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woelen
Super Administrator
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Tetraamminecopper peroxodisulfate indeed is somewhat energetic, but it also is unstable. If you store it, then after a few days it has decomposed to
some basic copper salt, which has lost all its energetic properties. Not really interesting to make. A better thing is making tetraamminecopper
sulfate monohydrate. This can be made from a concentrated copper sulfate solution, to which an excess amount of concentrated ammonia is added, so that
a very dark blue (nearly black) solution is obtained. To this, you have to add some ethanol in order to reduce the solubility. After some time, you
get really nice dark blue crystals of tetraamminecopper sulfate monohydrate. In a closed vial, these can be kept indefinitely.
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zed
International Hazard
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I've precipitated the material with methanol, which is cheap and available in the U.S..
The Tetraaminecopper Sulfate, is beautiful and apparently non-energetic.
Not so, the Nitrate, which I have seen detonated, in YouTube videos.
Now, the original post, was a long time ago. That Ammonium Sulfate has probably passed on.
So, the question is: What to do, with Ammonium Sulfate, folks have now?
Ummmm. Well, possibly if you Microwave it under vacuum, you can vaporize and remove the Ammonia.
Eventually leaving you with Concentrated H2SO4, which isn't very volatile.
Now, I don't need to do that. I can buy concentrated H2SO4 at my neighborhood, Home improvement center, or Hardware store. Cheap too.
Some of you however, are in countries where H2SO4, is harder to acquire.
This technique also works for producing Phosphoric Acid from Ammonium Phosphate, or dehydrating Phosphoric Acid, until it approximates Poly Phosphoric
Acid.
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woelen
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I don't think that strongly heating ammonium sulfate produces H2SO4.
First, on heating, it loses ammonia. I have tried that myself and it definitely gives off ammonia. What remains behind becomes acidic. It could be
considered impure NH4HSO4 (ammonium bisulfate, mixed with ammonium sulfate).
I suspect that on stronger heating, there will be complete decomposition by internal oxidation/reduction. The ammonium ion then reduces all sulfate to
SO2 and H2O, itself being converted to N2. I think that on strong heating of ammonium sulfate you get a mix of NH3, H2O, N2 and maybe a little H2SO4
or NH4HSO4, which is reformed from the gas mix. No way to obtain pure clean H2SO4.
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clearly_not_atara
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It is my general understanding that heating ammonium sulfate leads first to the bisulfate, then to the pyrosulfate (250-300 C):
http://www.sciencemadness.org/talk/viewthread.php?tid=4689
Pyrosulfates decompose around ~400 C to SO3; NH4Br decomposes at 450 C, and HBr is similar to H2S2O7 in Hammett strength, so I expect the sulfate
anion to decompose before losing NH3. The result is most likely redox decomp. I imagine the products are quite noxious, so if you're trying to make
the pyrosulfate, heating should be careful.
I would also imagine that ammonium pyrosulfate is probably good for something, but I'm not sure what. Maybe sulfamate?
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