Sciencemadness Discussion Board - Copper (II) chloride - green flame for fireworks

Copper (II) chloride - green flame for fireworks

xfusion44 - 25-9-2014 at 18:18

Hi!

Long time ago I've made some copper (ii) chloride and it makes nice green color, when exposed to flame. I thought, that this would be excellent addition to smoke bombs (with KNO3 and sugar), to make green colored flame, coming out of reaction mixture. Today I've tested this: I mixed some CuCl2 powder with KNO3 and sugar. Then I've set fire to it and it didn't want to change the color of the flame

It was still white and little violet, because of potassium in KNO3, but I don't know why it didn't work. I've also tested it mixed with ethanol and the results were same - still didn't work. It only works, when I put small amount of CuCl2 on mixing rod and expose it to flame. I also made some LiCl, which also can give nice red flame on mixing rod, but I don't even know, if it's worth trying it with KNO3 and sugar, since I would probably end up with same results as for CuCl2. Do I need different compounds to make colored flame for fireworks, or something? I also found this site, which doesnt mention CuCl2 as being colorant for fireworks: http://en.wikipedia.org/wiki/Pyrotechnic_colorant

Maybe this would be the reason? I think, it doesn't work, just because it's mixed, not just held in flame.
Any help would be appreciated

And please, sorry for my english.

Best regards, xfusion44

[Edited on 26-9-2014 by xfusion44]

careysub - 25-9-2014 at 18:41

You really need to invest in a book on fireworks, where these issues are explained in excellent detail.

If you have a subscription to Scribd you can read Dr. Takeo Shimizu's "Fireworks: The Art, Science, and Technique", a truly monumental scientific (not just practical) work. Looks like it is a $130 purchase otherwise.

All that is known of making colored fires will be made known to you (more or less).

Brain&Force - 25-9-2014 at 19:25

That is really weird. I have no issues with methanol and CuCl₂ and lighting the solution. Beautiful sea green flame.

Are you sure what you have is CuCl₂? Dissolve some in water, and do the following:

Add aluminium foil. Only copper and chloride together can dissolve aluminium foil.
Spray the mixture into an open flame.

Bert - 25-9-2014 at 20:05

In my experience, Potassium nitrate is useless for a good blue colored pyrotechnic flame.

I have not bothered to make blue fire mixes with Copper compounds and methanol, as the flame of pure alcohol is ALLREADY BLUE! Some who make such mixtures (for outdoors use only!) have added some methylene chloride to the alcohol to serve as a chlorine donor. THIS CAN GENERATE PHOSGENE GAS, do not try it indoors!!!

Black Copper oxide with any of several sugars (lactose was always popular, sucrose will work...) and Potassium chlorate are a classic recipe for BLUE fire. Cuprous chloride (CuCl) was a traditional favorite for blue stars, as was Copper oxy chloride and copper aceto arsenite (Paris green). CuCl2, not so much.

Potassium perchlorate, Copper carbonate, an organic fuel such as red gum and a SMALL amount of Magnesium will make you a bright blue flame, one that is best viewed from a good distance away. You may use a small percentage of Sulfur instead of the Magnesium when using PERCHLORATE, but DO NOT try a sulfur fueled CHLORATE mixture.

Ammonium perchlorate and Copper benzoate with a small ammount of lactose as a binder make a very nice blue, about as simple a mixture as you will find for this effect.

xfusion44 - 25-9-2014 at 22:12

@careysub

Thanks for that, I'm sure, I will search for this book

@Brain&Force

Yes, I'm sure, that I have CuCl2

I've tried this (reaction with aluminium foil and CuCl2) as soon as I made my first CuCl2 and it did react to give produce copper out of copper chloride

I didn't tried yet with methanol, because I don't have it and I'm little scared, because I don't know how it effects on you if it accidentaly comes in contact with skin (I've read that it can blind you), but it didn't worked with ethanol, when I tried it, maybe I had too low concentration, I'll give it another try

@Bert

I didn't say, that I'm using KNO3 for flame coloring

It's there just for giving off oxygen, so that sugar can burn

I really don't know, what results I would get if I'd use methanol instead of ethanol, but unfortunately I don't have methanol at hand currently.

And thanks for all that informational stuff

I decided to try again with ethanol, before posting this and it worked, but I used rather highly concentrated mixture of ethanol and anhydrous copper chloride, maybe I should try with higher concentration of anhydrous CuCl2 in mixture with KNO3 and sugar? Because first time I used CuCl2 dihydrate, is this maybe the reason that it didn't work? After the mixture stopped burning I could see some anhydrous CuCl2, so it must've dried it when it was on fire, but it didn't colored the flame.

PS: here are some pictures (not best quality, but enough that you can see). (just for comparison between burning CuCl2 in the air and in ethanol).

[Edited on 26-9-2014 by xfusion44]

Bert - 26-9-2014 at 00:37

Methanol + flame colorants burn with better colors due to lower amount of carbon in flame envelope- Free carbon causes the flame to look yellow.

xfusion44 - 26-9-2014 at 02:16

Quote: Originally posted by Bert

Methanol + flame colorants burn with better colors due to lower amount of carbon in flame envelope- Free carbon causes the flame to look yellow.

Oh, so that's probably the reason, why it's giving better colors with methanol.

But, how about mixing KNO3 + sugar + CuCl2 (anhydrous), can I expect better results with anhydrous CuCl2, than with dihydrate?

Thanks!

nezza - 26-9-2014 at 03:28

The best green flame colorant I have found for pyrotechnics is Barium chlorate. It gives an intense green colour, but Barium residues are toxic. I suspect Copper(II) chloride is hygroscopic so will not work too well in dry compositions.

Bert - 26-9-2014 at 05:24

Quote:

But, how about mixing KNO3 + sugar + CuCl2 (anhydrous), can I expect better results with anhydrous CuCl2, than with dihydrate?

Try using CuCl (Copper (I) chloride, cuprous chloride) INSTEAD of CuCl2 (Copper (II) chloride, cupric chloride). Then try substituting Potassium chlorate for Potassium nitrate. Try using lactose instead of sucrose. Let us know how these compare...

If you just want a nice green methanol flame, use boric acid... This forms trimethyl borate, and gives a good effect for little cost. Be careful of the fumes, do this outdoors or with an adequate hood! Methanol based gas line drier (HEET) and cheap roach powder are easy sources for the chemicals.

ALLWAYS avoid the fumes from burning methanol, these contain some formaldehyde. The warnings of blindness caused by ingesting methanol are due to methanol metabolizing to formaldehyde in the body- Formaldehyde has an affinity for the optic nerves.

[Edited on 26-9-2014 by Bert]

xfusion44 - 26-9-2014 at 16:22

@nezza

Looks like Barium chlorate isn't so cheap on ebay

Is there any other site where I can buy it cheaper?

@Bert

But where to get CuCl? There will be probably no problem to get other stuff as you mentioned... I've read that CuCl2 decomposes to Cl2 and Cu and some CuCl + 0.5Cl, but I'm not sure if it's true?

Thanks

xfusion44 - 26-9-2014 at 20:21

Hm, looks like this guy had the same problems: https://www.youtube.com/watch?v=hqWFm0spsFo

Copper chloride just doesn't want to give green flame...