarly to
Cu(I)Cl with their emissions.
Colouring a burning flame can be free of the hassles of contamination from other ions that pyro formulas suffer from.
I'm interested in what you come up with because I dabbled with this problem and never found a really good blue.CHEMxpl - 21-11-2016 at 05:15
what do you want to make ?
here's some firework blue recipes:
Blue star :
For 100 gram batch
Fine potassium nitrate....55gm
black copper oxide....20gm
pvc powder......15gm
charcoal....5gm
shellac....5gm
dextrin...+5gm
primed with BP
you can also add +5gm copper oxide for deep blue.
Blue Fountain
Granulate the mixture with a small amount of alcohol. Let dry and press into tubes. Very slowly burning mixture. Don’t substitute shellac with red
gum.
In pyro formulas the chlorine source is usually hexachloroethane. Sawdust or cellulose is use to lower the temperature.
Hexachloroethane is used with Zinc oxide and Aluminum for white smoke, it is not used much for colored star chlorine donor-
HexachloroBENZENE was used, and dechlorane. More common now are things like chlorinated isoprene, saran resin, chloro wax, double chlorinated PVC
powder. In the really old days, mercurous chloride (Hg2Cl2, calomel) or even sometimes ammonium chloride (poor choice with chlorates!) were used
Sawdust shows up in older lance formulae, but not so much in stars. Stearine, lactose, hexamine are cooler/slower burning fuels more often used to
keep blue stars from overheating and going green. Copper benzoate, as both fuel and colorant. Red gum or shellac for auxilary fuels and sometimes as a
binder too.
But OP is after a liquid fueled flame effect, AFAIK. Very different requirements. Ghost mines or such?Amos - 21-11-2016 at 08:06
If you have a solvent in mind for your use that can also dissolve ammonium chloride as well as the copper(II) chloride, ammonium chloride increases
and deepens the blue coloration of flames that would otherwise lean more toward green if CuCl2 was used alone.Herr Haber - 21-11-2016 at 09:23
The way I understand it, OP isnt looking for a pyrotechnic composition and just wants to make a blue flame.
If you want to get a blue flame from an alcohol burner (as seen on youtube and chemistry classes all around the world) you already got the usual way
of doing it.
I've read here and there that CuOCl can also be used but never tried it myself.
What I did try, (but not in solution as I think you are trying to do) is to lower the burning rate of a composition by adding a fuel that doesnt burn
as hot as Mg or Al. I tried Hexamin with really good results.
I made some flares using KClO4 and NH4ClO4 as the oxydizers and used CuO and CuCl2.
I remember being disappointed in the NH4CLO4 compositions. CuO also didnt give the results I expected.
I didnt go very far with these experiments, I made only 2 flares of each composition, right in the cave where they were tried and probably washed out
the blue with too much aluminium.
Anyway, back to hexamin! Why not give it a try in addition of a copper salt and a chlorine donor ?Bert - 21-11-2016 at 09:37
Try the ammonium perchlorate with Copper benzoate, bound with nitrocellulose lacquer.
There is a purple analogue too, with a bit of Magnalium fuel and some Potassium perchlorate, Strontium carbonate, hexamine and Potassium dichromate to
protect the Magnalium.
I have made both. Don't make them with the same equipment/in the same work space used for chlorate stars, of course.
[Edited on 21-11-2016 by Bert]Melgar - 21-11-2016 at 09:56
Methanol + Boric acid is always a fun one too.Marvin - 21-11-2016 at 11:19
Tripyrovinyl, I've not heard of those liquid mixes. Copper (II) Choride in methanol I know, but what I've seen first hand wasn't too impressive.
Off the cuff, Caesium produces a 'sky blue' but it's probably disappointing from a pyrotechnic point of view. I've never heard of a pyrotechnic
mixture try to use it. S2 does make a nice blue, but the only ways I've seen produce it well need gas phase mixing and I'm not sure of the
purity of the blue when the light gets intense. A liquid you can just ignite would not work, it's too weak with air as an oxidiser. And of course
there is the weak C2 we know from gas flames.Chemetix - 21-11-2016 at 12:13
I was brazing with an Oxy LPG flame and had some Indium as part of the electrode solder or composition. There was a serious blue given off. TIG
welding also gave off a blue, (but a crap weld).
