24 replies to this topic

[Mumbles]

Sounds like someone has some Paris Green in mind.

Glacial acetic acid may be available from a photographic supplier. Someone from your side of the ocean may be more assistance.

Arsenious acid may be hard to find, as it only exists in solution. More commonly Arsenic trioxide is dissolved in water to form it, or neutralized with NaOH to form the sodium arsenite called for in some proceedures. As2O3 is sometimes sold as rat poison, but I this is generally the hard one to find.

[MDH]

I have been meaning to begin a topic about paris green, mostly out of curiosity in regards to why it is supposed to produce such an amazing blue.

I have heard several theories, but none of them make any sense to me.

[AdmiralDonSnider]

I have been meaning to begin a topic about paris green, mostly out of curiosity in regards to why it is supposed to produce such an amazing blue.

I have heard several theories, but none of them make any sense to me.

I was told that it is the arsenic which makes it such a good color producing agent. This also is the reason why substitutes like copper acetate, CuO, CuCO3 etc. will not work very well. The arsenic mediates the chlorine transfer to the copper. Other elements as sulfur are also said to be capable of doing that; thus copper sulphide, which is almost as hard to obtain, is said to give a good substitute. If you take this theory into account, it also explains why the old formulas often contained arsenic compounds such as realgar or orpiment.

[MDH]

Then in theory, copper arsenate should also work, yet it has been dismissed as inferior to paris green.

Additionally, the variety of paris greens available supposedly produce different blues - the lighter green grade produces an inferior one to the darker grade. But again - they both contain arsenic. Why is one better than the other if the arsenic is the secret ingredient in both?

Edited by MDH, 09 March 2010 - 01:58 PM.

[a_bab]

It really saddens me that paris green seems to be more and more looked upon as the ultimate blue producer. As someone who saw it's blue, I must confess that no other composition can beat it to this date, no matter what ammonium perchlorate/exotic copper compound may use.
Still, just for the thrill of having the best blue (which may not even be the case, as seen: different grades of paris green, crappy oxydizers and such) we don't think about the future generations. One thing is for sure: I'd be willing to be far away from a show with blues that I know to made by arsenic. I'm saying all of these as someone who actually lived in a town that used to process stuff like lead, zinc and arsenic, and someone very aware of it's effects.

Nowadays there's a global tendency of getting rid of things like lead and mercury just because of the longtime enviromental issues they create. Because of this, mercury price had dropped to half. Still, to some this is not important 'cause they want to get the best blue.

[AdmiralDonSnider]

Then in theory, copper arsenate should also work, yet it has been dismissed as inferior to paris green.

Additionally, the variety of paris greens available supposedly produce different blues - the lighter green grade produces an inferior one to the darker grade. But again - they both contain arsenic. Why is one better than the other if the arsenic is the secret ingredient in both?

This requires someone more skillfull in chemistry to answer; maybe the different chemical structure of the two arsenic compounds, arsenite and arsenate, plays a major role. Maybe the acetate, in combination with the arsenic, is the key. Not sure in how far the differently colored paris greens are discernable chemically.

[MDH]

If you do manage to obtain paris green somehow, I would also like a sample of it. I have many exotic reagents I would like to test it against.

Some of them include sulfonates, diformates and a few chlorinated phenols from generic outdated garden herbicides.

Edited by MDH, 12 March 2010 - 03:35 AM.

[CCH Concepts]

The arsenic mediates the chlorine transfer to the copper. Other elements as sulfur are also said to be capable of doing that; thus copper sulphide, which is almost as hard to obtain, is said to give a good substitute.

is this because it’s a catalyst, I know copper sulphate is a know catalyst. this would explain what the chlorine reacts more readily with the copper.

[Potassium chlorate]

Paris Green is possible to buy in Sweden but only with a permit, which you most likely won't get as a private citizen.

Cupper sulfide seems pretty promising, though, but is also very hard to get hold of.

Arsenic and sulfur working as mediators for the chlorine is possibly the explanation to why they held on to chlorate/sulfur etc. as long as they actually did, because the dangers both in toxicity as well as of spontaneous reactions were well known already in the 18th Century.

[MDH]

It's true, at least in regards to sulfur it is, anyway. A mixture of copper oxide, potassium perchlorate and sulfur will burn blue, as where with an organic reagent it will burn green.

[Potassium chlorate]

What do you think about this?

KClO4 70%
CuCO3 15%
S 10%
Dextrin 5%

It's the approximate ratios I get from comparing many different blue compositions.

From what I've understood, you can in principle substitute copper oxide for carbonate and vice versa. Correct me if I'm wrong.

Or this one, using parlon both as a binder and a chlorine donor:

KClO4 60%
CuCO3 12%
Parlon 18%
Sulfur 10%

Edited by Pyroswede, 25 March 2010 - 11:20 AM.

[MDH]

I don't think that will work so well. For one reason or another - some say it is the oversaturation produced by the carbonate ion - copper oxide is known to produce better blues than carbonate.

Try mixing small, unmeasured amounts of composition with just copper oxide, sulfur and potassium perchlorate on the ground. It does produce blue instead of the normal green. But if you make a mixture of potassium perchlorate, copper oxide and dextrin, it will burn green.

For some reason, the sulfur is ensuring that Cl from the decomposing potassium perchlorate produce copper monochloride.

As I said, I have never seen realgar or other arsenic reagents written as having accelerated the production of blue. Only Paris green seems to do this.

The Chinese have a composition which they use in bombette cakes and fountains. I do not remember the source of this composition, but it has always stuck in my head because it is distinctively known for its massive amount of copper oxide (there should be a mention on recreational pyrotechnics somewhere):

Chinese blue #1
Potassium Perchlorate, 39
Copper Oxide, 37
Sulfur, 15
HCB, 7
Red Gum, 2

It uses sulfur as its primary fuel.

Edited by MDH, 06 April 2010 - 07:29 PM.

[Potassium chlorate]

OK. I can simply turn my carbonate into oxide by heating it in a stove.

What is HCB?