To see if it was the Indium, I put a torch flame to the pure metal and it confirmed that indium was responsible.
Putting it into a liquid flame formula might work. But which salt of indium; it might need the indium atom and at a high temperature.
I am interested in producing liquid colored flames.
The blue I mentioned using CuCl2, MeOH and chloroform or DCM is quite spectacular. If the mixture doesn't contain enough of the chlorine donor, the
color becomes opaque.
Sadly this mixture probably produces a number of nasty compounds as Bert mentions, so definitely not suitable for indoor use.
I have tried using NH4Cl instead of chloroform/DCM, but this does not produce the same spectacular blue. This is probably due to the low solubility of
NH4Cl in MeOH.
The CS2/N2O reaction does produce a nice blue, but the hazards of using CS2 and N2O seem a bit extreme. Maybe there are other sulfur compounds that
could be useful? Do thiols burn with a blue flame? Probably smells like s..t.
CsCl produces a purple flame.
Chemetix - 21-11-2016 at 17:04
Just did another quick test, indium gives rich purple blue flame but in a H2 flame nothing. Indium oxide might be the species emitting the colour.ariep641514 - 4-1-2020 at 12:49
Same problem, i make methanol, metylene chloride and copper sulfate to produce cyan flame, but the problems it cannot store in aerosol cannister, in
1 week the flame become more pale blue near to opaque flame.
Any sugesstion to stabilize copper salt in can/tinplate container?Fery - 5-1-2020 at 11:50
ariep641514 couldn't Cu2+ react with the metal of can so the concentration of Cu progressively decreases?
If you store it in a plastic bottle, the same problem?Bedlasky - 19-10-2021 at 19:54
[Cu(dien)2](ClO4)2 and [Cu(tris)4](ClO4)2 produce nice blue flames.zed - 20-10-2021 at 01:48
Stabilization would be nice, if possible. Though I would proceed with caution.
Copper complexes, sometimes like to "simplify" themselves.
They generally aren't as sensitive as Complexes of Silver or Gold, but some Copper Salts can be detonated.
You mentioned a Copper Salt, and treating it with Ammonia. You may remember that Copper, Ammonia, and Nitrate.... Form an explosive material.
Hmmm. So, you are wanting to ignite Copper in a flammable solution, sprayed as an aerosol? Cool idea!
Would Chrome Plating the insides of your Aerosol cans, solve the problem?
Would Anodized Aluminum hold up?
How about, if you plated the Stainless with Copper?
There are also Teflon "paints" available. Spray 'em on the desired metal surface, bake it in an oven for a while, and "Bingo"! Chemically
resistant container.
[Edited on 20-10-2021 by zed]macckone - 20-10-2021 at 08:23
Isopropanol has a more blue flame than methanol which is close to transparent.
Acetone which is the first step in isopropanol combustion produces more yellow.
From an OTC standpoint, Isopropanol with copper (II) chloride seems doable and some hydrochloric acid to make it slightly acidic to add some chlorine
ions. I am curious what perchloroethylene would do to the flame color.
I am looking as something like this for halloween.
I was going to do green and red because those are easy.
Adding some blue lanterns could be cool.
[Edited on 20-10-2021 by macckone]Fantasma4500 - 22-10-2021 at 04:12
ammonium perchlorate with copper benzoate huh, why not just copper ammonium perchlorate? i believe thats reasonably safe- unless youre caught with it
i recall messing around with ammonium perchlorate and super fine copper dust, it gave off some extremely toxic chlorine-compound fumes, so that can
work too
isopropyl nitrite burns with a very pale flame, so that might work for fuel if you dont wanna use methanol
i wonder if you could somehow tweak methyl borate into burning blue? like some odd kind of mixture, were dealing with specific nanoparticle sizes of
light here
if corrosion of the container is your worry, just use a thicker piece of metal, or maybe even aluminium, you could do an lantern with aluminium + HCl
+ CuCl2 and have it burn blue for a long time, modifying the HCl concentration to fit the gas evolution rateHerr Haber - 22-10-2021 at 09:21
I thought about testing ammonium perchlorate with hexamine and a copper salt.
